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 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  libata-eh.c - libata error handling
  *
  *  Copyright 2006 Tejun Heo <htejun@gmail.com>
  *
  *  libata documentation is available via 'make {ps|pdf}docs',
  *  as Documentation/driver-api/libata.rst
  *
  *  Hardware documentation available from http://www.t13.org/ and
  *  http://www.sata-io.org/
  */
 
 #include <linux/kernel.h>
 #include <linux/blkdev.h>
 #include <linux/export.h>
 #include <linux/pci.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
 #include "../scsi/scsi_transport_api.h"
 
 #include <linux/libata.h>
 
 #include <trace/events/libata.h>
 #include "libata.h"
 
 enum {
     /* speed down verdicts */
     ATA_EH_SPDN_NCQ_OFF     = (1 << 0),
     ATA_EH_SPDN_SPEED_DOWN      = (1 << 1),
     ATA_EH_SPDN_FALLBACK_TO_PIO = (1 << 2),
     ATA_EH_SPDN_KEEP_ERRORS     = (1 << 3),
 
     /* error flags */
     ATA_EFLAG_IS_IO         = (1 << 0),
     ATA_EFLAG_DUBIOUS_XFER      = (1 << 1),
     ATA_EFLAG_OLD_ER                = (1 << 31),
 
     /* error categories */
     ATA_ECAT_NONE           = 0,
     ATA_ECAT_ATA_BUS        = 1,
     ATA_ECAT_TOUT_HSM       = 2,
     ATA_ECAT_UNK_DEV        = 3,
     ATA_ECAT_DUBIOUS_NONE       = 4,
     ATA_ECAT_DUBIOUS_ATA_BUS    = 5,
     ATA_ECAT_DUBIOUS_TOUT_HSM   = 6,
     ATA_ECAT_DUBIOUS_UNK_DEV    = 7,
     ATA_ECAT_NR         = 8,
 
     ATA_EH_CMD_DFL_TIMEOUT      =  5000,
 
     /* always put at least this amount of time between resets */
     ATA_EH_RESET_COOL_DOWN      =  5000,
 
     /* Waiting in ->prereset can never be reliable.  It's
      * sometimes nice to wait there but it can't be depended upon;
      * otherwise, we wouldn't be resetting.  Just give it enough
      * time for most drives to spin up.
      */
     ATA_EH_PRERESET_TIMEOUT     = 10000,
     ATA_EH_FASTDRAIN_INTERVAL   =  3000,
 
     ATA_EH_UA_TRIES         = 5,
 
     /* probe speed down parameters, see ata_eh_schedule_probe() */
     ATA_EH_PROBE_TRIAL_INTERVAL = 60000,    /* 1 min */
     ATA_EH_PROBE_TRIALS     = 2,
 };
 
 /* The following table determines how we sequence resets.  Each entry
  * represents timeout for that try.  The first try can be soft or
  * hardreset.  All others are hardreset if available.  In most cases
  * the first reset w/ 10sec timeout should succeed.  Following entries
  * are mostly for error handling, hotplug and those outlier devices that
  * take an exceptionally long time to recover from reset.
  */
 static const unsigned long ata_eh_reset_timeouts[] = {
     10000,  /* most drives spin up by 10sec */
     10000,  /* > 99% working drives spin up before 20sec */
     35000,  /* give > 30 secs of idleness for outlier devices */
      5000,  /* and sweet one last chance */
     ULONG_MAX, /* > 1 min has elapsed, give up */
 };
 
 static const unsigned int ata_eh_identify_timeouts[] = {
      5000,  /* covers > 99% of successes and not too boring on failures */
     10000,  /* combined time till here is enough even for media access */
     30000,  /* for true idiots */
     UINT_MAX,
 };
 
 static const unsigned int ata_eh_revalidate_timeouts[] = {
     15000,  /* Some drives are slow to read log pages when waking-up */
     15000,  /* combined time till here is enough even for media access */
     UINT_MAX,
 };
 
 static const unsigned int ata_eh_flush_timeouts[] = {
     15000,  /* be generous with flush */
     15000,  /* ditto */
     30000,  /* and even more generous */
     UINT_MAX,
 };
 
 static const unsigned int ata_eh_other_timeouts[] = {
      5000,  /* same rationale as identify timeout */
     10000,  /* ditto */
     /* but no merciful 30sec for other commands, it just isn't worth it */
     UINT_MAX,
 };
 
 struct ata_eh_cmd_timeout_ent {
     const u8        *commands;
     const unsigned int  *timeouts;
 };
 
 /* The following table determines timeouts to use for EH internal
  * commands.  Each table entry is a command class and matches the
  * commands the entry applies to and the timeout table to use.
  *
  * On the retry after a command timed out, the next timeout value from
  * the table is used.  If the table doesn't contain further entries,
  * the last value is used.
  *
  * ehc->cmd_timeout_idx keeps track of which timeout to use per
  * command class, so if SET_FEATURES times out on the first try, the
  * next try will use the second timeout value only for that class.
  */
 #define CMDS(cmds...)   (const u8 []){ cmds, 0 }
 static const struct ata_eh_cmd_timeout_ent
 ata_eh_cmd_timeout_table[ATA_EH_CMD_TIMEOUT_TABLE_SIZE] = {
     { .commands = CMDS(ATA_CMD_ID_ATA, ATA_CMD_ID_ATAPI),
       .timeouts = ata_eh_identify_timeouts, },
     { .commands = CMDS(ATA_CMD_READ_LOG_EXT, ATA_CMD_READ_LOG_DMA_EXT),
       .timeouts = ata_eh_revalidate_timeouts, },
     { .commands = CMDS(ATA_CMD_READ_NATIVE_MAX, ATA_CMD_READ_NATIVE_MAX_EXT),
       .timeouts = ata_eh_other_timeouts, },
     { .commands = CMDS(ATA_CMD_SET_MAX, ATA_CMD_SET_MAX_EXT),
       .timeouts = ata_eh_other_timeouts, },
     { .commands = CMDS(ATA_CMD_SET_FEATURES),
       .timeouts = ata_eh_other_timeouts, },
     { .commands = CMDS(ATA_CMD_INIT_DEV_PARAMS),
       .timeouts = ata_eh_other_timeouts, },
     { .commands = CMDS(ATA_CMD_FLUSH, ATA_CMD_FLUSH_EXT),
       .timeouts = ata_eh_flush_timeouts },
 };
 #undef CMDS
 
 static void __ata_port_freeze(struct ata_port *ap);
 #ifdef CONFIG_PM
 static void ata_eh_handle_port_suspend(struct ata_port *ap);
 static void ata_eh_handle_port_resume(struct ata_port *ap);
 #else /* CONFIG_PM */
 static void ata_eh_handle_port_suspend(struct ata_port *ap)
 { }
 
 static void ata_eh_handle_port_resume(struct ata_port *ap)
 { }
 #endif /* CONFIG_PM */
 
 static __printf(2, 0) void __ata_ehi_pushv_desc(struct ata_eh_info *ehi,
                  const char *fmt, va_list args)
 {
     ehi->desc_len += vscnprintf(ehi->desc + ehi->desc_len,
                      ATA_EH_DESC_LEN - ehi->desc_len,
                      fmt, args);
 }
 
 /**
  *  __ata_ehi_push_desc - push error description without adding separator
  *  @ehi: target EHI
  *  @fmt: printf format string
  *
  *  Format string according to @fmt and append it to @ehi->desc.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 void __ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
 {
     va_list args;
 
     va_start(args, fmt);
     __ata_ehi_pushv_desc(ehi, fmt, args);
     va_end(args);
 }
 EXPORT_SYMBOL_GPL(__ata_ehi_push_desc);
 
 /**
  *  ata_ehi_push_desc - push error description with separator
  *  @ehi: target EHI
  *  @fmt: printf format string
  *
  *  Format string according to @fmt and append it to @ehi->desc.
  *  If @ehi->desc is not empty, ", " is added in-between.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 void ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
 {
     va_list args;
 
     if (ehi->desc_len)
         __ata_ehi_push_desc(ehi, ", ");
 
     va_start(args, fmt);
     __ata_ehi_pushv_desc(ehi, fmt, args);
     va_end(args);
 }
 EXPORT_SYMBOL_GPL(ata_ehi_push_desc);
 
 /**
  *  ata_ehi_clear_desc - clean error description
  *  @ehi: target EHI
  *
  *  Clear @ehi->desc.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 void ata_ehi_clear_desc(struct ata_eh_info *ehi)
 {
     ehi->desc[0] = '\0';
     ehi->desc_len = 0;
 }
 EXPORT_SYMBOL_GPL(ata_ehi_clear_desc);
 
 /**
  *  ata_port_desc - append port description
  *  @ap: target ATA port
  *  @fmt: printf format string
  *
  *  Format string according to @fmt and append it to port
  *  description.  If port description is not empty, " " is added
  *  in-between.  This function is to be used while initializing
  *  ata_host.  The description is printed on host registration.
  *
  *  LOCKING:
  *  None.
  */
 void ata_port_desc(struct ata_port *ap, const char *fmt, ...)
 {
     va_list args;
 
     WARN_ON(!(ap->pflags & ATA_PFLAG_INITIALIZING));
 
     if (ap->link.eh_info.desc_len)
         __ata_ehi_push_desc(&ap->link.eh_info, " ");
 
     va_start(args, fmt);
     __ata_ehi_pushv_desc(&ap->link.eh_info, fmt, args);
     va_end(args);
 }
 EXPORT_SYMBOL_GPL(ata_port_desc);
 
 #ifdef CONFIG_PCI
 /**
  *  ata_port_pbar_desc - append PCI BAR description
  *  @ap: target ATA port
  *  @bar: target PCI BAR
  *  @offset: offset into PCI BAR
  *  @name: name of the area
  *
  *  If @offset is negative, this function formats a string which
  *  contains the name, address, size and type of the BAR and
  *  appends it to the port description.  If @offset is zero or
  *  positive, only name and offsetted address is appended.
  *
  *  LOCKING:
  *  None.
  */
 void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset,
             const char *name)
 {
     struct pci_dev *pdev = to_pci_dev(ap->host->dev);
     char *type = "";
     unsigned long long start, len;
 
     if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
         type = "m";
     else if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
         type = "i";
 
     start = (unsigned long long)pci_resource_start(pdev, bar);
     len = (unsigned long long)pci_resource_len(pdev, bar);
 
     if (offset < 0)
         ata_port_desc(ap, "%s %s%llu@0x%llx", name, type, len, start);
     else
         ata_port_desc(ap, "%s 0x%llx", name,
                 start + (unsigned long long)offset);
 }
 EXPORT_SYMBOL_GPL(ata_port_pbar_desc);
 #endif /* CONFIG_PCI */
 
 static int ata_lookup_timeout_table(u8 cmd)
 {
     int i;
 
     for (i = 0; i < ATA_EH_CMD_TIMEOUT_TABLE_SIZE; i++) {
         const u8 *cur;
 
         for (cur = ata_eh_cmd_timeout_table[i].commands; *cur; cur++)
             if (*cur == cmd)
                 return i;
     }
 
     return -1;
 }
 
 /**
  *  ata_internal_cmd_timeout - determine timeout for an internal command
  *  @dev: target device
  *  @cmd: internal command to be issued
  *
  *  Determine timeout for internal command @cmd for @dev.
  *
  *  LOCKING:
  *  EH context.
  *
  *  RETURNS:
  *  Determined timeout.
  */
 unsigned int ata_internal_cmd_timeout(struct ata_device *dev, u8 cmd)
 {
     struct ata_eh_context *ehc = &dev->link->eh_context;
     int ent = ata_lookup_timeout_table(cmd);
     int idx;
 
     if (ent < 0)
         return ATA_EH_CMD_DFL_TIMEOUT;
 
     idx = ehc->cmd_timeout_idx[dev->devno][ent];
     return ata_eh_cmd_timeout_table[ent].timeouts[idx];
 }
 
 /**
  *  ata_internal_cmd_timed_out - notification for internal command timeout
  *  @dev: target device
  *  @cmd: internal command which timed out
  *
  *  Notify EH that internal command @cmd for @dev timed out.  This
  *  function should be called only for commands whose timeouts are
  *  determined using ata_internal_cmd_timeout().
  *
  *  LOCKING:
  *  EH context.
  */
 void ata_internal_cmd_timed_out(struct ata_device *dev, u8 cmd)
 {
     struct ata_eh_context *ehc = &dev->link->eh_context;
     int ent = ata_lookup_timeout_table(cmd);
     int idx;
 
     if (ent < 0)
         return;
 
     idx = ehc->cmd_timeout_idx[dev->devno][ent];
     if (ata_eh_cmd_timeout_table[ent].timeouts[idx + 1] != UINT_MAX)
         ehc->cmd_timeout_idx[dev->devno][ent]++;
 }
 
 static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
                  unsigned int err_mask)
 {
     struct ata_ering_entry *ent;
 
     WARN_ON(!err_mask);
 
     ering->cursor++;
     ering->cursor %= ATA_ERING_SIZE;
 
     ent = &ering->ring[ering->cursor];
     ent->eflags = eflags;
     ent->err_mask = err_mask;
     ent->timestamp = get_jiffies_64();
 }
 
 static struct ata_ering_entry *ata_ering_top(struct ata_ering *ering)
 {
     struct ata_ering_entry *ent = &ering->ring[ering->cursor];
 
     if (ent->err_mask)
         return ent;
     return NULL;
 }
 
 int ata_ering_map(struct ata_ering *ering,
           int (*map_fn)(struct ata_ering_entry *, void *),
           void *arg)
 {
     int idx, rc = 0;
     struct ata_ering_entry *ent;
 
     idx = ering->cursor;
     do {
         ent = &ering->ring[idx];
         if (!ent->err_mask)
             break;
         rc = map_fn(ent, arg);
         if (rc)
             break;
         idx = (idx - 1 + ATA_ERING_SIZE) % ATA_ERING_SIZE;
     } while (idx != ering->cursor);
 
     return rc;
 }
 
 static int ata_ering_clear_cb(struct ata_ering_entry *ent, void *void_arg)
 {
     ent->eflags |= ATA_EFLAG_OLD_ER;
     return 0;
 }
 
 static void ata_ering_clear(struct ata_ering *ering)
 {
     ata_ering_map(ering, ata_ering_clear_cb, NULL);
 }
 
 static unsigned int ata_eh_dev_action(struct ata_device *dev)
 {
     struct ata_eh_context *ehc = &dev->link->eh_context;
 
     return ehc->i.action | ehc->i.dev_action[dev->devno];
 }
 
 static void ata_eh_clear_action(struct ata_link *link, struct ata_device *dev,
                 struct ata_eh_info *ehi, unsigned int action)
 {
     struct ata_device *tdev;
 
     if (!dev) {
         ehi->action &= ~action;
         ata_for_each_dev(tdev, link, ALL)
             ehi->dev_action[tdev->devno] &= ~action;
     } else {
         /* doesn't make sense for port-wide EH actions */
         WARN_ON(!(action & ATA_EH_PERDEV_MASK));
 
         /* break ehi->action into ehi->dev_action */
         if (ehi->action & action) {
             ata_for_each_dev(tdev, link, ALL)
                 ehi->dev_action[tdev->devno] |=
                     ehi->action & action;
             ehi->action &= ~action;
         }
 
         /* turn off the specified per-dev action */
         ehi->dev_action[dev->devno] &= ~action;
     }
 }
 
 /**
  *  ata_eh_acquire - acquire EH ownership
  *  @ap: ATA port to acquire EH ownership for
  *
  *  Acquire EH ownership for @ap.  This is the basic exclusion
  *  mechanism for ports sharing a host.  Only one port hanging off
  *  the same host can claim the ownership of EH.
  *
  *  LOCKING:
  *  EH context.
  */
 void ata_eh_acquire(struct ata_port *ap)
 {
     mutex_lock(&ap->host->eh_mutex);
     WARN_ON_ONCE(ap->host->eh_owner);
     ap->host->eh_owner = current;
 }
 
 /**
  *  ata_eh_release - release EH ownership
  *  @ap: ATA port to release EH ownership for
  *
  *  Release EH ownership for @ap if the caller.  The caller must
  *  have acquired EH ownership using ata_eh_acquire() previously.
  *
  *  LOCKING:
  *  EH context.
  */
 void ata_eh_release(struct ata_port *ap)
 {
     WARN_ON_ONCE(ap->host->eh_owner != current);
     ap->host->eh_owner = NULL;
     mutex_unlock(&ap->host->eh_mutex);
 }
 
 static void ata_eh_unload(struct ata_port *ap)
 {
     struct ata_link *link;
     struct ata_device *dev;
     unsigned long flags;
 
     /* Restore SControl IPM and SPD for the next driver and
      * disable attached devices.
      */
     ata_for_each_link(link, ap, PMP_FIRST) {
         sata_scr_write(link, SCR_CONTROL, link->saved_scontrol & 0xff0);
         ata_for_each_dev(dev, link, ALL)
             ata_dev_disable(dev);
     }
 
     /* freeze and set UNLOADED */
     spin_lock_irqsave(ap->lock, flags);
 
     ata_port_freeze(ap);            /* won't be thawed */
     ap->pflags &= ~ATA_PFLAG_EH_PENDING;    /* clear pending from freeze */
     ap->pflags |= ATA_PFLAG_UNLOADED;
 
     spin_unlock_irqrestore(ap->lock, flags);
 }
 
 /**
  *  ata_scsi_error - SCSI layer error handler callback
  *  @host: SCSI host on which error occurred
  *
  *  Handles SCSI-layer-thrown error events.
  *
  *  LOCKING:
  *  Inherited from SCSI layer (none, can sleep)
  *
  *  RETURNS:
  *  Zero.
  */
 void ata_scsi_error(struct Scsi_Host *host)
 {
     struct ata_port *ap = ata_shost_to_port(host);
     unsigned long flags;
     LIST_HEAD(eh_work_q);
 
     spin_lock_irqsave(host->host_lock, flags);
     list_splice_init(&host->eh_cmd_q, &eh_work_q);
     spin_unlock_irqrestore(host->host_lock, flags);
 
     ata_scsi_cmd_error_handler(host, ap, &eh_work_q);
 
     /* If we timed raced normal completion and there is nothing to
        recover nr_timedout == 0 why exactly are we doing error recovery ? */
     ata_scsi_port_error_handler(host, ap);
 
     /* finish or retry handled scmd's and clean up */
     WARN_ON(!list_empty(&eh_work_q));
 
 }
 
 /**
  * ata_scsi_cmd_error_handler - error callback for a list of commands
  * @host:   scsi host containing the port
  * @ap:     ATA port within the host
  * @eh_work_q:  list of commands to process
  *
  * process the given list of commands and return those finished to the
  * ap->eh_done_q.  This function is the first part of the libata error
  * handler which processes a given list of failed commands.
  */
 void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
                 struct list_head *eh_work_q)
 {
     int i;
     unsigned long flags;
 
     /* make sure sff pio task is not running */
     ata_sff_flush_pio_task(ap);
 
     /* synchronize with host lock and sort out timeouts */
 
     /* For new EH, all qcs are finished in one of three ways -
      * normal completion, error completion, and SCSI timeout.
      * Both completions can race against SCSI timeout.  When normal
      * completion wins, the qc never reaches EH.  When error
      * completion wins, the qc has ATA_QCFLAG_FAILED set.
      *
      * When SCSI timeout wins, things are a bit more complex.
      * Normal or error completion can occur after the timeout but
      * before this point.  In such cases, both types of
      * completions are honored.  A scmd is determined to have
      * timed out iff its associated qc is active and not failed.
      */
     spin_lock_irqsave(ap->lock, flags);
     if (ap->ops->error_handler) {
         struct scsi_cmnd *scmd, *tmp;
         int nr_timedout = 0;
 
         /* This must occur under the ap->lock as we don't want
            a polled recovery to race the real interrupt handler
 
            The lost_interrupt handler checks for any completed but
            non-notified command and completes much like an IRQ handler.
 
            We then fall into the error recovery code which will treat
            this as if normal completion won the race */
 
         if (ap->ops->lost_interrupt)
             ap->ops->lost_interrupt(ap);
 
         list_for_each_entry_safe(scmd, tmp, eh_work_q, eh_entry) {
             struct ata_queued_cmd *qc;
 
             ata_qc_for_each_raw(ap, qc, i) {
                 if (qc->flags & ATA_QCFLAG_ACTIVE &&
                     qc->scsicmd == scmd)
                     break;
             }
 
             if (i < ATA_MAX_QUEUE) {
                 /* the scmd has an associated qc */
                 if (!(qc->flags & ATA_QCFLAG_FAILED)) {
                     /* which hasn't failed yet, timeout */
                     qc->err_mask |= AC_ERR_TIMEOUT;
                     qc->flags |= ATA_QCFLAG_FAILED;
                     nr_timedout++;
                 }
             } else {
                 /* Normal completion occurred after
                  * SCSI timeout but before this point.
                  * Successfully complete it.
                  */
                 scmd->retries = scmd->allowed;
                 scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
             }
         }
 
         /* If we have timed out qcs.  They belong to EH from
          * this point but the state of the controller is
          * unknown.  Freeze the port to make sure the IRQ
          * handler doesn't diddle with those qcs.  This must
          * be done atomically w.r.t. setting QCFLAG_FAILED.
          */
         if (nr_timedout)
             __ata_port_freeze(ap);
 
 
         /* initialize eh_tries */
         ap->eh_tries = ATA_EH_MAX_TRIES;
     }
     spin_unlock_irqrestore(ap->lock, flags);
 
 }
 EXPORT_SYMBOL(ata_scsi_cmd_error_handler);
 
 /**
  * ata_scsi_port_error_handler - recover the port after the commands
  * @host:   SCSI host containing the port
  * @ap:     the ATA port
  *
  * Handle the recovery of the port @ap after all the commands
  * have been recovered.
  */
 void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap)
 {
     unsigned long flags;
 
     /* invoke error handler */
     if (ap->ops->error_handler) {
         struct ata_link *link;
 
         /* acquire EH ownership */
         ata_eh_acquire(ap);
  repeat:
         /* kill fast drain timer */
         del_timer_sync(&ap->fastdrain_timer);
 
         /* process port resume request */
         ata_eh_handle_port_resume(ap);
 
         /* fetch & clear EH info */
         spin_lock_irqsave(ap->lock, flags);
 
         ata_for_each_link(link, ap, HOST_FIRST) {
             struct ata_eh_context *ehc = &link->eh_context;
             struct ata_device *dev;
 
             memset(&link->eh_context, 0, sizeof(link->eh_context));
             link->eh_context.i = link->eh_info;
             memset(&link->eh_info, 0, sizeof(link->eh_info));
 
             ata_for_each_dev(dev, link, ENABLED) {
                 int devno = dev->devno;
 
                 ehc->saved_xfer_mode[devno] = dev->xfer_mode;
                 if (ata_ncq_enabled(dev))
                     ehc->saved_ncq_enabled |= 1 << devno;
             }
         }
 
         ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
         ap->pflags &= ~ATA_PFLAG_EH_PENDING;
         ap->excl_link = NULL;   /* don't maintain exclusion over EH */
 
         spin_unlock_irqrestore(ap->lock, flags);
 
         /* invoke EH, skip if unloading or suspended */
         if (!(ap->pflags & (ATA_PFLAG_UNLOADING | ATA_PFLAG_SUSPENDED)))
             ap->ops->error_handler(ap);
         else {
             /* if unloading, commence suicide */
             if ((ap->pflags & ATA_PFLAG_UNLOADING) &&
                 !(ap->pflags & ATA_PFLAG_UNLOADED))
                 ata_eh_unload(ap);
             ata_eh_finish(ap);
         }
 
         /* process port suspend request */
         ata_eh_handle_port_suspend(ap);
 
         /* Exception might have happened after ->error_handler
          * recovered the port but before this point.  Repeat
          * EH in such case.
          */
         spin_lock_irqsave(ap->lock, flags);
 
         if (ap->pflags & ATA_PFLAG_EH_PENDING) {
             if (--ap->eh_tries) {
                 spin_unlock_irqrestore(ap->lock, flags);
                 goto repeat;
             }
             ata_port_err(ap,
                      "EH pending after %d tries, giving up\n",
                      ATA_EH_MAX_TRIES);
             ap->pflags &= ~ATA_PFLAG_EH_PENDING;
         }
 
         /* this run is complete, make sure EH info is clear */
         ata_for_each_link(link, ap, HOST_FIRST)
             memset(&link->eh_info, 0, sizeof(link->eh_info));
 
         /* end eh (clear host_eh_scheduled) while holding
          * ap->lock such that if exception occurs after this
          * point but before EH completion, SCSI midlayer will
          * re-initiate EH.
          */
         ap->ops->end_eh(ap);
 
         spin_unlock_irqrestore(ap->lock, flags);
         ata_eh_release(ap);
     } else {
         WARN_ON(ata_qc_from_tag(ap, ap->link.active_tag) == NULL);
         ap->ops->eng_timeout(ap);
     }
 
     scsi_eh_flush_done_q(&ap->eh_done_q);
 
     /* clean up */
     spin_lock_irqsave(ap->lock, flags);
 
     if (ap->pflags & ATA_PFLAG_LOADING)
         ap->pflags &= ~ATA_PFLAG_LOADING;
     else if ((ap->pflags & ATA_PFLAG_SCSI_HOTPLUG) &&
         !(ap->flags & ATA_FLAG_SAS_HOST))
         schedule_delayed_work(&ap->hotplug_task, 0);
 
     if (ap->pflags & ATA_PFLAG_RECOVERED)
         ata_port_info(ap, "EH complete\n");
 
     ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);
 
     /* tell wait_eh that we're done */
     ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
     wake_up_all(&ap->eh_wait_q);
 
     spin_unlock_irqrestore(ap->lock, flags);
 }
 EXPORT_SYMBOL_GPL(ata_scsi_port_error_handler);
 
 /**
  *  ata_port_wait_eh - Wait for the currently pending EH to complete
  *  @ap: Port to wait EH for
  *
  *  Wait until the currently pending EH is complete.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 void ata_port_wait_eh(struct ata_port *ap)
 {
     unsigned long flags;
     DEFINE_WAIT(wait);
 
  retry:
     spin_lock_irqsave(ap->lock, flags);
 
     while (ap->pflags & (ATA_PFLAG_EH_PENDING | ATA_PFLAG_EH_IN_PROGRESS)) {
         prepare_to_wait(&ap->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
         spin_unlock_irqrestore(ap->lock, flags);
         schedule();
         spin_lock_irqsave(ap->lock, flags);
     }
     finish_wait(&ap->eh_wait_q, &wait);
 
     spin_unlock_irqrestore(ap->lock, flags);
 
     /* make sure SCSI EH is complete */
     if (scsi_host_in_recovery(ap->scsi_host)) {
         ata_msleep(ap, 10);
         goto retry;
     }
 }
 EXPORT_SYMBOL_GPL(ata_port_wait_eh);
 
 static unsigned int ata_eh_nr_in_flight(struct ata_port *ap)
 {
     struct ata_queued_cmd *qc;
     unsigned int tag;
     unsigned int nr = 0;
 
     /* count only non-internal commands */
     ata_qc_for_each(ap, qc, tag) {
         if (qc)
             nr++;
     }
 
     return nr;
 }
 
 void ata_eh_fastdrain_timerfn(struct timer_list *t)
 {
     struct ata_port *ap = from_timer(ap, t, fastdrain_timer);
     unsigned long flags;
     unsigned int cnt;
 
     spin_lock_irqsave(ap->lock, flags);
 
     cnt = ata_eh_nr_in_flight(ap);
 
     /* are we done? */
     if (!cnt)
         goto out_unlock;
 
     if (cnt == ap->fastdrain_cnt) {
         struct ata_queued_cmd *qc;
         unsigned int tag;
 
         /* No progress during the last interval, tag all
          * in-flight qcs as timed out and freeze the port.
          */
         ata_qc_for_each(ap, qc, tag) {
             if (qc)
                 qc->err_mask |= AC_ERR_TIMEOUT;
         }
 
         ata_port_freeze(ap);
     } else {
         /* some qcs have finished, give it another chance */
         ap->fastdrain_cnt = cnt;
         ap->fastdrain_timer.expires =
             ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
         add_timer(&ap->fastdrain_timer);
     }
 
  out_unlock:
     spin_unlock_irqrestore(ap->lock, flags);
 }
 
 /**
  *  ata_eh_set_pending - set ATA_PFLAG_EH_PENDING and activate fast drain
  *  @ap: target ATA port
  *  @fastdrain: activate fast drain
  *
  *  Set ATA_PFLAG_EH_PENDING and activate fast drain if @fastdrain
  *  is non-zero and EH wasn't pending before.  Fast drain ensures
  *  that EH kicks in in timely manner.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
 {
     unsigned int cnt;
 
     /* already scheduled? */
     if (ap->pflags & ATA_PFLAG_EH_PENDING)
         return;
 
     ap->pflags |= ATA_PFLAG_EH_PENDING;
 
     if (!fastdrain)
         return;
 
     /* do we have in-flight qcs? */
     cnt = ata_eh_nr_in_flight(ap);
     if (!cnt)
         return;
 
     /* activate fast drain */
     ap->fastdrain_cnt = cnt;
     ap->fastdrain_timer.expires =
         ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
     add_timer(&ap->fastdrain_timer);
 }
 
 /**
  *  ata_qc_schedule_eh - schedule qc for error handling
  *  @qc: command to schedule error handling for
  *
  *  Schedule error handling for @qc.  EH will kick in as soon as
  *  other commands are drained.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
 {
     struct ata_port *ap = qc->ap;
 
     WARN_ON(!ap->ops->error_handler);
 
     qc->flags |= ATA_QCFLAG_FAILED;
     ata_eh_set_pending(ap, 1);
 
     /* The following will fail if timeout has already expired.
      * ata_scsi_error() takes care of such scmds on EH entry.
      * Note that ATA_QCFLAG_FAILED is unconditionally set after
      * this function completes.
      */
     blk_abort_request(scsi_cmd_to_rq(qc->scsicmd));
 }
 
 /**
  * ata_std_sched_eh - non-libsas ata_ports issue eh with this common routine
  * @ap: ATA port to schedule EH for
  *
  *  LOCKING: inherited from ata_port_schedule_eh
  *  spin_lock_irqsave(host lock)
  */
 void ata_std_sched_eh(struct ata_port *ap)
 {
     WARN_ON(!ap->ops->error_handler);
 
     if (ap->pflags & ATA_PFLAG_INITIALIZING)
         return;
 
     ata_eh_set_pending(ap, 1);
     scsi_schedule_eh(ap->scsi_host);
 
     trace_ata_std_sched_eh(ap);
 }
 EXPORT_SYMBOL_GPL(ata_std_sched_eh);
 
 /**
  * ata_std_end_eh - non-libsas ata_ports complete eh with this common routine
  * @ap: ATA port to end EH for
  *
  * In the libata object model there is a 1:1 mapping of ata_port to
  * shost, so host fields can be directly manipulated under ap->lock, in
  * the libsas case we need to hold a lock at the ha->level to coordinate
  * these events.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 void ata_std_end_eh(struct ata_port *ap)
 {
     struct Scsi_Host *host = ap->scsi_host;
 
     host->host_eh_scheduled = 0;
 }
 EXPORT_SYMBOL(ata_std_end_eh);
 
 
 /**
  *  ata_port_schedule_eh - schedule error handling without a qc
  *  @ap: ATA port to schedule EH for
  *
  *  Schedule error handling for @ap.  EH will kick in as soon as
  *  all commands are drained.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 void ata_port_schedule_eh(struct ata_port *ap)
 {
     /* see: ata_std_sched_eh, unless you know better */
     ap->ops->sched_eh(ap);
 }
 EXPORT_SYMBOL_GPL(ata_port_schedule_eh);
 
 static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)
 {
     struct ata_queued_cmd *qc;
     int tag, nr_aborted = 0;
 
     WARN_ON(!ap->ops->error_handler);
 
     /* we're gonna abort all commands, no need for fast drain */
     ata_eh_set_pending(ap, 0);
 
     /* include internal tag in iteration */
     ata_qc_for_each_with_internal(ap, qc, tag) {
         if (qc && (!link || qc->dev->link == link)) {
             qc->flags |= ATA_QCFLAG_FAILED;
             ata_qc_complete(qc);
             nr_aborted++;
         }
     }
 
     if (!nr_aborted)
         ata_port_schedule_eh(ap);
 
     return nr_aborted;
 }
 
 /**
  *  ata_link_abort - abort all qc's on the link
  *  @link: ATA link to abort qc's for
  *
  *  Abort all active qc's active on @link and schedule EH.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  *
  *  RETURNS:
  *  Number of aborted qc's.
  */
 int ata_link_abort(struct ata_link *link)
 {
     return ata_do_link_abort(link->ap, link);
 }
 EXPORT_SYMBOL_GPL(ata_link_abort);
 
 /**
  *  ata_port_abort - abort all qc's on the port
  *  @ap: ATA port to abort qc's for
  *
  *  Abort all active qc's of @ap and schedule EH.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host_set lock)
  *
  *  RETURNS:
  *  Number of aborted qc's.
  */
 int ata_port_abort(struct ata_port *ap)
 {
     return ata_do_link_abort(ap, NULL);
 }
 EXPORT_SYMBOL_GPL(ata_port_abort);
 
 /**
  *  __ata_port_freeze - freeze port
  *  @ap: ATA port to freeze
  *
  *  This function is called when HSM violation or some other
  *  condition disrupts normal operation of the port.  Frozen port
  *  is not allowed to perform any operation until the port is
  *  thawed, which usually follows a successful reset.
  *
  *  ap->ops->freeze() callback can be used for freezing the port
  *  hardware-wise (e.g. mask interrupt and stop DMA engine).  If a
  *  port cannot be frozen hardware-wise, the interrupt handler
  *  must ack and clear interrupts unconditionally while the port
  *  is frozen.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  */
 static void __ata_port_freeze(struct ata_port *ap)
 {
     WARN_ON(!ap->ops->error_handler);
 
     if (ap->ops->freeze)
         ap->ops->freeze(ap);
 
     ap->pflags |= ATA_PFLAG_FROZEN;
 
     trace_ata_port_freeze(ap);
 }
 
 /**
  *  ata_port_freeze - abort & freeze port
  *  @ap: ATA port to freeze
  *
  *  Abort and freeze @ap.  The freeze operation must be called
  *  first, because some hardware requires special operations
  *  before the taskfile registers are accessible.
  *
  *  LOCKING:
  *  spin_lock_irqsave(host lock)
  *
  *  RETURNS:
  *  Number of aborted commands.
  */
 int ata_port_freeze(struct ata_port *ap)
 {
     int nr_aborted;
 
     WARN_ON(!ap->ops->error_handler);
 
     __ata_port_freeze(ap);
     nr_aborted = ata_port_abort(ap);
 
     return nr_aborted;
 }
 EXPORT_SYMBOL_GPL(ata_port_freeze);
 
 /**
  *  ata_eh_freeze_port - EH helper to freeze port
  *  @ap: ATA port to freeze
  *
  *  Freeze @ap.
  *
  *  LOCKING:
  *  None.
  */
 void ata_eh_freeze_port(struct ata_port *ap)
 {
     unsigned long flags;
 
     if (!ap->ops->error_handler)
         return;
 
     spin_lock_irqsave(ap->lock, flags);
     __ata_port_freeze(ap);
     spin_unlock_irqrestore(ap->lock, flags);
 }
 EXPORT_SYMBOL_GPL(ata_eh_freeze_port);
 
 /**
  *  ata_eh_thaw_port - EH helper to thaw port
  *  @ap: ATA port to thaw
  *
  *  Thaw frozen port @ap.
  *
  *  LOCKING:
  *  None.
  */
 void ata_eh_thaw_port(struct ata_port *ap)
 {
     unsigned long flags;
 
     if (!ap->ops->error_handler)
         return;
 
     spin_lock_irqsave(ap->lock, flags);
 
     ap->pflags &= ~ATA_PFLAG_FROZEN;
 
     if (ap->ops->thaw)
         ap->ops->thaw(ap);
 
     spin_unlock_irqrestore(ap->lock, flags);
 
     trace_ata_port_thaw(ap);
 }
 
 static void ata_eh_scsidone(struct scsi_cmnd *scmd)
 {
     /* nada */
 }
 
 static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
 {
     struct ata_port *ap = qc->ap;
     struct scsi_cmnd *scmd = qc->scsicmd;
     unsigned long flags;
 
     spin_lock_irqsave(ap->lock, flags);
     qc->scsidone = ata_eh_scsidone;
     __ata_qc_complete(qc);
     WARN_ON(ata_tag_valid(qc->tag));
     spin_unlock_irqrestore(ap->lock, flags);
 
     scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
 }
 
 /**
  *  ata_eh_qc_complete - Complete an active ATA command from EH
  *  @qc: Command to complete
  *
  *  Indicate to the mid and upper layers that an ATA command has
  *  completed.  To be used from EH.
  */
 void ata_eh_qc_complete(struct ata_queued_cmd *qc)
 {
     struct scsi_cmnd *scmd = qc->scsicmd;
     scmd->retries = scmd->allowed;
     __ata_eh_qc_complete(qc);
 }
 
 /**
  *  ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
  *  @qc: Command to retry
  *
  *  Indicate to the mid and upper layers that an ATA command
  *  should be retried.  To be used from EH.
  *
  *  SCSI midlayer limits the number of retries to scmd->allowed.
  *  scmd->allowed is incremented for commands which get retried
  *  due to unrelated failures (qc->err_mask is zero).
  */
 void ata_eh_qc_retry(struct ata_queued_cmd *qc)
 {
     struct scsi_cmnd *scmd = qc->scsicmd;
     if (!qc->err_mask)
         scmd->allowed++;
     __ata_eh_qc_complete(qc);
 }
 
 /**
  *  ata_dev_disable - disable ATA device
  *  @dev: ATA device to disable
  *
  *  Disable @dev.
  *
  *  Locking:
  *  EH context.
  */
 void ata_dev_disable(struct ata_device *dev)
 {
     if (!ata_dev_enabled(dev))
         return;
 
     ata_dev_warn(dev, "disable device\n");
     ata_acpi_on_disable(dev);
     ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 | ATA_DNXFER_QUIET);
     dev->class++;
 
     /* From now till the next successful probe, ering is used to
      * track probe failures.  Clear accumulated device error info.
      */
     ata_ering_clear(&dev->ering);
 }
 EXPORT_SYMBOL_GPL(ata_dev_disable);
 
 /**
  *  ata_eh_detach_dev - detach ATA device
  *  @dev: ATA device to detach
  *
  *  Detach @dev.
  *
  *  LOCKING:
  *  None.
  */
 void ata_eh_detach_dev(struct ata_device *dev)
 {
     struct ata_link *link = dev->link;
     struct ata_port *ap = link->ap;
     struct ata_eh_context *ehc = &link->eh_context;
     unsigned long flags;
 
     ata_dev_disable(dev);
 
     spin_lock_irqsave(ap->lock, flags);
 
     dev->flags &= ~ATA_DFLAG_DETACH;
 
     if (ata_scsi_offline_dev(dev)) {
         dev->flags |= ATA_DFLAG_DETACHED;
         ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
     }
 
     /* clear per-dev EH info */
     ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
     ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
     ehc->saved_xfer_mode[dev->devno] = 0;
     ehc->saved_ncq_enabled &= ~(1 << dev->devno);
 
     spin_unlock_irqrestore(ap->lock, flags);
 }
 
 /**
  *  ata_eh_about_to_do - about to perform eh_action
  *  @link: target ATA link
  *  @dev: target ATA dev for per-dev action (can be NULL)
  *  @action: action about to be performed
  *
  *  Called just before performing EH actions to clear related bits
  *  in @link->eh_info such that eh actions are not unnecessarily
  *  repeated.
  *
  *  LOCKING:
  *  None.
  */
 void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
             unsigned int action)
 {
     struct ata_port *ap = link->ap;
     struct ata_eh_info *ehi = &link->eh_info;
     struct ata_eh_context *ehc = &link->eh_context;
     unsigned long flags;
 
     trace_ata_eh_about_to_do(link, dev ? dev->devno : 0, action);
 
     spin_lock_irqsave(ap->lock, flags);
 
     ata_eh_clear_action(link, dev, ehi, action);
 
     /* About to take EH action, set RECOVERED.  Ignore actions on
      * slave links as master will do them again.
      */
     if (!(ehc->i.flags & ATA_EHI_QUIET) && link != ap->slave_link)
         ap->pflags |= ATA_PFLAG_RECOVERED;
 
     spin_unlock_irqrestore(ap->lock, flags);
 }
 
 /**
  *  ata_eh_done - EH action complete
  *  @link: ATA link for which EH actions are complete
  *  @dev: target ATA dev for per-dev action (can be NULL)
  *  @action: action just completed
  *
  *  Called right after performing EH actions to clear related bits
  *  in @link->eh_context.
  *
  *  LOCKING:
  *  None.
  */
 void ata_eh_done(struct ata_link *link, struct ata_device *dev,
          unsigned int action)
 {
     struct ata_eh_context *ehc = &link->eh_context;
 
     trace_ata_eh_done(link, dev ? dev->devno : 0, action);
 
     ata_eh_clear_action(link, dev, &ehc->i, action);
 }
 
 /**
  *  ata_err_string - convert err_mask to descriptive string
  *  @err_mask: error mask to convert to string
  *
  *  Convert @err_mask to descriptive string.  Errors are
  *  prioritized according to severity and only the most severe
  *  error is reported.
  *
  *  LOCKING:
  *  None.
  *
  *  RETURNS:
  *  Descriptive string for @err_mask
  */
 static const char *ata_err_string(unsigned int err_mask)
 {
     if (err_mask & AC_ERR_HOST_BUS)
         return "host bus error";
     if (err_mask & AC_ERR_ATA_BUS)
         return "ATA bus error";
     if (err_mask & AC_ERR_TIMEOUT)
         return "timeout";
     if (err_mask & AC_ERR_HSM)
         return "HSM violation";
     if (err_mask & AC_ERR_SYSTEM)
         return "internal error";
     if (err_mask & AC_ERR_MEDIA)
         return "media error";
     if (err_mask & AC_ERR_INVALID)
         return "invalid argument";
     if (err_mask & AC_ERR_DEV)
         return "device error";
     if (err_mask & AC_ERR_NCQ)
         return "NCQ error";
     if (err_mask & AC_ERR_NODEV_HINT)
         return "Polling detection error";
     return "unknown error";
 }
 
 /**
  *  atapi_eh_tur - perform ATAPI TEST_UNIT_READY
  *  @dev: target ATAPI device
  *  @r_sense_key: out parameter for sense_key
  *
  *  Perform ATAPI TEST_UNIT_READY.
  *
  *  LOCKING:
  *  EH context (may sleep).
  *
  *  RETURNS:
  *  0 on success, AC_ERR_* mask on failure.
  */
 unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
 {
     u8 cdb[ATAPI_CDB_LEN] = { TEST_UNIT_READY, 0, 0, 0, 0, 0 };
     struct ata_taskfile tf;
     unsigned int err_mask;
 
     ata_tf_init(dev, &tf);
 
     tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
     tf.command = ATA_CMD_PACKET;
     tf.protocol = ATAPI_PROT_NODATA;
 
     err_mask = ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
     if (err_mask == AC_ERR_DEV)
         *r_sense_key = tf.error >> 4;
     return err_mask;
 }
 
 /**
  *  ata_eh_request_sense - perform REQUEST_SENSE_DATA_EXT
  *  @qc: qc to perform REQUEST_SENSE_SENSE_DATA_EXT to
  *  @cmd: scsi command for which the sense code should be set
  *
  *  Perform REQUEST_SENSE_DATA_EXT after the device reported CHECK
  *  SENSE.  This function is an EH helper.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 static void ata_eh_request_sense(struct ata_queued_cmd *qc,
                  struct scsi_cmnd *cmd)
 {
     struct ata_device *dev = qc->dev;
     struct ata_taskfile tf;
     unsigned int err_mask;
 
     if (qc->ap->pflags & ATA_PFLAG_FROZEN) {
         ata_dev_warn(dev, "sense data available but port frozen\n");
         return;
     }
 
     if (!cmd || qc->flags & ATA_QCFLAG_SENSE_VALID)
         return;
 
     if (!ata_id_sense_reporting_enabled(dev->id)) {
         ata_dev_warn(qc->dev, "sense data reporting disabled\n");
         return;
     }
 
     ata_tf_init(dev, &tf);
     tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
     tf.flags |= ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
     tf.command = ATA_CMD_REQ_SENSE_DATA;
     tf.protocol = ATA_PROT_NODATA;
 
     err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
     /* Ignore err_mask; ATA_ERR might be set */
     if (tf.status & ATA_SENSE) {
         ata_scsi_set_sense(dev, cmd, tf.lbah, tf.lbam, tf.lbal);
         qc->flags |= ATA_QCFLAG_SENSE_VALID;
     } else {
         ata_dev_warn(dev, "request sense failed stat %02x emask %x\n",
                  tf.status, err_mask);
     }
 }
 
 /**
  *  atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
  *  @dev: device to perform REQUEST_SENSE to
  *  @sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
  *  @dfl_sense_key: default sense key to use
  *
  *  Perform ATAPI REQUEST_SENSE after the device reported CHECK
  *  SENSE.  This function is EH helper.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  *
  *  RETURNS:
  *  0 on success, AC_ERR_* mask on failure
  */
 unsigned int atapi_eh_request_sense(struct ata_device *dev,
                        u8 *sense_buf, u8 dfl_sense_key)
 {
     u8 cdb[ATAPI_CDB_LEN] =
         { REQUEST_SENSE, 0, 0, 0, SCSI_SENSE_BUFFERSIZE, 0 };
     struct ata_port *ap = dev->link->ap;
     struct ata_taskfile tf;
 
     memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);
 
     /* initialize sense_buf with the error register,
      * for the case where they are -not- overwritten
      */
     sense_buf[0] = 0x70;
     sense_buf[2] = dfl_sense_key;
 
     /* some devices time out if garbage left in tf */
     ata_tf_init(dev, &tf);
 
     tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
     tf.command = ATA_CMD_PACKET;
 
     /* is it pointless to prefer PIO for "safety reasons"? */
     if (ap->flags & ATA_FLAG_PIO_DMA) {
         tf.protocol = ATAPI_PROT_DMA;
         tf.feature |= ATAPI_PKT_DMA;
     } else {
         tf.protocol = ATAPI_PROT_PIO;
         tf.lbam = SCSI_SENSE_BUFFERSIZE;
         tf.lbah = 0;
     }
 
     return ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
                  sense_buf, SCSI_SENSE_BUFFERSIZE, 0);
 }
 
 /**
  *  ata_eh_analyze_serror - analyze SError for a failed port
  *  @link: ATA link to analyze SError for
  *
  *  Analyze SError if available and further determine cause of
  *  failure.
  *
  *  LOCKING:
  *  None.
  */
 static void ata_eh_analyze_serror(struct ata_link *link)
 {
     struct ata_eh_context *ehc = &link->eh_context;
     u32 serror = ehc->i.serror;
     unsigned int err_mask = 0, action = 0;
     u32 hotplug_mask;
 
     if (serror & (SERR_PERSISTENT | SERR_DATA)) {
         err_mask |= AC_ERR_ATA_BUS;
         action |= ATA_EH_RESET;
     }
     if (serror & SERR_PROTOCOL) {
         err_mask |= AC_ERR_HSM;
         action |= ATA_EH_RESET;
     }
     if (serror & SERR_INTERNAL) {
         err_mask |= AC_ERR_SYSTEM;
         action |= ATA_EH_RESET;
     }
 
     /* Determine whether a hotplug event has occurred.  Both
      * SError.N/X are considered hotplug events for enabled or
      * host links.  For disabled PMP links, only N bit is
      * considered as X bit is left at 1 for link plugging.
      */
     if (link->lpm_policy > ATA_LPM_MAX_POWER)
         hotplug_mask = 0;   /* hotplug doesn't work w/ LPM */
     else if (!(link->flags & ATA_LFLAG_DISABLED) || ata_is_host_link(link))
         hotplug_mask = SERR_PHYRDY_CHG | SERR_DEV_XCHG;
     else
         hotplug_mask = SERR_PHYRDY_CHG;
 
     if (serror & hotplug_mask)
         ata_ehi_hotplugged(&ehc->i);
 
     ehc->i.err_mask |= err_mask;
     ehc->i.action |= action;
 }
 
 /**
  *  ata_eh_analyze_tf - analyze taskfile of a failed qc
  *  @qc: qc to analyze
  *  @tf: Taskfile registers to analyze
  *
  *  Analyze taskfile of @qc and further determine cause of
  *  failure.  This function also requests ATAPI sense data if
  *  available.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  *
  *  RETURNS:
  *  Determined recovery action
  */
 static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
                       const struct ata_taskfile *tf)
 {
     unsigned int tmp, action = 0;
     u8 stat = tf->status, err = tf->error;
 
     if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
         qc->err_mask |= AC_ERR_HSM;
         return ATA_EH_RESET;
     }
 
     if (stat & (ATA_ERR | ATA_DF)) {
         qc->err_mask |= AC_ERR_DEV;
         /*
          * Sense data reporting does not work if the
          * device fault bit is set.
          */
         if (stat & ATA_DF)
             stat &= ~ATA_SENSE;
     } else {
         return 0;
     }
 
     switch (qc->dev->class) {
     case ATA_DEV_ZAC:
         if (stat & ATA_SENSE)
             ata_eh_request_sense(qc, qc->scsicmd);
         fallthrough;
     case ATA_DEV_ATA:
         if (err & ATA_ICRC)
             qc->err_mask |= AC_ERR_ATA_BUS;
         if (err & (ATA_UNC | ATA_AMNF))
             qc->err_mask |= AC_ERR_MEDIA;
         if (err & ATA_IDNF)
             qc->err_mask |= AC_ERR_INVALID;
         break;
 
     case ATA_DEV_ATAPI:
         if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
             tmp = atapi_eh_request_sense(qc->dev,
                         qc->scsicmd->sense_buffer,
                         qc->result_tf.error >> 4);
             if (!tmp)
                 qc->flags |= ATA_QCFLAG_SENSE_VALID;
             else
                 qc->err_mask |= tmp;
         }
     }
 
     if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
         enum scsi_disposition ret = scsi_check_sense(qc->scsicmd);
         /*
          * SUCCESS here means that the sense code could be
          * evaluated and should be passed to the upper layers
          * for correct evaluation.
          * FAILED means the sense code could not be interpreted
          * and the device would need to be reset.
          * NEEDS_RETRY and ADD_TO_MLQUEUE means that the
          * command would need to be retried.
          */
         if (ret == NEEDS_RETRY || ret == ADD_TO_MLQUEUE) {
             qc->flags |= ATA_QCFLAG_RETRY;
             qc->err_mask |= AC_ERR_OTHER;
         } else if (ret != SUCCESS) {
             qc->err_mask |= AC_ERR_HSM;
         }
     }
     if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
         action |= ATA_EH_RESET;
 
     return action;
 }
 
 static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
                    int *xfer_ok)
 {
     int base = 0;
 
     if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
         *xfer_ok = 1;
 
     if (!*xfer_ok)
         base = ATA_ECAT_DUBIOUS_NONE;
 
     if (err_mask & AC_ERR_ATA_BUS)
         return base + ATA_ECAT_ATA_BUS;
 
     if (err_mask & AC_ERR_TIMEOUT)
         return base + ATA_ECAT_TOUT_HSM;
 
     if (eflags & ATA_EFLAG_IS_IO) {
         if (err_mask & AC_ERR_HSM)
             return base + ATA_ECAT_TOUT_HSM;
         if ((err_mask &
              (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
             return base + ATA_ECAT_UNK_DEV;
     }
 
     return 0;
 }
 
 struct speed_down_verdict_arg {
     u64 since;
     int xfer_ok;
     int nr_errors[ATA_ECAT_NR];
 };
 
 static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
 {
     struct speed_down_verdict_arg *arg = void_arg;
     int cat;
 
     if ((ent->eflags & ATA_EFLAG_OLD_ER) || (ent->timestamp < arg->since))
         return -1;
 
     cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
                       &arg->xfer_ok);
     arg->nr_errors[cat]++;
 
     return 0;
 }
 
 /**
  *  ata_eh_speed_down_verdict - Determine speed down verdict
  *  @dev: Device of interest
  *
  *  This function examines error ring of @dev and determines
  *  whether NCQ needs to be turned off, transfer speed should be
  *  stepped down, or falling back to PIO is necessary.
  *
  *  ECAT_ATA_BUS    : ATA_BUS error for any command
  *
  *  ECAT_TOUT_HSM   : TIMEOUT for any command or HSM violation for
  *            IO commands
  *
  *  ECAT_UNK_DEV    : Unknown DEV error for IO commands
  *
  *  ECAT_DUBIOUS_*  : Identical to above three but occurred while
  *            data transfer hasn't been verified.
  *
  *  Verdicts are
  *
  *  NCQ_OFF     : Turn off NCQ.
  *
  *  SPEED_DOWN  : Speed down transfer speed but don't fall back
  *            to PIO.
  *
  *  FALLBACK_TO_PIO : Fall back to PIO.
  *
  *  Even if multiple verdicts are returned, only one action is
  *  taken per error.  An action triggered by non-DUBIOUS errors
  *  clears ering, while one triggered by DUBIOUS_* errors doesn't.
  *  This is to expedite speed down decisions right after device is
  *  initially configured.
  *
  *  The following are speed down rules.  #1 and #2 deal with
  *  DUBIOUS errors.
  *
  *  1. If more than one DUBIOUS_ATA_BUS or DUBIOUS_TOUT_HSM errors
  *     occurred during last 5 mins, SPEED_DOWN and FALLBACK_TO_PIO.
  *
  *  2. If more than one DUBIOUS_TOUT_HSM or DUBIOUS_UNK_DEV errors
  *     occurred during last 5 mins, NCQ_OFF.
  *
  *  3. If more than 8 ATA_BUS, TOUT_HSM or UNK_DEV errors
  *     occurred during last 5 mins, FALLBACK_TO_PIO
  *
  *  4. If more than 3 TOUT_HSM or UNK_DEV errors occurred
  *     during last 10 mins, NCQ_OFF.
  *
  *  5. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
  *     UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
  *
  *  LOCKING:
  *  Inherited from caller.
  *
  *  RETURNS:
  *  OR of ATA_EH_SPDN_* flags.
  */
 static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
 {
     const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
     u64 j64 = get_jiffies_64();
     struct speed_down_verdict_arg arg;
     unsigned int verdict = 0;
 
     /* scan past 5 mins of error history */
     memset(&arg, 0, sizeof(arg));
     arg.since = j64 - min(j64, j5mins);
     ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
 
     if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
         arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
         verdict |= ATA_EH_SPDN_SPEED_DOWN |
             ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;
 
     if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
         arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
         verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;
 
     if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
         arg.nr_errors[ATA_ECAT_TOUT_HSM] +
         arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
         verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
 
     /* scan past 10 mins of error history */
     memset(&arg, 0, sizeof(arg));
     arg.since = j64 - min(j64, j10mins);
     ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
 
     if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
         arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
         verdict |= ATA_EH_SPDN_NCQ_OFF;
 
     if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
         arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
         arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
         verdict |= ATA_EH_SPDN_SPEED_DOWN;
 
     return verdict;
 }
 
 /**
  *  ata_eh_speed_down - record error and speed down if necessary
  *  @dev: Failed device
  *  @eflags: mask of ATA_EFLAG_* flags
  *  @err_mask: err_mask of the error
  *
  *  Record error and examine error history to determine whether
  *  adjusting transmission speed is necessary.  It also sets
  *  transmission limits appropriately if such adjustment is
  *  necessary.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  *
  *  RETURNS:
  *  Determined recovery action.
  */
 static unsigned int ata_eh_speed_down(struct ata_device *dev,
                 unsigned int eflags, unsigned int err_mask)
 {
     struct ata_link *link = ata_dev_phys_link(dev);
     int xfer_ok = 0;
     unsigned int verdict;
     unsigned int action = 0;
 
     /* don't bother if Cat-0 error */
     if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
         return 0;
 
     /* record error and determine whether speed down is necessary */
     ata_ering_record(&dev->ering, eflags, err_mask);
     verdict = ata_eh_speed_down_verdict(dev);
 
     /* turn off NCQ? */
     if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
         (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
                ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
         dev->flags |= ATA_DFLAG_NCQ_OFF;
         ata_dev_warn(dev, "NCQ disabled due to excessive errors\n");
         goto done;
     }
 
     /* speed down? */
     if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
         /* speed down SATA link speed if possible */
         if (sata_down_spd_limit(link, 0) == 0) {
             action |= ATA_EH_RESET;
             goto done;
         }
 
         /* lower transfer mode */
         if (dev->spdn_cnt < 2) {
             static const int dma_dnxfer_sel[] =
                 { ATA_DNXFER_DMA, ATA_DNXFER_40C };
             static const int pio_dnxfer_sel[] =
                 { ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
             int sel;
 
             if (dev->xfer_shift != ATA_SHIFT_PIO)
                 sel = dma_dnxfer_sel[dev->spdn_cnt];
             else
                 sel = pio_dnxfer_sel[dev->spdn_cnt];
 
             dev->spdn_cnt++;
 
             if (ata_down_xfermask_limit(dev, sel) == 0) {
                 action |= ATA_EH_RESET;
                 goto done;
             }
         }
     }
 
     /* Fall back to PIO?  Slowing down to PIO is meaningless for
      * SATA ATA devices.  Consider it only for PATA and SATAPI.
      */
     if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
         (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
         (dev->xfer_shift != ATA_SHIFT_PIO)) {
         if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
             dev->spdn_cnt = 0;
             action |= ATA_EH_RESET;
             goto done;
         }
     }
 
     return 0;
  done:
     /* device has been slowed down, blow error history */
     if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
         ata_ering_clear(&dev->ering);
     return action;
 }
 
 /**
  *  ata_eh_worth_retry - analyze error and decide whether to retry
  *  @qc: qc to possibly retry
  *
  *  Look at the cause of the error and decide if a retry
  *  might be useful or not.  We don't want to retry media errors
  *  because the drive itself has probably already taken 10-30 seconds
  *  doing its own internal retries before reporting the failure.
  */
 static inline int ata_eh_worth_retry(struct ata_queued_cmd *qc)
 {
     if (qc->err_mask & AC_ERR_MEDIA)
         return 0;   /* don't retry media errors */
     if (qc->flags & ATA_QCFLAG_IO)
         return 1;   /* otherwise retry anything from fs stack */
     if (qc->err_mask & AC_ERR_INVALID)
         return 0;   /* don't retry these */
     return qc->err_mask != AC_ERR_DEV;  /* retry if not dev error */
 }
 
 /**
  *      ata_eh_quiet - check if we need to be quiet about a command error
  *      @qc: qc to check
  *
  *      Look at the qc flags anbd its scsi command request flags to determine
  *      if we need to be quiet about the command failure.
  */
 static inline bool ata_eh_quiet(struct ata_queued_cmd *qc)
 {
     if (qc->scsicmd && scsi_cmd_to_rq(qc->scsicmd)->rq_flags & RQF_QUIET)
         qc->flags |= ATA_QCFLAG_QUIET;
     return qc->flags & ATA_QCFLAG_QUIET;
 }
 
 /**
  *  ata_eh_link_autopsy - analyze error and determine recovery action
  *  @link: host link to perform autopsy on
  *
  *  Analyze why @link failed and determine which recovery actions
  *  are needed.  This function also sets more detailed AC_ERR_*
  *  values and fills sense data for ATAPI CHECK SENSE.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 static void ata_eh_link_autopsy(struct ata_link *link)
 {
     struct ata_port *ap = link->ap;
     struct ata_eh_context *ehc = &link->eh_context;
     struct ata_queued_cmd *qc;
     struct ata_device *dev;
     unsigned int all_err_mask = 0, eflags = 0;
     int tag, nr_failed = 0, nr_quiet = 0;
     u32 serror;
     int rc;
 
     if (ehc->i.flags & ATA_EHI_NO_AUTOPSY)
         return;
 
     /* obtain and analyze SError */
     rc = sata_scr_read(link, SCR_ERROR, &serror);
     if (rc == 0) {
         ehc->i.serror |= serror;
         ata_eh_analyze_serror(link);
     } else if (rc != -EOPNOTSUPP) {
         /* SError read failed, force reset and probing */
         ehc->i.probe_mask |= ATA_ALL_DEVICES;
         ehc->i.action |= ATA_EH_RESET;
         ehc->i.err_mask |= AC_ERR_OTHER;
     }
 
     /* analyze NCQ failure */
     ata_eh_analyze_ncq_error(link);
 
     /* any real error trumps AC_ERR_OTHER */
     if (ehc->i.err_mask & ~AC_ERR_OTHER)
         ehc->i.err_mask &= ~AC_ERR_OTHER;
 
     all_err_mask |= ehc->i.err_mask;
 
     ata_qc_for_each_raw(ap, qc, tag) {
         if (!(qc->flags & ATA_QCFLAG_FAILED) ||
             ata_dev_phys_link(qc->dev) != link)
             continue;
 
         /* inherit upper level err_mask */
         qc->err_mask |= ehc->i.err_mask;
 
         /* analyze TF */
         ehc->i.action |= ata_eh_analyze_tf(qc, &qc->result_tf);
 
         /* DEV errors are probably spurious in case of ATA_BUS error */
         if (qc->err_mask & AC_ERR_ATA_BUS)
             qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA |
                       AC_ERR_INVALID);
 
         /* any real error trumps unknown error */
         if (qc->err_mask & ~AC_ERR_OTHER)
             qc->err_mask &= ~AC_ERR_OTHER;
 
         /*
          * SENSE_VALID trumps dev/unknown error and revalidation. Upper
          * layers will determine whether the command is worth retrying
          * based on the sense data and device class/type. Otherwise,
          * determine directly if the command is worth retrying using its
          * error mask and flags.
          */
         if (qc->flags & ATA_QCFLAG_SENSE_VALID)
             qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);
         else if (ata_eh_worth_retry(qc))
             qc->flags |= ATA_QCFLAG_RETRY;
 
         /* accumulate error info */
         ehc->i.dev = qc->dev;
         all_err_mask |= qc->err_mask;
         if (qc->flags & ATA_QCFLAG_IO)
             eflags |= ATA_EFLAG_IS_IO;
         trace_ata_eh_link_autopsy_qc(qc);
 
         /* Count quiet errors */
         if (ata_eh_quiet(qc))
             nr_quiet++;
         nr_failed++;
     }
 
     /* If all failed commands requested silence, then be quiet */
     if (nr_quiet == nr_failed)
         ehc->i.flags |= ATA_EHI_QUIET;
 
     /* enforce default EH actions */
     if (ap->pflags & ATA_PFLAG_FROZEN ||
         all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
         ehc->i.action |= ATA_EH_RESET;
     else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
          (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
         ehc->i.action |= ATA_EH_REVALIDATE;
 
     /* If we have offending qcs and the associated failed device,
      * perform per-dev EH action only on the offending device.
      */
     if (ehc->i.dev) {
         ehc->i.dev_action[ehc->i.dev->devno] |=
             ehc->i.action & ATA_EH_PERDEV_MASK;
         ehc->i.action &= ~ATA_EH_PERDEV_MASK;
     }
 
     /* propagate timeout to host link */
     if ((all_err_mask & AC_ERR_TIMEOUT) && !ata_is_host_link(link))
         ap->link.eh_context.i.err_mask |= AC_ERR_TIMEOUT;
 
     /* record error and consider speeding down */
     dev = ehc->i.dev;
     if (!dev && ((ata_link_max_devices(link) == 1 &&
               ata_dev_enabled(link->device))))
         dev = link->device;
 
     if (dev) {
         if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
             eflags |= ATA_EFLAG_DUBIOUS_XFER;
         ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
         trace_ata_eh_link_autopsy(dev, ehc->i.action, all_err_mask);
     }
 }
 
 /**
  *  ata_eh_autopsy - analyze error and determine recovery action
  *  @ap: host port to perform autopsy on
  *
  *  Analyze all links of @ap and determine why they failed and
  *  which recovery actions are needed.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 void ata_eh_autopsy(struct ata_port *ap)
 {
     struct ata_link *link;
 
     ata_for_each_link(link, ap, EDGE)
         ata_eh_link_autopsy(link);
 
     /* Handle the frigging slave link.  Autopsy is done similarly
      * but actions and flags are transferred over to the master
      * link and handled from there.
      */
     if (ap->slave_link) {
         struct ata_eh_context *mehc = &ap->link.eh_context;
         struct ata_eh_context *sehc = &ap->slave_link->eh_context;
 
         /* transfer control flags from master to slave */
         sehc->i.flags |= mehc->i.flags & ATA_EHI_TO_SLAVE_MASK;
 
         /* perform autopsy on the slave link */
         ata_eh_link_autopsy(ap->slave_link);
 
         /* transfer actions from slave to master and clear slave */
         ata_eh_about_to_do(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
         mehc->i.action      |= sehc->i.action;
         mehc->i.dev_action[1]   |= sehc->i.dev_action[1];
         mehc->i.flags       |= sehc->i.flags;
         ata_eh_done(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
     }
 
     /* Autopsy of fanout ports can affect host link autopsy.
      * Perform host link autopsy last.
      */
     if (sata_pmp_attached(ap))
         ata_eh_link_autopsy(&ap->link);
 }
 
 /**
  *  ata_get_cmd_name - get name for ATA command
  *  @command: ATA command code to get name for
  *
  *  Return a textual name of the given command or "unknown"
  *
  *  LOCKING:
  *  None
  */
 const char *ata_get_cmd_name(u8 command)
 {
 #ifdef CONFIG_ATA_VERBOSE_ERROR
     static const struct
     {
         u8 command;
         const char *text;
     } cmd_descr[] = {
         { ATA_CMD_DEV_RESET,        "DEVICE RESET" },
         { ATA_CMD_CHK_POWER,        "CHECK POWER MODE" },
         { ATA_CMD_STANDBY,      "STANDBY" },
         { ATA_CMD_IDLE,         "IDLE" },
         { ATA_CMD_EDD,          "EXECUTE DEVICE DIAGNOSTIC" },
         { ATA_CMD_DOWNLOAD_MICRO,   "DOWNLOAD MICROCODE" },
         { ATA_CMD_DOWNLOAD_MICRO_DMA,   "DOWNLOAD MICROCODE DMA" },
         { ATA_CMD_NOP,          "NOP" },
         { ATA_CMD_FLUSH,        "FLUSH CACHE" },
         { ATA_CMD_FLUSH_EXT,        "FLUSH CACHE EXT" },
         { ATA_CMD_ID_ATA,       "IDENTIFY DEVICE" },
         { ATA_CMD_ID_ATAPI,     "IDENTIFY PACKET DEVICE" },
         { ATA_CMD_SERVICE,      "SERVICE" },
         { ATA_CMD_READ,         "READ DMA" },
         { ATA_CMD_READ_EXT,     "READ DMA EXT" },
         { ATA_CMD_READ_QUEUED,      "READ DMA QUEUED" },
         { ATA_CMD_READ_STREAM_EXT,  "READ STREAM EXT" },
         { ATA_CMD_READ_STREAM_DMA_EXT,  "READ STREAM DMA EXT" },
         { ATA_CMD_WRITE,        "WRITE DMA" },
         { ATA_CMD_WRITE_EXT,        "WRITE DMA EXT" },
         { ATA_CMD_WRITE_QUEUED,     "WRITE DMA QUEUED EXT" },
         { ATA_CMD_WRITE_STREAM_EXT, "WRITE STREAM EXT" },
         { ATA_CMD_WRITE_STREAM_DMA_EXT, "WRITE STREAM DMA EXT" },
         { ATA_CMD_WRITE_FUA_EXT,    "WRITE DMA FUA EXT" },
         { ATA_CMD_WRITE_QUEUED_FUA_EXT, "WRITE DMA QUEUED FUA EXT" },
         { ATA_CMD_FPDMA_READ,       "READ FPDMA QUEUED" },
         { ATA_CMD_FPDMA_WRITE,      "WRITE FPDMA QUEUED" },
         { ATA_CMD_NCQ_NON_DATA,     "NCQ NON-DATA" },
         { ATA_CMD_FPDMA_SEND,       "SEND FPDMA QUEUED" },
         { ATA_CMD_FPDMA_RECV,       "RECEIVE FPDMA QUEUED" },
         { ATA_CMD_PIO_READ,     "READ SECTOR(S)" },
         { ATA_CMD_PIO_READ_EXT,     "READ SECTOR(S) EXT" },
         { ATA_CMD_PIO_WRITE,        "WRITE SECTOR(S)" },
         { ATA_CMD_PIO_WRITE_EXT,    "WRITE SECTOR(S) EXT" },
         { ATA_CMD_READ_MULTI,       "READ MULTIPLE" },
         { ATA_CMD_READ_MULTI_EXT,   "READ MULTIPLE EXT" },
         { ATA_CMD_WRITE_MULTI,      "WRITE MULTIPLE" },
         { ATA_CMD_WRITE_MULTI_EXT,  "WRITE MULTIPLE EXT" },
         { ATA_CMD_WRITE_MULTI_FUA_EXT,  "WRITE MULTIPLE FUA EXT" },
         { ATA_CMD_SET_FEATURES,     "SET FEATURES" },
         { ATA_CMD_SET_MULTI,        "SET MULTIPLE MODE" },
         { ATA_CMD_VERIFY,       "READ VERIFY SECTOR(S)" },
         { ATA_CMD_VERIFY_EXT,       "READ VERIFY SECTOR(S) EXT" },
         { ATA_CMD_WRITE_UNCORR_EXT, "WRITE UNCORRECTABLE EXT" },
         { ATA_CMD_STANDBYNOW1,      "STANDBY IMMEDIATE" },
         { ATA_CMD_IDLEIMMEDIATE,    "IDLE IMMEDIATE" },
         { ATA_CMD_SLEEP,        "SLEEP" },
         { ATA_CMD_INIT_DEV_PARAMS,  "INITIALIZE DEVICE PARAMETERS" },
         { ATA_CMD_READ_NATIVE_MAX,  "READ NATIVE MAX ADDRESS" },
         { ATA_CMD_READ_NATIVE_MAX_EXT,  "READ NATIVE MAX ADDRESS EXT" },
         { ATA_CMD_SET_MAX,      "SET MAX ADDRESS" },
         { ATA_CMD_SET_MAX_EXT,      "SET MAX ADDRESS EXT" },
         { ATA_CMD_READ_LOG_EXT,     "READ LOG EXT" },
         { ATA_CMD_WRITE_LOG_EXT,    "WRITE LOG EXT" },
         { ATA_CMD_READ_LOG_DMA_EXT, "READ LOG DMA EXT" },
         { ATA_CMD_WRITE_LOG_DMA_EXT,    "WRITE LOG DMA EXT" },
         { ATA_CMD_TRUSTED_NONDATA,  "TRUSTED NON-DATA" },
         { ATA_CMD_TRUSTED_RCV,      "TRUSTED RECEIVE" },
         { ATA_CMD_TRUSTED_RCV_DMA,  "TRUSTED RECEIVE DMA" },
         { ATA_CMD_TRUSTED_SND,      "TRUSTED SEND" },
         { ATA_CMD_TRUSTED_SND_DMA,  "TRUSTED SEND DMA" },
         { ATA_CMD_PMP_READ,     "READ BUFFER" },
         { ATA_CMD_PMP_READ_DMA,     "READ BUFFER DMA" },
         { ATA_CMD_PMP_WRITE,        "WRITE BUFFER" },
         { ATA_CMD_PMP_WRITE_DMA,    "WRITE BUFFER DMA" },
         { ATA_CMD_CONF_OVERLAY,     "DEVICE CONFIGURATION OVERLAY" },
         { ATA_CMD_SEC_SET_PASS,     "SECURITY SET PASSWORD" },
         { ATA_CMD_SEC_UNLOCK,       "SECURITY UNLOCK" },
         { ATA_CMD_SEC_ERASE_PREP,   "SECURITY ERASE PREPARE" },
         { ATA_CMD_SEC_ERASE_UNIT,   "SECURITY ERASE UNIT" },
         { ATA_CMD_SEC_FREEZE_LOCK,  "SECURITY FREEZE LOCK" },
         { ATA_CMD_SEC_DISABLE_PASS, "SECURITY DISABLE PASSWORD" },
         { ATA_CMD_CONFIG_STREAM,    "CONFIGURE STREAM" },
         { ATA_CMD_SMART,        "SMART" },
         { ATA_CMD_MEDIA_LOCK,       "DOOR LOCK" },
         { ATA_CMD_MEDIA_UNLOCK,     "DOOR UNLOCK" },
         { ATA_CMD_DSM,          "DATA SET MANAGEMENT" },
         { ATA_CMD_CHK_MED_CRD_TYP,  "CHECK MEDIA CARD TYPE" },
         { ATA_CMD_CFA_REQ_EXT_ERR,  "CFA REQUEST EXTENDED ERROR" },
         { ATA_CMD_CFA_WRITE_NE,     "CFA WRITE SECTORS WITHOUT ERASE" },
         { ATA_CMD_CFA_TRANS_SECT,   "CFA TRANSLATE SECTOR" },
         { ATA_CMD_CFA_ERASE,        "CFA ERASE SECTORS" },
         { ATA_CMD_CFA_WRITE_MULT_NE,    "CFA WRITE MULTIPLE WITHOUT ERASE" },
         { ATA_CMD_REQ_SENSE_DATA,   "REQUEST SENSE DATA EXT" },
         { ATA_CMD_SANITIZE_DEVICE,  "SANITIZE DEVICE" },
         { ATA_CMD_ZAC_MGMT_IN,      "ZAC MANAGEMENT IN" },
         { ATA_CMD_ZAC_MGMT_OUT,     "ZAC MANAGEMENT OUT" },
         { ATA_CMD_READ_LONG,        "READ LONG (with retries)" },
         { ATA_CMD_READ_LONG_ONCE,   "READ LONG (without retries)" },
         { ATA_CMD_WRITE_LONG,       "WRITE LONG (with retries)" },
         { ATA_CMD_WRITE_LONG_ONCE,  "WRITE LONG (without retries)" },
         { ATA_CMD_RESTORE,      "RECALIBRATE" },
         { 0,                NULL } /* terminate list */
     };
 
     unsigned int i;
     for (i = 0; cmd_descr[i].text; i++)
         if (cmd_descr[i].command == command)
             return cmd_descr[i].text;
 #endif
 
     return "unknown";
 }
 EXPORT_SYMBOL_GPL(ata_get_cmd_name);
 
 /**
  *  ata_eh_link_report - report error handling to user
  *  @link: ATA link EH is going on
  *
  *  Report EH to user.
  *
  *  LOCKING:
  *  None.
  */
 static void ata_eh_link_report(struct ata_link *link)
 {
     struct ata_port *ap = link->ap;
     struct ata_eh_context *ehc = &link->eh_context;
     struct ata_queued_cmd *qc;
     const char *frozen, *desc;
     char tries_buf[6] = "";
     int tag, nr_failed = 0;
 
     if (ehc->i.flags & ATA_EHI_QUIET)
         return;
 
     desc = NULL;
     if (ehc->i.desc[0] != '\0')
         desc = ehc->i.desc;
 
     ata_qc_for_each_raw(ap, qc, tag) {
         if (!(qc->flags & ATA_QCFLAG_FAILED) ||
             ata_dev_phys_link(qc->dev) != link ||
             ((qc->flags & ATA_QCFLAG_QUIET) &&
              qc->err_mask == AC_ERR_DEV))
             continue;
         if (qc->flags & ATA_QCFLAG_SENSE_VALID && !qc->err_mask)
             continue;
 
         nr_failed++;
     }
 
     if (!nr_failed && !ehc->i.err_mask)
         return;
 
     frozen = "";
     if (ap->pflags & ATA_PFLAG_FROZEN)
         frozen = " frozen";
 
     if (ap->eh_tries < ATA_EH_MAX_TRIES)
         snprintf(tries_buf, sizeof(tries_buf), " t%d",
              ap->eh_tries);
 
     if (ehc->i.dev) {
         ata_dev_err(ehc->i.dev, "exception Emask 0x%x "
                 "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
                 ehc->i.err_mask, link->sactive, ehc->i.serror,
                 ehc->i.action, frozen, tries_buf);
         if (desc)
             ata_dev_err(ehc->i.dev, "%s\n", desc);
     } else {
         ata_link_err(link, "exception Emask 0x%x "
                  "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
                  ehc->i.err_mask, link->sactive, ehc->i.serror,
                  ehc->i.action, frozen, tries_buf);
         if (desc)
             ata_link_err(link, "%s\n", desc);
     }
 
 #ifdef CONFIG_ATA_VERBOSE_ERROR
     if (ehc->i.serror)
         ata_link_err(link,
           "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
           ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
           ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
           ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
           ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
           ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
           ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
           ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
           ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
           ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
           ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
           ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
           ehc->i.serror & SERR_CRC ? "BadCRC " : "",
           ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
           ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
           ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
           ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
           ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "");
 #endif
 
     ata_qc_for_each_raw(ap, qc, tag) {
         struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
         char data_buf[20] = "";
         char cdb_buf[70] = "";
 
         if (!(qc->flags & ATA_QCFLAG_FAILED) ||
             ata_dev_phys_link(qc->dev) != link || !qc->err_mask)
             continue;
 
         if (qc->dma_dir != DMA_NONE) {
             static const char *dma_str[] = {
                 [DMA_BIDIRECTIONAL] = "bidi",
                 [DMA_TO_DEVICE]     = "out",
                 [DMA_FROM_DEVICE]   = "in",
             };
             const char *prot_str = NULL;
 
             switch (qc->tf.protocol) {
             case ATA_PROT_UNKNOWN:
                 prot_str = "unknown";
                 break;
             case ATA_PROT_NODATA:
                 prot_str = "nodata";
                 break;
             case ATA_PROT_PIO:
                 prot_str = "pio";
                 break;
             case ATA_PROT_DMA:
                 prot_str = "dma";
                 break;
             case ATA_PROT_NCQ:
                 prot_str = "ncq dma";
                 break;
             case ATA_PROT_NCQ_NODATA:
                 prot_str = "ncq nodata";
                 break;
             case ATAPI_PROT_NODATA:
                 prot_str = "nodata";
                 break;
             case ATAPI_PROT_PIO:
                 prot_str = "pio";
                 break;
             case ATAPI_PROT_DMA:
                 prot_str = "dma";
                 break;
             }
             snprintf(data_buf, sizeof(data_buf), " %s %u %s",
                  prot_str, qc->nbytes, dma_str[qc->dma_dir]);
         }
 
         if (ata_is_atapi(qc->tf.protocol)) {
             const u8 *cdb = qc->cdb;
             size_t cdb_len = qc->dev->cdb_len;
 
             if (qc->scsicmd) {
                 cdb = qc->scsicmd->cmnd;
                 cdb_len = qc->scsicmd->cmd_len;
             }
             __scsi_format_command(cdb_buf, sizeof(cdb_buf),
                           cdb, cdb_len);
         } else
             ata_dev_err(qc->dev, "failed command: %s\n",
                     ata_get_cmd_name(cmd->command));
 
         ata_dev_err(qc->dev,
             "cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
             "tag %d%s\n         %s"
             "res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
             "Emask 0x%x (%s)%s\n",
             cmd->command, cmd->feature, cmd->nsect,
             cmd->lbal, cmd->lbam, cmd->lbah,
             cmd->hob_feature, cmd->hob_nsect,
             cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
             cmd->device, qc->tag, data_buf, cdb_buf,
             res->status, res->error, res->nsect,
             res->lbal, res->lbam, res->lbah,
             res->hob_feature, res->hob_nsect,
             res->hob_lbal, res->hob_lbam, res->hob_lbah,
             res->device, qc->err_mask, ata_err_string(qc->err_mask),
             qc->err_mask & AC_ERR_NCQ ? " <F>" : "");
 
 #ifdef CONFIG_ATA_VERBOSE_ERROR
         if (res->status & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
                    ATA_SENSE | ATA_ERR)) {
             if (res->status & ATA_BUSY)
                 ata_dev_err(qc->dev, "status: { Busy }\n");
             else
                 ata_dev_err(qc->dev, "status: { %s%s%s%s%s}\n",
                   res->status & ATA_DRDY ? "DRDY " : "",
                   res->status & ATA_DF ? "DF " : "",
                   res->status & ATA_DRQ ? "DRQ " : "",
                   res->status & ATA_SENSE ? "SENSE " : "",
                   res->status & ATA_ERR ? "ERR " : "");
         }
 
         if (cmd->command != ATA_CMD_PACKET &&
             (res->error & (ATA_ICRC | ATA_UNC | ATA_AMNF | ATA_IDNF |
                    ATA_ABORTED)))
             ata_dev_err(qc->dev, "error: { %s%s%s%s%s}\n",
                     res->error & ATA_ICRC ? "ICRC " : "",
                     res->error & ATA_UNC ? "UNC " : "",
                     res->error & ATA_AMNF ? "AMNF " : "",
                     res->error & ATA_IDNF ? "IDNF " : "",
                     res->error & ATA_ABORTED ? "ABRT " : "");
 #endif
     }
 }
 
 /**
  *  ata_eh_report - report error handling to user
  *  @ap: ATA port to report EH about
  *
  *  Report EH to user.
  *
  *  LOCKING:
  *  None.
  */
 void ata_eh_report(struct ata_port *ap)
 {
     struct ata_link *link;
 
     ata_for_each_link(link, ap, HOST_FIRST)
         ata_eh_link_report(link);
 }
 
 static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
             unsigned int *classes, unsigned long deadline,
             bool clear_classes)
 {
     struct ata_device *dev;
 
     if (clear_classes)
         ata_for_each_dev(dev, link, ALL)
             classes[dev->devno] = ATA_DEV_UNKNOWN;
 
     return reset(link, classes, deadline);
 }
 
 static int ata_eh_followup_srst_needed(struct ata_link *link, int rc)
 {
     if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
         return 0;
     if (rc == -EAGAIN)
         return 1;
     if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
         return 1;
     return 0;
 }
 
 int ata_eh_reset(struct ata_link *link, int classify,
          ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
          ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
 {
     struct ata_port *ap = link->ap;
     struct ata_link *slave = ap->slave_link;
     struct ata_eh_context *ehc = &link->eh_context;
     struct ata_eh_context *sehc = slave ? &slave->eh_context : NULL;
     unsigned int *classes = ehc->classes;
     unsigned int lflags = link->flags;
     int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
     int max_tries = 0, try = 0;
     struct ata_link *failed_link;
     struct ata_device *dev;
     unsigned long deadline, now;
     ata_reset_fn_t reset;
     unsigned long flags;
     u32 sstatus;
     int nr_unknown, rc;
 
     /*
      * Prepare to reset
      */
     while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
         max_tries++;
     if (link->flags & ATA_LFLAG_RST_ONCE)
         max_tries = 1;
     if (link->flags & ATA_LFLAG_NO_HRST)
         hardreset = NULL;
     if (link->flags & ATA_LFLAG_NO_SRST)
         softreset = NULL;
 
     /* make sure each reset attempt is at least COOL_DOWN apart */
     if (ehc->i.flags & ATA_EHI_DID_RESET) {
         now = jiffies;
         WARN_ON(time_after(ehc->last_reset, now));
         deadline = ata_deadline(ehc->last_reset,
                     ATA_EH_RESET_COOL_DOWN);
         if (time_before(now, deadline))
             schedule_timeout_uninterruptible(deadline - now);
     }
 
     spin_lock_irqsave(ap->lock, flags);
     ap->pflags |= ATA_PFLAG_RESETTING;
     spin_unlock_irqrestore(ap->lock, flags);
 
     ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
 
     ata_for_each_dev(dev, link, ALL) {
         /* If we issue an SRST then an ATA drive (not ATAPI)
          * may change configuration and be in PIO0 timing. If
          * we do a hard reset (or are coming from power on)
          * this is true for ATA or ATAPI. Until we've set a
          * suitable controller mode we should not touch the
          * bus as we may be talking too fast.
          */
         dev->pio_mode = XFER_PIO_0;
         dev->dma_mode = 0xff;
 
         /* If the controller has a pio mode setup function
          * then use it to set the chipset to rights. Don't
          * touch the DMA setup as that will be dealt with when
          * configuring devices.
          */
         if (ap->ops->set_piomode)
             ap->ops->set_piomode(ap, dev);
     }
 
     /* prefer hardreset */
     reset = NULL;
     ehc->i.action &= ~ATA_EH_RESET;
     if (hardreset) {
         reset = hardreset;
         ehc->i.action |= ATA_EH_HARDRESET;
     } else if (softreset) {
         reset = softreset;
         ehc->i.action |= ATA_EH_SOFTRESET;
     }
 
     if (prereset) {
         unsigned long deadline = ata_deadline(jiffies,
                               ATA_EH_PRERESET_TIMEOUT);
 
         if (slave) {
             sehc->i.action &= ~ATA_EH_RESET;
             sehc->i.action |= ehc->i.action;
         }
 
         rc = prereset(link, deadline);
 
         /* If present, do prereset on slave link too.  Reset
          * is skipped iff both master and slave links report
          * -ENOENT or clear ATA_EH_RESET.
          */
         if (slave && (rc == 0 || rc == -ENOENT)) {
             int tmp;
 
             tmp = prereset(slave, deadline);
             if (tmp != -ENOENT)
                 rc = tmp;
 
             ehc->i.action |= sehc->i.action;
         }
 
         if (rc) {
             if (rc == -ENOENT) {
                 ata_link_dbg(link, "port disabled--ignoring\n");
                 ehc->i.action &= ~ATA_EH_RESET;
 
                 ata_for_each_dev(dev, link, ALL)
                     classes[dev->devno] = ATA_DEV_NONE;
 
                 rc = 0;
             } else
                 ata_link_err(link,
                          "prereset failed (errno=%d)\n",
                          rc);
             goto out;
         }
 
         /* prereset() might have cleared ATA_EH_RESET.  If so,
          * bang classes, thaw and return.
          */
         if (reset && !(ehc->i.action & ATA_EH_RESET)) {
             ata_for_each_dev(dev, link, ALL)
                 classes[dev->devno] = ATA_DEV_NONE;
             if ((ap->pflags & ATA_PFLAG_FROZEN) &&
                 ata_is_host_link(link))
                 ata_eh_thaw_port(ap);
             rc = 0;
             goto out;
         }
     }
 
  retry:
     /*
      * Perform reset
      */
     if (ata_is_host_link(link))
         ata_eh_freeze_port(ap);
 
     deadline = ata_deadline(jiffies, ata_eh_reset_timeouts[try++]);
 
     if (reset) {
         if (verbose)
             ata_link_info(link, "%s resetting link\n",
                       reset == softreset ? "soft" : "hard");
 
         /* mark that this EH session started with reset */
         ehc->last_reset = jiffies;
         if (reset == hardreset) {
             ehc->i.flags |= ATA_EHI_DID_HARDRESET;
             trace_ata_link_hardreset_begin(link, classes, deadline);
         } else {
             ehc->i.flags |= ATA_EHI_DID_SOFTRESET;
             trace_ata_link_softreset_begin(link, classes, deadline);
         }
 
         rc = ata_do_reset(link, reset, classes, deadline, true);
         if (reset == hardreset)
             trace_ata_link_hardreset_end(link, classes, rc);
         else
             trace_ata_link_softreset_end(link, classes, rc);
         if (rc && rc != -EAGAIN) {
             failed_link = link;
             goto fail;
         }
 
         /* hardreset slave link if existent */
         if (slave && reset == hardreset) {
             int tmp;
 
             if (verbose)
                 ata_link_info(slave, "hard resetting link\n");
 
             ata_eh_about_to_do(slave, NULL, ATA_EH_RESET);
             trace_ata_slave_hardreset_begin(slave, classes,
                             deadline);
             tmp = ata_do_reset(slave, reset, classes, deadline,
                        false);
             trace_ata_slave_hardreset_end(slave, classes, tmp);
             switch (tmp) {
             case -EAGAIN:
                 rc = -EAGAIN;
                 break;
             case 0:
                 break;
             default:
                 failed_link = slave;
                 rc = tmp;
                 goto fail;
             }
         }
 
         /* perform follow-up SRST if necessary */
         if (reset == hardreset &&
             ata_eh_followup_srst_needed(link, rc)) {
             reset = softreset;
 
             if (!reset) {
                 ata_link_err(link,
          "follow-up softreset required but no softreset available\n");
                 failed_link = link;
                 rc = -EINVAL;
                 goto fail;
             }
 
             ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
             trace_ata_link_softreset_begin(link, classes, deadline);
             rc = ata_do_reset(link, reset, classes, deadline, true);
             trace_ata_link_softreset_end(link, classes, rc);
             if (rc) {
                 failed_link = link;
                 goto fail;
             }
         }
     } else {
         if (verbose)
             ata_link_info(link,
     "no reset method available, skipping reset\n");
         if (!(lflags & ATA_LFLAG_ASSUME_CLASS))
             lflags |= ATA_LFLAG_ASSUME_ATA;
     }
 
     /*
      * Post-reset processing
      */
     ata_for_each_dev(dev, link, ALL) {
         /* After the reset, the device state is PIO 0 and the
          * controller state is undefined.  Reset also wakes up
          * drives from sleeping mode.
          */
         dev->pio_mode = XFER_PIO_0;
         dev->flags &= ~ATA_DFLAG_SLEEPING;
 
         if (ata_phys_link_offline(ata_dev_phys_link(dev)))
             continue;
 
         /* apply class override */
         if (lflags & ATA_LFLAG_ASSUME_ATA)
             classes[dev->devno] = ATA_DEV_ATA;
         else if (lflags & ATA_LFLAG_ASSUME_SEMB)
             classes[dev->devno] = ATA_DEV_SEMB_UNSUP;
     }
 
     /* record current link speed */
     if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
         link->sata_spd = (sstatus >> 4) & 0xf;
     if (slave && sata_scr_read(slave, SCR_STATUS, &sstatus) == 0)
         slave->sata_spd = (sstatus >> 4) & 0xf;
 
     /* thaw the port */
     if (ata_is_host_link(link))
         ata_eh_thaw_port(ap);
 
     /* postreset() should clear hardware SError.  Although SError
      * is cleared during link resume, clearing SError here is
      * necessary as some PHYs raise hotplug events after SRST.
      * This introduces race condition where hotplug occurs between
      * reset and here.  This race is mediated by cross checking
      * link onlineness and classification result later.
      */
     if (postreset) {
         postreset(link, classes);
         trace_ata_link_postreset(link, classes, rc);
         if (slave) {
             postreset(slave, classes);
             trace_ata_slave_postreset(slave, classes, rc);
         }
     }
 
     /*
      * Some controllers can't be frozen very well and may set spurious
      * error conditions during reset.  Clear accumulated error
      * information and re-thaw the port if frozen.  As reset is the
      * final recovery action and we cross check link onlineness against
      * device classification later, no hotplug event is lost by this.
      */
     spin_lock_irqsave(link->ap->lock, flags);
     memset(&link->eh_info, 0, sizeof(link->eh_info));
     if (slave)
         memset(&slave->eh_info, 0, sizeof(link->eh_info));
     ap->pflags &= ~ATA_PFLAG_EH_PENDING;
     spin_unlock_irqrestore(link->ap->lock, flags);
 
     if (ap->pflags & ATA_PFLAG_FROZEN)
         ata_eh_thaw_port(ap);
 
     /*
      * Make sure onlineness and classification result correspond.
      * Hotplug could have happened during reset and some
      * controllers fail to wait while a drive is spinning up after
      * being hotplugged causing misdetection.  By cross checking
      * link on/offlineness and classification result, those
      * conditions can be reliably detected and retried.
      */
     nr_unknown = 0;
     ata_for_each_dev(dev, link, ALL) {
         if (ata_phys_link_online(ata_dev_phys_link(dev))) {
             if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
                 ata_dev_dbg(dev, "link online but device misclassified\n");
                 classes[dev->devno] = ATA_DEV_NONE;
                 nr_unknown++;
             }
         } else if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
             if (ata_class_enabled(classes[dev->devno]))
                 ata_dev_dbg(dev,
                         "link offline, clearing class %d to NONE\n",
                         classes[dev->devno]);
             classes[dev->devno] = ATA_DEV_NONE;
         } else if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
             ata_dev_dbg(dev,
                     "link status unknown, clearing UNKNOWN to NONE\n");
             classes[dev->devno] = ATA_DEV_NONE;
         }
     }
 
     if (classify && nr_unknown) {
         if (try < max_tries) {
             ata_link_warn(link,
                       "link online but %d devices misclassified, retrying\n",
                       nr_unknown);
             failed_link = link;
             rc = -EAGAIN;
             goto fail;
         }
         ata_link_warn(link,
                   "link online but %d devices misclassified, "
                   "device detection might fail\n", nr_unknown);
     }
 
     /* reset successful, schedule revalidation */
     ata_eh_done(link, NULL, ATA_EH_RESET);
     if (slave)
         ata_eh_done(slave, NULL, ATA_EH_RESET);
     ehc->last_reset = jiffies;      /* update to completion time */
     ehc->i.action |= ATA_EH_REVALIDATE;
     link->lpm_policy = ATA_LPM_UNKNOWN; /* reset LPM state */
 
     rc = 0;
  out:
     /* clear hotplug flag */
     ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
     if (slave)
         sehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
 
     spin_lock_irqsave(ap->lock, flags);
     ap->pflags &= ~ATA_PFLAG_RESETTING;
     spin_unlock_irqrestore(ap->lock, flags);
 
     return rc;
 
  fail:
     /* if SCR isn't accessible on a fan-out port, PMP needs to be reset */
     if (!ata_is_host_link(link) &&
         sata_scr_read(link, SCR_STATUS, &sstatus))
         rc = -ERESTART;
 
     if (try >= max_tries) {
         /*
          * Thaw host port even if reset failed, so that the port
          * can be retried on the next phy event.  This risks
          * repeated EH runs but seems to be a better tradeoff than
          * shutting down a port after a botched hotplug attempt.
          */
         if (ata_is_host_link(link))
             ata_eh_thaw_port(ap);
         goto out;
     }
 
     now = jiffies;
     if (time_before(now, deadline)) {
         unsigned long delta = deadline - now;
 
         ata_link_warn(failed_link,
             "reset failed (errno=%d), retrying in %u secs\n",
             rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));
 
         ata_eh_release(ap);
         while (delta)
             delta = schedule_timeout_uninterruptible(delta);
         ata_eh_acquire(ap);
     }
 
     /*
      * While disks spinup behind PMP, some controllers fail sending SRST.
      * They need to be reset - as well as the PMP - before retrying.
      */
     if (rc == -ERESTART) {
         if (ata_is_host_link(link))
             ata_eh_thaw_port(ap);
         goto out;
     }
 
     if (try == max_tries - 1) {
         sata_down_spd_limit(link, 0);
         if (slave)
             sata_down_spd_limit(slave, 0);
     } else if (rc == -EPIPE)
         sata_down_spd_limit(failed_link, 0);
 
     if (hardreset)
         reset = hardreset;
     goto retry;
 }
 
 static inline void ata_eh_pull_park_action(struct ata_port *ap)
 {
     struct ata_link *link;
     struct ata_device *dev;
     unsigned long flags;
 
     /*
      * This function can be thought of as an extended version of
      * ata_eh_about_to_do() specially crafted to accommodate the
      * requirements of ATA_EH_PARK handling. Since the EH thread
      * does not leave the do {} while () loop in ata_eh_recover as
      * long as the timeout for a park request to *one* device on
      * the port has not expired, and since we still want to pick
      * up park requests to other devices on the same port or
      * timeout updates for the same device, we have to pull
      * ATA_EH_PARK actions from eh_info into eh_context.i
      * ourselves at the beginning of each pass over the loop.
      *
      * Additionally, all write accesses to &ap->park_req_pending
      * through reinit_completion() (see below) or complete_all()
      * (see ata_scsi_park_store()) are protected by the host lock.
      * As a result we have that park_req_pending.done is zero on
      * exit from this function, i.e. when ATA_EH_PARK actions for
      * *all* devices on port ap have been pulled into the
      * respective eh_context structs. If, and only if,
      * park_req_pending.done is non-zero by the time we reach
      * wait_for_completion_timeout(), another ATA_EH_PARK action
      * has been scheduled for at least one of the devices on port
      * ap and we have to cycle over the do {} while () loop in
      * ata_eh_recover() again.
      */
 
     spin_lock_irqsave(ap->lock, flags);
     reinit_completion(&ap->park_req_pending);
     ata_for_each_link(link, ap, EDGE) {
         ata_for_each_dev(dev, link, ALL) {
             struct ata_eh_info *ehi = &link->eh_info;
 
             link->eh_context.i.dev_action[dev->devno] |=
                 ehi->dev_action[dev->devno] & ATA_EH_PARK;
             ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
         }
     }
     spin_unlock_irqrestore(ap->lock, flags);
 }
 
 static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
 {
     struct ata_eh_context *ehc = &dev->link->eh_context;
     struct ata_taskfile tf;
     unsigned int err_mask;
 
     ata_tf_init(dev, &tf);
     if (park) {
         ehc->unloaded_mask |= 1 << dev->devno;
         tf.command = ATA_CMD_IDLEIMMEDIATE;
         tf.feature = 0x44;
         tf.lbal = 0x4c;
         tf.lbam = 0x4e;
         tf.lbah = 0x55;
     } else {
         ehc->unloaded_mask &= ~(1 << dev->devno);
         tf.command = ATA_CMD_CHK_POWER;
     }
 
     tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
     tf.protocol = ATA_PROT_NODATA;
     err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
     if (park && (err_mask || tf.lbal != 0xc4)) {
         ata_dev_err(dev, "head unload failed!\n");
         ehc->unloaded_mask &= ~(1 << dev->devno);
     }
 }
 
 static int ata_eh_revalidate_and_attach(struct ata_link *link,
                     struct ata_device **r_failed_dev)
 {
     struct ata_port *ap = link->ap;
     struct ata_eh_context *ehc = &link->eh_context;
     struct ata_device *dev;
     unsigned int new_mask = 0;
     unsigned long flags;
     int rc = 0;
 
     /* For PATA drive side cable detection to work, IDENTIFY must
      * be done backwards such that PDIAG- is released by the slave
      * device before the master device is identified.
      */
     ata_for_each_dev(dev, link, ALL_REVERSE) {
         unsigned int action = ata_eh_dev_action(dev);
         unsigned int readid_flags = 0;
 
         if (ehc->i.flags & ATA_EHI_DID_RESET)
             readid_flags |= ATA_READID_POSTRESET;
 
         if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
             WARN_ON(dev->class == ATA_DEV_PMP);
 
             if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
                 rc = -EIO;
                 goto err;
             }
 
             ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
             rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
                         readid_flags);
             if (rc)
                 goto err;
 
             ata_eh_done(link, dev, ATA_EH_REVALIDATE);
 
             /* Configuration may have changed, reconfigure
              * transfer mode.
              */
             ehc->i.flags |= ATA_EHI_SETMODE;
 
             /* schedule the scsi_rescan_device() here */
             schedule_work(&(ap->scsi_rescan_task));
         } else if (dev->class == ATA_DEV_UNKNOWN &&
                ehc->tries[dev->devno] &&
                ata_class_enabled(ehc->classes[dev->devno])) {
             /* Temporarily set dev->class, it will be
              * permanently set once all configurations are
              * complete.  This is necessary because new
              * device configuration is done in two
              * separate loops.
              */
             dev->class = ehc->classes[dev->devno];
 
             if (dev->class == ATA_DEV_PMP)
                 rc = sata_pmp_attach(dev);
             else
                 rc = ata_dev_read_id(dev, &dev->class,
                              readid_flags, dev->id);
 
             /* read_id might have changed class, store and reset */
             ehc->classes[dev->devno] = dev->class;
             dev->class = ATA_DEV_UNKNOWN;
 
             switch (rc) {
             case 0:
                 /* clear error info accumulated during probe */
                 ata_ering_clear(&dev->ering);
                 new_mask |= 1 << dev->devno;
                 break;
             case -ENOENT:
                 /* IDENTIFY was issued to non-existent
                  * device.  No need to reset.  Just
                  * thaw and ignore the device.
                  */
                 ata_eh_thaw_port(ap);
                 break;
             default:
                 goto err;
             }
         }
     }
 
     /* PDIAG- should have been released, ask cable type if post-reset */
     if ((ehc->i.flags & ATA_EHI_DID_RESET) && ata_is_host_link(link)) {
         if (ap->ops->cable_detect)
             ap->cbl = ap->ops->cable_detect(ap);
         ata_force_cbl(ap);
     }
 
     /* Configure new devices forward such that user doesn't see
      * device detection messages backwards.
      */
     ata_for_each_dev(dev, link, ALL) {
         if (!(new_mask & (1 << dev->devno)))
             continue;
 
         dev->class = ehc->classes[dev->devno];
 
         if (dev->class == ATA_DEV_PMP)
             continue;
 
         ehc->i.flags |= ATA_EHI_PRINTINFO;
         rc = ata_dev_configure(dev);
         ehc->i.flags &= ~ATA_EHI_PRINTINFO;
         if (rc) {
             dev->class = ATA_DEV_UNKNOWN;
             goto err;
         }
 
         spin_lock_irqsave(ap->lock, flags);
         ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
         spin_unlock_irqrestore(ap->lock, flags);
 
         /* new device discovered, configure xfermode */
         ehc->i.flags |= ATA_EHI_SETMODE;
     }
 
     return 0;
 
  err:
     *r_failed_dev = dev;
     return rc;
 }
 
 /**
  *  ata_set_mode - Program timings and issue SET FEATURES - XFER
  *  @link: link on which timings will be programmed
  *  @r_failed_dev: out parameter for failed device
  *
  *  Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
  *  ata_set_mode() fails, pointer to the failing device is
  *  returned in @r_failed_dev.
  *
  *  LOCKING:
  *  PCI/etc. bus probe sem.
  *
  *  RETURNS:
  *  0 on success, negative errno otherwise
  */
 int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
 {
     struct ata_port *ap = link->ap;
     struct ata_device *dev;
     int rc;
 
     /* if data transfer is verified, clear DUBIOUS_XFER on ering top */
     ata_for_each_dev(dev, link, ENABLED) {
         if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
             struct ata_ering_entry *ent;
 
             ent = ata_ering_top(&dev->ering);
             if (ent)
                 ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
         }
     }
 
     /* has private set_mode? */
     if (ap->ops->set_mode)
         rc = ap->ops->set_mode(link, r_failed_dev);
     else
         rc = ata_do_set_mode(link, r_failed_dev);
 
     /* if transfer mode has changed, set DUBIOUS_XFER on device */
     ata_for_each_dev(dev, link, ENABLED) {
         struct ata_eh_context *ehc = &link->eh_context;
         u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
         u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));
 
         if (dev->xfer_mode != saved_xfer_mode ||
             ata_ncq_enabled(dev) != saved_ncq)
             dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
     }
 
     return rc;
 }
 
 /**
  *  atapi_eh_clear_ua - Clear ATAPI UNIT ATTENTION after reset
  *  @dev: ATAPI device to clear UA for
  *
  *  Resets and other operations can make an ATAPI device raise
  *  UNIT ATTENTION which causes the next operation to fail.  This
  *  function clears UA.
  *
  *  LOCKING:
  *  EH context (may sleep).
  *
  *  RETURNS:
  *  0 on success, -errno on failure.
  */
 static int atapi_eh_clear_ua(struct ata_device *dev)
 {
     int i;
 
     for (i = 0; i < ATA_EH_UA_TRIES; i++) {
         u8 *sense_buffer = dev->link->ap->sector_buf;
         u8 sense_key = 0;
         unsigned int err_mask;
 
         err_mask = atapi_eh_tur(dev, &sense_key);
         if (err_mask != 0 && err_mask != AC_ERR_DEV) {
             ata_dev_warn(dev,
                      "TEST_UNIT_READY failed (err_mask=0x%x)\n",
                      err_mask);
             return -EIO;
         }
 
         if (!err_mask || sense_key != UNIT_ATTENTION)
             return 0;
 
         err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
         if (err_mask) {
             ata_dev_warn(dev, "failed to clear "
                 "UNIT ATTENTION (err_mask=0x%x)\n", err_mask);
             return -EIO;
         }
     }
 
     ata_dev_warn(dev, "UNIT ATTENTION persists after %d tries\n",
              ATA_EH_UA_TRIES);
 
     return 0;
 }
 
 /**
  *  ata_eh_maybe_retry_flush - Retry FLUSH if necessary
  *  @dev: ATA device which may need FLUSH retry
  *
  *  If @dev failed FLUSH, it needs to be reported upper layer
  *  immediately as it means that @dev failed to remap and already
  *  lost at least a sector and further FLUSH retrials won't make
  *  any difference to the lost sector.  However, if FLUSH failed
  *  for other reasons, for example transmission error, FLUSH needs
  *  to be retried.
  *
  *  This function determines whether FLUSH failure retry is
  *  necessary and performs it if so.
  *
  *  RETURNS:
  *  0 if EH can continue, -errno if EH needs to be repeated.
  */
 static int ata_eh_maybe_retry_flush(struct ata_device *dev)
 {
     struct ata_link *link = dev->link;
     struct ata_port *ap = link->ap;
     struct ata_queued_cmd *qc;
     struct ata_taskfile tf;
     unsigned int err_mask;
     int rc = 0;
 
     /* did flush fail for this device? */
     if (!ata_tag_valid(link->active_tag))
         return 0;
 
     qc = __ata_qc_from_tag(ap, link->active_tag);
     if (qc->dev != dev || (qc->tf.command != ATA_CMD_FLUSH_EXT &&
                    qc->tf.command != ATA_CMD_FLUSH))
         return 0;
 
     /* if the device failed it, it should be reported to upper layers */
     if (qc->err_mask & AC_ERR_DEV)
         return 0;
 
     /* flush failed for some other reason, give it another shot */
     ata_tf_init(dev, &tf);
 
     tf.command = qc->tf.command;
     tf.flags |= ATA_TFLAG_DEVICE;
     tf.protocol = ATA_PROT_NODATA;
 
     ata_dev_warn(dev, "retrying FLUSH 0x%x Emask 0x%x\n",
                tf.command, qc->err_mask);
 
     err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
     if (!err_mask) {
         /*
          * FLUSH is complete but there's no way to
          * successfully complete a failed command from EH.
          * Making sure retry is allowed at least once and
          * retrying it should do the trick - whatever was in
          * the cache is already on the platter and this won't
          * cause infinite loop.
          */
         qc->scsicmd->allowed = max(qc->scsicmd->allowed, 1);
     } else {
         ata_dev_warn(dev, "FLUSH failed Emask 0x%x\n",
                    err_mask);
         rc = -EIO;
 
         /* if device failed it, report it to upper layers */
         if (err_mask & AC_ERR_DEV) {
             qc->err_mask |= AC_ERR_DEV;
             qc->result_tf = tf;
             if (!(ap->pflags & ATA_PFLAG_FROZEN))
                 rc = 0;
         }
     }
     return rc;
 }
 
 /**
  *  ata_eh_set_lpm - configure SATA interface power management
  *  @link: link to configure power management
  *  @policy: the link power management policy
  *  @r_failed_dev: out parameter for failed device
  *
  *  Enable SATA Interface power management.  This will enable
  *  Device Interface Power Management (DIPM) for min_power and
  *  medium_power_with_dipm policies, and then call driver specific
  *  callbacks for enabling Host Initiated Power management.
  *
  *  LOCKING:
  *  EH context.
  *
  *  RETURNS:
  *  0 on success, -errno on failure.
  */
 static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
               struct ata_device **r_failed_dev)
 {
     struct ata_port *ap = ata_is_host_link(link) ? link->ap : NULL;
     struct ata_eh_context *ehc = &link->eh_context;
     struct ata_device *dev, *link_dev = NULL, *lpm_dev = NULL;
     enum ata_lpm_policy old_policy = link->lpm_policy;
     bool no_dipm = link->ap->flags & ATA_FLAG_NO_DIPM;
     unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM;
     unsigned int err_mask;
     int rc;
 
     /* if the link or host doesn't do LPM, noop */
     if (!IS_ENABLED(CONFIG_SATA_HOST) ||
         (link->flags & ATA_LFLAG_NO_LPM) || (ap && !ap->ops->set_lpm))
         return 0;
 
     /*
      * DIPM is enabled only for MIN_POWER as some devices
      * misbehave when the host NACKs transition to SLUMBER.  Order
      * device and link configurations such that the host always
      * allows DIPM requests.
      */
     ata_for_each_dev(dev, link, ENABLED) {
         bool hipm = ata_id_has_hipm(dev->id);
         bool dipm = ata_id_has_dipm(dev->id) && !no_dipm;
 
         /* find the first enabled and LPM enabled devices */
         if (!link_dev)
             link_dev = dev;
 
         if (!lpm_dev && (hipm || dipm))
             lpm_dev = dev;
 
         hints &= ~ATA_LPM_EMPTY;
         if (!hipm)
             hints &= ~ATA_LPM_HIPM;
 
         /* disable DIPM before changing link config */
         if (policy < ATA_LPM_MED_POWER_WITH_DIPM && dipm) {
             err_mask = ata_dev_set_feature(dev,
                     SETFEATURES_SATA_DISABLE, SATA_DIPM);
             if (err_mask && err_mask != AC_ERR_DEV) {
                 ata_dev_warn(dev,
                          "failed to disable DIPM, Emask 0x%x\n",
                          err_mask);
                 rc = -EIO;
                 goto fail;
             }
         }
     }
 
     if (ap) {
         rc = ap->ops->set_lpm(link, policy, hints);
         if (!rc && ap->slave_link)
             rc = ap->ops->set_lpm(ap->slave_link, policy, hints);
     } else
         rc = sata_pmp_set_lpm(link, policy, hints);
 
     /*
      * Attribute link config failure to the first (LPM) enabled
      * device on the link.
      */
     if (rc) {
         if (rc == -EOPNOTSUPP) {
             link->flags |= ATA_LFLAG_NO_LPM;
             return 0;
         }
         dev = lpm_dev ? lpm_dev : link_dev;
         goto fail;
     }
 
     /*
      * Low level driver acked the transition.  Issue DIPM command
      * with the new policy set.
      */
     link->lpm_policy = policy;
     if (ap && ap->slave_link)
         ap->slave_link->lpm_policy = policy;
 
     /* host config updated, enable DIPM if transitioning to MIN_POWER */
     ata_for_each_dev(dev, link, ENABLED) {
         if (policy >= ATA_LPM_MED_POWER_WITH_DIPM && !no_dipm &&
             ata_id_has_dipm(dev->id)) {
             err_mask = ata_dev_set_feature(dev,
                     SETFEATURES_SATA_ENABLE, SATA_DIPM);
             if (err_mask && err_mask != AC_ERR_DEV) {
                 ata_dev_warn(dev,
                     "failed to enable DIPM, Emask 0x%x\n",
                     err_mask);
                 rc = -EIO;
                 goto fail;
             }
         }
     }
 
     link->last_lpm_change = jiffies;
     link->flags |= ATA_LFLAG_CHANGED;
 
     return 0;
 
 fail:
     /* restore the old policy */
     link->lpm_policy = old_policy;
     if (ap && ap->slave_link)
         ap->slave_link->lpm_policy = old_policy;
 
     /* if no device or only one more chance is left, disable LPM */
     if (!dev || ehc->tries[dev->devno] <= 2) {
         ata_link_warn(link, "disabling LPM on the link\n");
         link->flags |= ATA_LFLAG_NO_LPM;
     }
     if (r_failed_dev)
         *r_failed_dev = dev;
     return rc;
 }
 
 int ata_link_nr_enabled(struct ata_link *link)
 {
     struct ata_device *dev;
     int cnt = 0;
 
     ata_for_each_dev(dev, link, ENABLED)
         cnt++;
     return cnt;
 }
 
 static int ata_link_nr_vacant(struct ata_link *link)
 {
     struct ata_device *dev;
     int cnt = 0;
 
     ata_for_each_dev(dev, link, ALL)
         if (dev->class == ATA_DEV_UNKNOWN)
             cnt++;
     return cnt;
 }
 
 static int ata_eh_skip_recovery(struct ata_link *link)
 {
     struct ata_port *ap = link->ap;
     struct ata_eh_context *ehc = &link->eh_context;
     struct ata_device *dev;
 
     /* skip disabled links */
     if (link->flags & ATA_LFLAG_DISABLED)
         return 1;
 
     /* skip if explicitly requested */
     if (ehc->i.flags & ATA_EHI_NO_RECOVERY)
         return 1;
 
     /* thaw frozen port and recover failed devices */
     if ((ap->pflags & ATA_PFLAG_FROZEN) || ata_link_nr_enabled(link))
         return 0;
 
     /* reset at least once if reset is requested */
     if ((ehc->i.action & ATA_EH_RESET) &&
         !(ehc->i.flags & ATA_EHI_DID_RESET))
         return 0;
 
     /* skip if class codes for all vacant slots are ATA_DEV_NONE */
     ata_for_each_dev(dev, link, ALL) {
         if (dev->class == ATA_DEV_UNKNOWN &&
             ehc->classes[dev->devno] != ATA_DEV_NONE)
             return 0;
     }
 
     return 1;
 }
 
 static int ata_count_probe_trials_cb(struct ata_ering_entry *ent, void *void_arg)
 {
     u64 interval = msecs_to_jiffies(ATA_EH_PROBE_TRIAL_INTERVAL);
     u64 now = get_jiffies_64();
     int *trials = void_arg;
 
     if ((ent->eflags & ATA_EFLAG_OLD_ER) ||
         (ent->timestamp < now - min(now, interval)))
         return -1;
 
     (*trials)++;
     return 0;
 }
 
 static int ata_eh_schedule_probe(struct ata_device *dev)
 {
     struct ata_eh_context *ehc = &dev->link->eh_context;
     struct ata_link *link = ata_dev_phys_link(dev);
     int trials = 0;
 
     if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
         (ehc->did_probe_mask & (1 << dev->devno)))
         return 0;
 
     ata_eh_detach_dev(dev);
     ata_dev_init(dev);
     ehc->did_probe_mask |= (1 << dev->devno);
     ehc->i.action |= ATA_EH_RESET;
     ehc->saved_xfer_mode[dev->devno] = 0;
     ehc->saved_ncq_enabled &= ~(1 << dev->devno);
 
     /* the link maybe in a deep sleep, wake it up */
     if (link->lpm_policy > ATA_LPM_MAX_POWER) {
         if (ata_is_host_link(link))
             link->ap->ops->set_lpm(link, ATA_LPM_MAX_POWER,
                            ATA_LPM_EMPTY);
         else
             sata_pmp_set_lpm(link, ATA_LPM_MAX_POWER,
                      ATA_LPM_EMPTY);
     }
 
     /* Record and count probe trials on the ering.  The specific
      * error mask used is irrelevant.  Because a successful device
      * detection clears the ering, this count accumulates only if
      * there are consecutive failed probes.
      *
      * If the count is equal to or higher than ATA_EH_PROBE_TRIALS
      * in the last ATA_EH_PROBE_TRIAL_INTERVAL, link speed is
      * forced to 1.5Gbps.
      *
      * This is to work around cases where failed link speed
      * negotiation results in device misdetection leading to
      * infinite DEVXCHG or PHRDY CHG events.
      */
     ata_ering_record(&dev->ering, 0, AC_ERR_OTHER);
     ata_ering_map(&dev->ering, ata_count_probe_trials_cb, &trials);
 
     if (trials > ATA_EH_PROBE_TRIALS)
         sata_down_spd_limit(link, 1);
 
     return 1;
 }
 
 static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
 {
     struct ata_eh_context *ehc = &dev->link->eh_context;
 
     /* -EAGAIN from EH routine indicates retry without prejudice.
      * The requester is responsible for ensuring forward progress.
      */
     if (err != -EAGAIN)
         ehc->tries[dev->devno]--;
 
     switch (err) {
     case -ENODEV:
         /* device missing or wrong IDENTIFY data, schedule probing */
         ehc->i.probe_mask |= (1 << dev->devno);
         fallthrough;
     case -EINVAL:
         /* give it just one more chance */
         ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
         fallthrough;
     case -EIO:
         if (ehc->tries[dev->devno] == 1) {
             /* This is the last chance, better to slow
              * down than lose it.
              */
             sata_down_spd_limit(ata_dev_phys_link(dev), 0);
             if (dev->pio_mode > XFER_PIO_0)
                 ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
         }
     }
 
     if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
         /* disable device if it has used up all its chances */
         ata_dev_disable(dev);
 
         /* detach if offline */
         if (ata_phys_link_offline(ata_dev_phys_link(dev)))
             ata_eh_detach_dev(dev);
 
         /* schedule probe if necessary */
         if (ata_eh_schedule_probe(dev)) {
             ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
             memset(ehc->cmd_timeout_idx[dev->devno], 0,
                    sizeof(ehc->cmd_timeout_idx[dev->devno]));
         }
 
         return 1;
     } else {
         ehc->i.action |= ATA_EH_RESET;
         return 0;
     }
 }
 
 /**
  *  ata_eh_recover - recover host port after error
  *  @ap: host port to recover
  *  @prereset: prereset method (can be NULL)
  *  @softreset: softreset method (can be NULL)
  *  @hardreset: hardreset method (can be NULL)
  *  @postreset: postreset method (can be NULL)
  *  @r_failed_link: out parameter for failed link
  *
  *  This is the alpha and omega, eum and yang, heart and soul of
  *  libata exception handling.  On entry, actions required to
  *  recover each link and hotplug requests are recorded in the
  *  link's eh_context.  This function executes all the operations
  *  with appropriate retrials and fallbacks to resurrect failed
  *  devices, detach goners and greet newcomers.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  *
  *  RETURNS:
  *  0 on success, -errno on failure.
  */
 int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
            ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
            ata_postreset_fn_t postreset,
            struct ata_link **r_failed_link)
 {
     struct ata_link *link;
     struct ata_device *dev;
     int rc, nr_fails;
     unsigned long flags, deadline;
 
     /* prep for recovery */
     ata_for_each_link(link, ap, EDGE) {
         struct ata_eh_context *ehc = &link->eh_context;
 
         /* re-enable link? */
         if (ehc->i.action & ATA_EH_ENABLE_LINK) {
             ata_eh_about_to_do(link, NULL, ATA_EH_ENABLE_LINK);
             spin_lock_irqsave(ap->lock, flags);
             link->flags &= ~ATA_LFLAG_DISABLED;
             spin_unlock_irqrestore(ap->lock, flags);
             ata_eh_done(link, NULL, ATA_EH_ENABLE_LINK);
         }
 
         ata_for_each_dev(dev, link, ALL) {
             if (link->flags & ATA_LFLAG_NO_RETRY)
                 ehc->tries[dev->devno] = 1;
             else
                 ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
 
             /* collect port action mask recorded in dev actions */
             ehc->i.action |= ehc->i.dev_action[dev->devno] &
                      ~ATA_EH_PERDEV_MASK;
             ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
 
             /* process hotplug request */
             if (dev->flags & ATA_DFLAG_DETACH)
                 ata_eh_detach_dev(dev);
 
             /* schedule probe if necessary */
             if (!ata_dev_enabled(dev))
                 ata_eh_schedule_probe(dev);
         }
     }
 
  retry:
     rc = 0;
 
     /* if UNLOADING, finish immediately */
     if (ap->pflags & ATA_PFLAG_UNLOADING)
         goto out;
 
     /* prep for EH */
     ata_for_each_link(link, ap, EDGE) {
         struct ata_eh_context *ehc = &link->eh_context;
 
         /* skip EH if possible. */
         if (ata_eh_skip_recovery(link))
             ehc->i.action = 0;
 
         ata_for_each_dev(dev, link, ALL)
             ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
     }
 
     /* reset */
     ata_for_each_link(link, ap, EDGE) {
         struct ata_eh_context *ehc = &link->eh_context;
 
         if (!(ehc->i.action & ATA_EH_RESET))
             continue;
 
         rc = ata_eh_reset(link, ata_link_nr_vacant(link),
                   prereset, softreset, hardreset, postreset);
         if (rc) {
             ata_link_err(link, "reset failed, giving up\n");
             goto out;
         }
     }
 
     do {
         unsigned long now;
 
         /*
          * clears ATA_EH_PARK in eh_info and resets
          * ap->park_req_pending
          */
         ata_eh_pull_park_action(ap);
 
         deadline = jiffies;
         ata_for_each_link(link, ap, EDGE) {
             ata_for_each_dev(dev, link, ALL) {
                 struct ata_eh_context *ehc = &link->eh_context;
                 unsigned long tmp;
 
                 if (dev->class != ATA_DEV_ATA &&
                     dev->class != ATA_DEV_ZAC)
                     continue;
                 if (!(ehc->i.dev_action[dev->devno] &
                       ATA_EH_PARK))
                     continue;
                 tmp = dev->unpark_deadline;
                 if (time_before(deadline, tmp))
                     deadline = tmp;
                 else if (time_before_eq(tmp, jiffies))
                     continue;
                 if (ehc->unloaded_mask & (1 << dev->devno))
                     continue;
 
                 ata_eh_park_issue_cmd(dev, 1);
             }
         }
 
         now = jiffies;
         if (time_before_eq(deadline, now))
             break;
 
         ata_eh_release(ap);
         deadline = wait_for_completion_timeout(&ap->park_req_pending,
                                deadline - now);
         ata_eh_acquire(ap);
     } while (deadline);
     ata_for_each_link(link, ap, EDGE) {
         ata_for_each_dev(dev, link, ALL) {
             if (!(link->eh_context.unloaded_mask &
                   (1 << dev->devno)))
                 continue;
 
             ata_eh_park_issue_cmd(dev, 0);
             ata_eh_done(link, dev, ATA_EH_PARK);
         }
     }
 
     /* the rest */
     nr_fails = 0;
     ata_for_each_link(link, ap, PMP_FIRST) {
         struct ata_eh_context *ehc = &link->eh_context;
 
         if (sata_pmp_attached(ap) && ata_is_host_link(link))
             goto config_lpm;
 
         /* revalidate existing devices and attach new ones */
         rc = ata_eh_revalidate_and_attach(link, &dev);
         if (rc)
             goto rest_fail;
 
         /* if PMP got attached, return, pmp EH will take care of it */
         if (link->device->class == ATA_DEV_PMP) {
             ehc->i.action = 0;
             return 0;
         }
 
         /* configure transfer mode if necessary */
         if (ehc->i.flags & ATA_EHI_SETMODE) {
             rc = ata_set_mode(link, &dev);
             if (rc)
                 goto rest_fail;
             ehc->i.flags &= ~ATA_EHI_SETMODE;
         }
 
         /* If reset has been issued, clear UA to avoid
          * disrupting the current users of the device.
          */
         if (ehc->i.flags & ATA_EHI_DID_RESET) {
             ata_for_each_dev(dev, link, ALL) {
                 if (dev->class != ATA_DEV_ATAPI)
                     continue;
                 rc = atapi_eh_clear_ua(dev);
                 if (rc)
                     goto rest_fail;
                 if (zpodd_dev_enabled(dev))
                     zpodd_post_poweron(dev);
             }
         }
 
         /* retry flush if necessary */
         ata_for_each_dev(dev, link, ALL) {
             if (dev->class != ATA_DEV_ATA &&
                 dev->class != ATA_DEV_ZAC)
                 continue;
             rc = ata_eh_maybe_retry_flush(dev);
             if (rc)
                 goto rest_fail;
         }
 
     config_lpm:
         /* configure link power saving */
         if (link->lpm_policy != ap->target_lpm_policy) {
             rc = ata_eh_set_lpm(link, ap->target_lpm_policy, &dev);
             if (rc)
                 goto rest_fail;
         }
 
         /* this link is okay now */
         ehc->i.flags = 0;
         continue;
 
     rest_fail:
         nr_fails++;
         if (dev)
             ata_eh_handle_dev_fail(dev, rc);
 
         if (ap->pflags & ATA_PFLAG_FROZEN) {
             /* PMP reset requires working host port.
              * Can't retry if it's frozen.
              */
             if (sata_pmp_attached(ap))
                 goto out;
             break;
         }
     }
 
     if (nr_fails)
         goto retry;
 
  out:
     if (rc && r_failed_link)
         *r_failed_link = link;
 
     return rc;
 }
 
 /**
  *  ata_eh_finish - finish up EH
  *  @ap: host port to finish EH for
  *
  *  Recovery is complete.  Clean up EH states and retry or finish
  *  failed qcs.
  *
  *  LOCKING:
  *  None.
  */
 void ata_eh_finish(struct ata_port *ap)
 {
     struct ata_queued_cmd *qc;
     int tag;
 
     /* retry or finish qcs */
     ata_qc_for_each_raw(ap, qc, tag) {
         if (!(qc->flags & ATA_QCFLAG_FAILED))
             continue;
 
         if (qc->err_mask) {
             /* FIXME: Once EH migration is complete,
              * generate sense data in this function,
              * considering both err_mask and tf.
              */
             if (qc->flags & ATA_QCFLAG_RETRY)
                 ata_eh_qc_retry(qc);
             else
                 ata_eh_qc_complete(qc);
         } else {
             if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
                 ata_eh_qc_complete(qc);
             } else {
                 /* feed zero TF to sense generation */
                 memset(&qc->result_tf, 0, sizeof(qc->result_tf));
                 ata_eh_qc_retry(qc);
             }
         }
     }
 
     /* make sure nr_active_links is zero after EH */
     WARN_ON(ap->nr_active_links);
     ap->nr_active_links = 0;
 }
 
 /**
  *  ata_do_eh - do standard error handling
  *  @ap: host port to handle error for
  *
  *  @prereset: prereset method (can be NULL)
  *  @softreset: softreset method (can be NULL)
  *  @hardreset: hardreset method (can be NULL)
  *  @postreset: postreset method (can be NULL)
  *
  *  Perform standard error handling sequence.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
            ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
            ata_postreset_fn_t postreset)
 {
     struct ata_device *dev;
     int rc;
 
     ata_eh_autopsy(ap);
     ata_eh_report(ap);
 
     rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
                 NULL);
     if (rc) {
         ata_for_each_dev(dev, &ap->link, ALL)
             ata_dev_disable(dev);
     }
 
     ata_eh_finish(ap);
 }
 
 /**
  *  ata_std_error_handler - standard error handler
  *  @ap: host port to handle error for
  *
  *  Standard error handler
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 void ata_std_error_handler(struct ata_port *ap)
 {
     struct ata_port_operations *ops = ap->ops;
     ata_reset_fn_t hardreset = ops->hardreset;
 
     /* ignore built-in hardreset if SCR access is not available */
     if (hardreset == sata_std_hardreset && !sata_scr_valid(&ap->link))
         hardreset = NULL;
 
     ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
 }
 EXPORT_SYMBOL_GPL(ata_std_error_handler);
 
 #ifdef CONFIG_PM
 /**
  *  ata_eh_handle_port_suspend - perform port suspend operation
  *  @ap: port to suspend
  *
  *  Suspend @ap.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 static void ata_eh_handle_port_suspend(struct ata_port *ap)
 {
     unsigned long flags;
     int rc = 0;
     struct ata_device *dev;
 
     /* are we suspending? */
     spin_lock_irqsave(ap->lock, flags);
     if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
         ap->pm_mesg.event & PM_EVENT_RESUME) {
         spin_unlock_irqrestore(ap->lock, flags);
         return;
     }
     spin_unlock_irqrestore(ap->lock, flags);
 
     WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED);
 
     /*
      * If we have a ZPODD attached, check its zero
      * power ready status before the port is frozen.
      * Only needed for runtime suspend.
      */
     if (PMSG_IS_AUTO(ap->pm_mesg)) {
         ata_for_each_dev(dev, &ap->link, ENABLED) {
             if (zpodd_dev_enabled(dev))
                 zpodd_on_suspend(dev);
         }
     }
 
     /* suspend */
     ata_eh_freeze_port(ap);
 
     if (ap->ops->port_suspend)
         rc = ap->ops->port_suspend(ap, ap->pm_mesg);
 
     ata_acpi_set_state(ap, ap->pm_mesg);
 
     /* update the flags */
     spin_lock_irqsave(ap->lock, flags);
 
     ap->pflags &= ~ATA_PFLAG_PM_PENDING;
     if (rc == 0)
         ap->pflags |= ATA_PFLAG_SUSPENDED;
     else if (ap->pflags & ATA_PFLAG_FROZEN)
         ata_port_schedule_eh(ap);
 
     spin_unlock_irqrestore(ap->lock, flags);
 
     return;
 }
 
 /**
  *  ata_eh_handle_port_resume - perform port resume operation
  *  @ap: port to resume
  *
  *  Resume @ap.
  *
  *  LOCKING:
  *  Kernel thread context (may sleep).
  */
 static void ata_eh_handle_port_resume(struct ata_port *ap)
 {
     struct ata_link *link;
     struct ata_device *dev;
     unsigned long flags;
 
     /* are we resuming? */
     spin_lock_irqsave(ap->lock, flags);
     if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
         !(ap->pm_mesg.event & PM_EVENT_RESUME)) {
         spin_unlock_irqrestore(ap->lock, flags);
         return;
     }
     spin_unlock_irqrestore(ap->lock, flags);
 
     WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
 
     /*
      * Error timestamps are in jiffies which doesn't run while
      * suspended and PHY events during resume isn't too uncommon.
      * When the two are combined, it can lead to unnecessary speed
      * downs if the machine is suspended and resumed repeatedly.
      * Clear error history.
      */
     ata_for_each_link(link, ap, HOST_FIRST)
         ata_for_each_dev(dev, link, ALL)
             ata_ering_clear(&dev->ering);
 
     ata_acpi_set_state(ap, ap->pm_mesg);
 
     if (ap->ops->port_resume)
         ap->ops->port_resume(ap);
 
     /* tell ACPI that we're resuming */
     ata_acpi_on_resume(ap);
 
     /* update the flags */
     spin_lock_irqsave(ap->lock, flags);
     ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
     spin_unlock_irqrestore(ap->lock, flags);
 }
 #endif /* CONFIG_PM */