OSCL-LXR linux-6.0.1/​include/​scsi/​scsi_host.h	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _SCSI_SCSI_HOST_H
 #define _SCSI_SCSI_HOST_H
 
 #include <linux/device.h>
 #include <linux/list.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
 #include <linux/seq_file.h>
 #include <linux/blk-mq.h>
 #include <scsi/scsi.h>
 
 struct block_device;
 struct completion;
 struct module;
 struct scsi_cmnd;
 struct scsi_device;
 struct scsi_target;
 struct Scsi_Host;
 struct scsi_transport_template;
 
 
 #define SG_ALL  SG_CHUNK_SIZE
 
 #define MODE_UNKNOWN 0x00
 #define MODE_INITIATOR 0x01
 #define MODE_TARGET 0x02
 
 struct scsi_host_template {
     /*
      * Put fields referenced in IO submission path together in
      * same cacheline
      */
 
     /*
      * Additional per-command data allocated for the driver.
      */
     unsigned int cmd_size;
 
     /*
      * The queuecommand function is used to queue up a scsi
      * command block to the LLDD.  When the driver finished
      * processing the command the done callback is invoked.
      *
      * If queuecommand returns 0, then the driver has accepted the
      * command.  It must also push it to the HBA if the scsi_cmnd
      * flag SCMD_LAST is set, or if the driver does not implement
      * commit_rqs.  The done() function must be called on the command
      * when the driver has finished with it. (you may call done on the
      * command before queuecommand returns, but in this case you
      * *must* return 0 from queuecommand).
      *
      * Queuecommand may also reject the command, in which case it may
      * not touch the command and must not call done() for it.
      *
      * There are two possible rejection returns:
      *
      *   SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
      *   allow commands to other devices serviced by this host.
      *
      *   SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
      *   host temporarily.
      *
          * For compatibility, any other non-zero return is treated the
          * same as SCSI_MLQUEUE_HOST_BUSY.
      *
      * NOTE: "temporarily" means either until the next command for#
      * this device/host completes, or a period of time determined by
      * I/O pressure in the system if there are no other outstanding
      * commands.
      *
      * STATUS: REQUIRED
      */
     int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
 
     /*
      * The commit_rqs function is used to trigger a hardware
      * doorbell after some requests have been queued with
      * queuecommand, when an error is encountered before sending
      * the request with SCMD_LAST set.
      *
      * STATUS: OPTIONAL
      */
     void (*commit_rqs)(struct Scsi_Host *, u16);
 
     struct module *module;
     const char *name;
 
     /*
      * The info function will return whatever useful information the
      * developer sees fit.  If not provided, then the name field will
      * be used instead.
      *
      * Status: OPTIONAL
      */
     const char *(*info)(struct Scsi_Host *);
 
     /*
      * Ioctl interface
      *
      * Status: OPTIONAL
      */
     int (*ioctl)(struct scsi_device *dev, unsigned int cmd,
              void __user *arg);
 
 
 #ifdef CONFIG_COMPAT
     /*
      * Compat handler. Handle 32bit ABI.
      * When unknown ioctl is passed return -ENOIOCTLCMD.
      *
      * Status: OPTIONAL
      */
     int (*compat_ioctl)(struct scsi_device *dev, unsigned int cmd,
                 void __user *arg);
 #endif
 
     int (*init_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
     int (*exit_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
 
     /*
      * This is an error handling strategy routine.  You don't need to
      * define one of these if you don't want to - there is a default
      * routine that is present that should work in most cases.  For those
      * driver authors that have the inclination and ability to write their
      * own strategy routine, this is where it is specified.  Note - the
      * strategy routine is *ALWAYS* run in the context of the kernel eh
      * thread.  Thus you are guaranteed to *NOT* be in an interrupt
      * handler when you execute this, and you are also guaranteed to
      * *NOT* have any other commands being queued while you are in the
      * strategy routine. When you return from this function, operations
      * return to normal.
      *
      * See scsi_error.c scsi_unjam_host for additional comments about
      * what this function should and should not be attempting to do.
      *
      * Status: REQUIRED (at least one of them)
      */
     int (* eh_abort_handler)(struct scsi_cmnd *);
     int (* eh_device_reset_handler)(struct scsi_cmnd *);
     int (* eh_target_reset_handler)(struct scsi_cmnd *);
     int (* eh_bus_reset_handler)(struct scsi_cmnd *);
     int (* eh_host_reset_handler)(struct scsi_cmnd *);
 
     /*
      * Before the mid layer attempts to scan for a new device where none
      * currently exists, it will call this entry in your driver.  Should
      * your driver need to allocate any structs or perform any other init
      * items in order to send commands to a currently unused target/lun
      * combo, then this is where you can perform those allocations.  This
      * is specifically so that drivers won't have to perform any kind of
      * "is this a new device" checks in their queuecommand routine,
      * thereby making the hot path a bit quicker.
      *
      * Return values: 0 on success, non-0 on failure
      *
      * Deallocation:  If we didn't find any devices at this ID, you will
      * get an immediate call to slave_destroy().  If we find something
      * here then you will get a call to slave_configure(), then the
      * device will be used for however long it is kept around, then when
      * the device is removed from the system (or * possibly at reboot
      * time), you will then get a call to slave_destroy().  This is
      * assuming you implement slave_configure and slave_destroy.
      * However, if you allocate memory and hang it off the device struct,
      * then you must implement the slave_destroy() routine at a minimum
      * in order to avoid leaking memory
      * each time a device is tore down.
      *
      * Status: OPTIONAL
      */
     int (* slave_alloc)(struct scsi_device *);
 
     /*
      * Once the device has responded to an INQUIRY and we know the
      * device is online, we call into the low level driver with the
      * struct scsi_device *.  If the low level device driver implements
      * this function, it *must* perform the task of setting the queue
      * depth on the device.  All other tasks are optional and depend
      * on what the driver supports and various implementation details.
      * 
      * Things currently recommended to be handled at this time include:
      *
      * 1.  Setting the device queue depth.  Proper setting of this is
      *     described in the comments for scsi_change_queue_depth.
      * 2.  Determining if the device supports the various synchronous
      *     negotiation protocols.  The device struct will already have
      *     responded to INQUIRY and the results of the standard items
      *     will have been shoved into the various device flag bits, eg.
      *     device->sdtr will be true if the device supports SDTR messages.
      * 3.  Allocating command structs that the device will need.
      * 4.  Setting the default timeout on this device (if needed).
      * 5.  Anything else the low level driver might want to do on a device
      *     specific setup basis...
      * 6.  Return 0 on success, non-0 on error.  The device will be marked
      *     as offline on error so that no access will occur.  If you return
      *     non-0, your slave_destroy routine will never get called for this
      *     device, so don't leave any loose memory hanging around, clean
      *     up after yourself before returning non-0
      *
      * Status: OPTIONAL
      */
     int (* slave_configure)(struct scsi_device *);
 
     /*
      * Immediately prior to deallocating the device and after all activity
      * has ceased the mid layer calls this point so that the low level
      * driver may completely detach itself from the scsi device and vice
      * versa.  The low level driver is responsible for freeing any memory
      * it allocated in the slave_alloc or slave_configure calls. 
      *
      * Status: OPTIONAL
      */
     void (* slave_destroy)(struct scsi_device *);
 
     /*
      * Before the mid layer attempts to scan for a new device attached
      * to a target where no target currently exists, it will call this
      * entry in your driver.  Should your driver need to allocate any
      * structs or perform any other init items in order to send commands
      * to a currently unused target, then this is where you can perform
      * those allocations.
      *
      * Return values: 0 on success, non-0 on failure
      *
      * Status: OPTIONAL
      */
     int (* target_alloc)(struct scsi_target *);
 
     /*
      * Immediately prior to deallocating the target structure, and
      * after all activity to attached scsi devices has ceased, the
      * midlayer calls this point so that the driver may deallocate
      * and terminate any references to the target.
      *
      * Status: OPTIONAL
      */
     void (* target_destroy)(struct scsi_target *);
 
     /*
      * If a host has the ability to discover targets on its own instead
      * of scanning the entire bus, it can fill in this function and
      * call scsi_scan_host().  This function will be called periodically
      * until it returns 1 with the scsi_host and the elapsed time of
      * the scan in jiffies.
      *
      * Status: OPTIONAL
      */
     int (* scan_finished)(struct Scsi_Host *, unsigned long);
 
     /*
      * If the host wants to be called before the scan starts, but
      * after the midlayer has set up ready for the scan, it can fill
      * in this function.
      *
      * Status: OPTIONAL
      */
     void (* scan_start)(struct Scsi_Host *);
 
     /*
      * Fill in this function to allow the queue depth of this host
      * to be changeable (on a per device basis).  Returns either
      * the current queue depth setting (may be different from what
      * was passed in) or an error.  An error should only be
      * returned if the requested depth is legal but the driver was
      * unable to set it.  If the requested depth is illegal, the
      * driver should set and return the closest legal queue depth.
      *
      * Status: OPTIONAL
      */
     int (* change_queue_depth)(struct scsi_device *, int);
 
     /*
      * This functions lets the driver expose the queue mapping
      * to the block layer.
      *
      * Status: OPTIONAL
      */
     int (* map_queues)(struct Scsi_Host *shost);
 
     /*
      * SCSI interface of blk_poll - poll for IO completions.
      * Only applicable if SCSI LLD exposes multiple h/w queues.
      *
      * Return value: Number of completed entries found.
      *
      * Status: OPTIONAL
      */
     int (* mq_poll)(struct Scsi_Host *shost, unsigned int queue_num);
 
     /*
      * Check if scatterlists need to be padded for DMA draining.
      *
      * Status: OPTIONAL
      */
     bool (* dma_need_drain)(struct request *rq);
 
     /*
      * This function determines the BIOS parameters for a given
      * harddisk.  These tend to be numbers that are made up by
      * the host adapter.  Parameters:
      * size, device, list (heads, sectors, cylinders)
      *
      * Status: OPTIONAL
      */
     int (* bios_param)(struct scsi_device *, struct block_device *,
             sector_t, int []);
 
     /*
      * This function is called when one or more partitions on the
      * device reach beyond the end of the device.
      *
      * Status: OPTIONAL
      */
     void (*unlock_native_capacity)(struct scsi_device *);
 
     /*
      * Can be used to export driver statistics and other infos to the
      * world outside the kernel ie. userspace and it also provides an
      * interface to feed the driver with information.
      *
      * Status: OBSOLETE
      */
     int (*show_info)(struct seq_file *, struct Scsi_Host *);
     int (*write_info)(struct Scsi_Host *, char *, int);
 
     /*
      * This is an optional routine that allows the transport to become
      * involved when a scsi io timer fires. The return value tells the
      * timer routine how to finish the io timeout handling.
      *
      * Status: OPTIONAL
      */
     enum blk_eh_timer_return (*eh_timed_out)(struct scsi_cmnd *);
     /*
      * Optional routine that allows the transport to decide if a cmd
      * is retryable. Return true if the transport is in a state the
      * cmd should be retried on.
      */
     bool (*eh_should_retry_cmd)(struct scsi_cmnd *scmd);
 
     /* This is an optional routine that allows transport to initiate
      * LLD adapter or firmware reset using sysfs attribute.
      *
      * Return values: 0 on success, -ve value on failure.
      *
      * Status: OPTIONAL
      */
 
     int (*host_reset)(struct Scsi_Host *shost, int reset_type);
 #define SCSI_ADAPTER_RESET  1
 #define SCSI_FIRMWARE_RESET 2
 
 
     /*
      * Name of proc directory
      */
     const char *proc_name;
 
     /*
      * Used to store the procfs directory if a driver implements the
      * show_info method.
      */
     struct proc_dir_entry *proc_dir;
 
     /*
      * This determines if we will use a non-interrupt driven
      * or an interrupt driven scheme.  It is set to the maximum number
      * of simultaneous commands a single hw queue in HBA will accept.
      */
     int can_queue;
 
     /*
      * In many instances, especially where disconnect / reconnect are
      * supported, our host also has an ID on the SCSI bus.  If this is
      * the case, then it must be reserved.  Please set this_id to -1 if
      * your setup is in single initiator mode, and the host lacks an
      * ID.
      */
     int this_id;
 
     /*
      * This determines the degree to which the host adapter is capable
      * of scatter-gather.
      */
     unsigned short sg_tablesize;
     unsigned short sg_prot_tablesize;
 
     /*
      * Set this if the host adapter has limitations beside segment count.
      */
     unsigned int max_sectors;
 
     /*
      * Maximum size in bytes of a single segment.
      */
     unsigned int max_segment_size;
 
     /*
      * DMA scatter gather segment boundary limit. A segment crossing this
      * boundary will be split in two.
      */
     unsigned long dma_boundary;
 
     unsigned long virt_boundary_mask;
 
     /*
      * This specifies "machine infinity" for host templates which don't
      * limit the transfer size.  Note this limit represents an absolute
      * maximum, and may be over the transfer limits allowed for
      * individual devices (e.g. 256 for SCSI-1).
      */
 #define SCSI_DEFAULT_MAX_SECTORS    1024
 
     /*
      * True if this host adapter can make good use of linked commands.
      * This will allow more than one command to be queued to a given
      * unit on a given host.  Set this to the maximum number of command
      * blocks to be provided for each device.  Set this to 1 for one
      * command block per lun, 2 for two, etc.  Do not set this to 0.
      * You should make sure that the host adapter will do the right thing
      * before you try setting this above 1.
      */
     short cmd_per_lun;
 
     /*
      * present contains counter indicating how many boards of this
      * type were found when we did the scan.
      */
     unsigned char present;
 
     /* If use block layer to manage tags, this is tag allocation policy */
     int tag_alloc_policy;
 
     /*
      * Track QUEUE_FULL events and reduce queue depth on demand.
      */
     unsigned track_queue_depth:1;
 
     /*
      * This specifies the mode that a LLD supports.
      */
     unsigned supported_mode:2;
 
     /*
      * True for emulated SCSI host adapters (e.g. ATAPI).
      */
     unsigned emulated:1;
 
     /*
      * True if the low-level driver performs its own reset-settle delays.
      */
     unsigned skip_settle_delay:1;
 
     /* True if the controller does not support WRITE SAME */
     unsigned no_write_same:1;
 
     /* True if the host uses host-wide tagspace */
     unsigned host_tagset:1;
 
     /*
      * Countdown for host blocking with no commands outstanding.
      */
     unsigned int max_host_blocked;
 
     /*
      * Default value for the blocking.  If the queue is empty,
      * host_blocked counts down in the request_fn until it restarts
      * host operations as zero is reached.  
      *
      * FIXME: This should probably be a value in the template
      */
 #define SCSI_DEFAULT_HOST_BLOCKED   7
 
     /*
      * Pointer to the SCSI host sysfs attribute groups, NULL terminated.
      */
     const struct attribute_group **shost_groups;
 
     /*
      * Pointer to the SCSI device attribute groups for this host,
      * NULL terminated.
      */
     const struct attribute_group **sdev_groups;
 
     /*
      * Vendor Identifier associated with the host
      *
      * Note: When specifying vendor_id, be sure to read the
      *   Vendor Type and ID formatting requirements specified in
      *   scsi_netlink.h
      */
     u64 vendor_id;
 
     /* Delay for runtime autosuspend */
     int rpm_autosuspend_delay;
 };
 
 /*
  * Temporary #define for host lock push down. Can be removed when all
  * drivers have been updated to take advantage of unlocked
  * queuecommand.
  *
  */
 #define DEF_SCSI_QCMD(func_name) \
     int func_name(struct Scsi_Host *shost, struct scsi_cmnd *cmd)   \
     {                               \
         unsigned long irq_flags;                \
         int rc;                         \
         spin_lock_irqsave(shost->host_lock, irq_flags);     \
         rc = func_name##_lck(cmd);              \
         spin_unlock_irqrestore(shost->host_lock, irq_flags);    \
         return rc;                      \
     }
 
 
 /*
  * shost state: If you alter this, you also need to alter scsi_sysfs.c
  * (for the ascii descriptions) and the state model enforcer:
  * scsi_host_set_state()
  */
 enum scsi_host_state {
     SHOST_CREATED = 1,
     SHOST_RUNNING,
     SHOST_CANCEL,
     SHOST_DEL,
     SHOST_RECOVERY,
     SHOST_CANCEL_RECOVERY,
     SHOST_DEL_RECOVERY,
 };
 
 struct Scsi_Host {
     /*
      * __devices is protected by the host_lock, but you should
      * usually use scsi_device_lookup / shost_for_each_device
      * to access it and don't care about locking yourself.
      * In the rare case of being in irq context you can use
      * their __ prefixed variants with the lock held. NEVER
      * access this list directly from a driver.
      */
     struct list_head    __devices;
     struct list_head    __targets;
     
     struct list_head    starved_list;
 
     spinlock_t      default_lock;
     spinlock_t      *host_lock;
 
     struct mutex        scan_mutex;/* serialize scanning activity */
 
     struct list_head    eh_abort_list;
     struct list_head    eh_cmd_q;
     struct task_struct    * ehandler;  /* Error recovery thread. */
     struct completion     * eh_action; /* Wait for specific actions on the
                           host. */
     wait_queue_head_t       host_wait;
     struct scsi_host_template *hostt;
     struct scsi_transport_template *transportt;
 
     struct kref     tagset_refcnt;
     struct completion   tagset_freed;
     /* Area to keep a shared tag map */
     struct blk_mq_tag_set   tag_set;
 
     atomic_t host_blocked;
 
     unsigned int host_failed;      /* commands that failed.
                           protected by host_lock */
     unsigned int host_eh_scheduled;    /* EH scheduled without command */
     
     unsigned int host_no;  /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
 
     /* next two fields are used to bound the time spent in error handling */
     int eh_deadline;
     unsigned long last_reset;
 
 
     /*
      * These three parameters can be used to allow for wide scsi,
      * and for host adapters that support multiple busses
      * The last two should be set to 1 more than the actual max id
      * or lun (e.g. 8 for SCSI parallel systems).
      */
     unsigned int max_channel;
     unsigned int max_id;
     u64 max_lun;
 
     /*
      * This is a unique identifier that must be assigned so that we
      * have some way of identifying each detected host adapter properly
      * and uniquely.  For hosts that do not support more than one card
      * in the system at one time, this does not need to be set.  It is
      * initialized to 0 in scsi_register.
      */
     unsigned int unique_id;
 
     /*
      * The maximum length of SCSI commands that this host can accept.
      * Probably 12 for most host adapters, but could be 16 for others.
      * or 260 if the driver supports variable length cdbs.
      * For drivers that don't set this field, a value of 12 is
      * assumed.
      */
     unsigned short max_cmd_len;
 
     int this_id;
     int can_queue;
     short cmd_per_lun;
     short unsigned int sg_tablesize;
     short unsigned int sg_prot_tablesize;
     unsigned int max_sectors;
     unsigned int opt_sectors;
     unsigned int max_segment_size;
     unsigned long dma_boundary;
     unsigned long virt_boundary_mask;
     /*
      * In scsi-mq mode, the number of hardware queues supported by the LLD.
      *
      * Note: it is assumed that each hardware queue has a queue depth of
      * can_queue. In other words, the total queue depth per host
      * is nr_hw_queues * can_queue. However, for when host_tagset is set,
      * the total queue depth is can_queue.
      */
     unsigned nr_hw_queues;
     unsigned nr_maps;
     unsigned active_mode:2;
 
     /*
      * Host has requested that no further requests come through for the
      * time being.
      */
     unsigned host_self_blocked:1;
     
     /*
      * Host uses correct SCSI ordering not PC ordering. The bit is
      * set for the minority of drivers whose authors actually read
      * the spec ;).
      */
     unsigned reverse_ordering:1;
 
     /* Task mgmt function in progress */
     unsigned tmf_in_progress:1;
 
     /* Asynchronous scan in progress */
     unsigned async_scan:1;
 
     /* Don't resume host in EH */
     unsigned eh_noresume:1;
 
     /* The controller does not support WRITE SAME */
     unsigned no_write_same:1;
 
     /* True if the host uses host-wide tagspace */
     unsigned host_tagset:1;
 
     /* Host responded with short (<36 bytes) INQUIRY result */
     unsigned short_inquiry:1;
 
     /* The transport requires the LUN bits NOT to be stored in CDB[1] */
     unsigned no_scsi2_lun_in_cdb:1;
 
     /*
      * Optional work queue to be utilized by the transport
      */
     char work_q_name[20];
     struct workqueue_struct *work_q;
 
     /*
      * Task management function work queue
      */
     struct workqueue_struct *tmf_work_q;
 
     /*
      * Value host_blocked counts down from
      */
     unsigned int max_host_blocked;
 
     /* Protection Information */
     unsigned int prot_capabilities;
     unsigned char prot_guard_type;
 
     /* legacy crap */
     unsigned long base;
     unsigned long io_port;
     unsigned char n_io_port;
     unsigned char dma_channel;
     unsigned int  irq;
     
 
     enum scsi_host_state shost_state;
 
     /* ldm bits */
     struct device       shost_gendev, shost_dev;
 
     /*
      * Points to the transport data (if any) which is allocated
      * separately
      */
     void *shost_data;
 
     /*
      * Points to the physical bus device we'd use to do DMA
      * Needed just in case we have virtual hosts.
      */
     struct device *dma_dev;
 
     /*
      * We should ensure that this is aligned, both for better performance
      * and also because some compilers (m68k) don't automatically force
      * alignment to a long boundary.
      */
     unsigned long hostdata[]  /* Used for storage of host specific stuff */
         __attribute__ ((aligned (sizeof(unsigned long))));
 };
 
 #define     class_to_shost(d)   \
     container_of(d, struct Scsi_Host, shost_dev)
 
 #define shost_printk(prefix, shost, fmt, a...)  \
     dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
 
 static inline void *shost_priv(struct Scsi_Host *shost)
 {
     return (void *)shost->hostdata;
 }
 
 int scsi_is_host_device(const struct device *);
 
 static inline struct Scsi_Host *dev_to_shost(struct device *dev)
 {
     while (!scsi_is_host_device(dev)) {
         if (!dev->parent)
             return NULL;
         dev = dev->parent;
     }
     return container_of(dev, struct Scsi_Host, shost_gendev);
 }
 
 static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
 {
     return shost->shost_state == SHOST_RECOVERY ||
         shost->shost_state == SHOST_CANCEL_RECOVERY ||
         shost->shost_state == SHOST_DEL_RECOVERY ||
         shost->tmf_in_progress;
 }
 
 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
 extern void scsi_flush_work(struct Scsi_Host *);
 
 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
 extern int __must_check scsi_add_host_with_dma(struct Scsi_Host *,
                            struct device *,
                            struct device *);
 extern void scsi_scan_host(struct Scsi_Host *);
 extern void scsi_rescan_device(struct device *);
 extern void scsi_remove_host(struct Scsi_Host *);
 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
 extern int scsi_host_busy(struct Scsi_Host *shost);
 extern void scsi_host_put(struct Scsi_Host *t);
 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
 extern const char *scsi_host_state_name(enum scsi_host_state);
 extern void scsi_host_complete_all_commands(struct Scsi_Host *shost,
                         enum scsi_host_status status);
 
 static inline int __must_check scsi_add_host(struct Scsi_Host *host,
                          struct device *dev)
 {
     return scsi_add_host_with_dma(host, dev, dev);
 }
 
 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
 {
         return shost->shost_gendev.parent;
 }
 
 /**
  * scsi_host_scan_allowed - Is scanning of this host allowed
  * @shost:  Pointer to Scsi_Host.
  **/
 static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
 {
     return shost->shost_state == SHOST_RUNNING ||
            shost->shost_state == SHOST_RECOVERY;
 }
 
 extern void scsi_unblock_requests(struct Scsi_Host *);
 extern void scsi_block_requests(struct Scsi_Host *);
 extern int scsi_host_block(struct Scsi_Host *shost);
 extern int scsi_host_unblock(struct Scsi_Host *shost, int new_state);
 
 void scsi_host_busy_iter(struct Scsi_Host *,
              bool (*fn)(struct scsi_cmnd *, void *), void *priv);
 
 struct class_container;
 
 /*
  * DIF defines the exchange of protection information between
  * initiator and SBC block device.
  *
  * DIX defines the exchange of protection information between OS and
  * initiator.
  */
 enum scsi_host_prot_capabilities {
     SHOST_DIF_TYPE1_PROTECTION = 1 << 0, /* T10 DIF Type 1 */
     SHOST_DIF_TYPE2_PROTECTION = 1 << 1, /* T10 DIF Type 2 */
     SHOST_DIF_TYPE3_PROTECTION = 1 << 2, /* T10 DIF Type 3 */
 
     SHOST_DIX_TYPE0_PROTECTION = 1 << 3, /* DIX between OS and HBA only */
     SHOST_DIX_TYPE1_PROTECTION = 1 << 4, /* DIX with DIF Type 1 */
     SHOST_DIX_TYPE2_PROTECTION = 1 << 5, /* DIX with DIF Type 2 */
     SHOST_DIX_TYPE3_PROTECTION = 1 << 6, /* DIX with DIF Type 3 */
 };
 
 /*
  * SCSI hosts which support the Data Integrity Extensions must
  * indicate their capabilities by setting the prot_capabilities using
  * this call.
  */
 static inline void scsi_host_set_prot(struct Scsi_Host *shost, unsigned int mask)
 {
     shost->prot_capabilities = mask;
 }
 
 static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
 {
     return shost->prot_capabilities;
 }
 
 static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
 {
     return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
 }
 
 static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
 {
     static unsigned char cap[] = { 0,
                        SHOST_DIF_TYPE1_PROTECTION,
                        SHOST_DIF_TYPE2_PROTECTION,
                        SHOST_DIF_TYPE3_PROTECTION };
 
     if (target_type >= ARRAY_SIZE(cap))
         return 0;
 
     return shost->prot_capabilities & cap[target_type] ? target_type : 0;
 }
 
 static inline unsigned int scsi_host_dix_capable(struct Scsi_Host *shost, unsigned int target_type)
 {
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
     static unsigned char cap[] = { SHOST_DIX_TYPE0_PROTECTION,
                        SHOST_DIX_TYPE1_PROTECTION,
                        SHOST_DIX_TYPE2_PROTECTION,
                        SHOST_DIX_TYPE3_PROTECTION };
 
     if (target_type >= ARRAY_SIZE(cap))
         return 0;
 
     return shost->prot_capabilities & cap[target_type];
 #endif
     return 0;
 }
 
 /*
  * All DIX-capable initiators must support the T10-mandated CRC
  * checksum.  Controllers can optionally implement the IP checksum
  * scheme which has much lower impact on system performance.  Note
  * that the main rationale for the checksum is to match integrity
  * metadata with data.  Detecting bit errors are a job for ECC memory
  * and buses.
  */
 
 enum scsi_host_guard_type {
     SHOST_DIX_GUARD_CRC = 1 << 0,
     SHOST_DIX_GUARD_IP  = 1 << 1,
 };
 
 static inline void scsi_host_set_guard(struct Scsi_Host *shost, unsigned char type)
 {
     shost->prot_guard_type = type;
 }
 
 static inline unsigned char scsi_host_get_guard(struct Scsi_Host *shost)
 {
     return shost->prot_guard_type;
 }
 
 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
 
 #endif /* _SCSI_SCSI_HOST_H */

This page was automatically generated by the 2.1.0 LXR engine. The LXR team