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	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-only
 /*
  * fs/nfs/nfs4session.c
  *
  * Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
  *
  */
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/printk.h>
 #include <linux/slab.h>
 #include <linux/sunrpc/sched.h>
 #include <linux/sunrpc/bc_xprt.h>
 #include <linux/nfs.h>
 #include <linux/nfs4.h>
 #include <linux/nfs_fs.h>
 #include <linux/module.h>
 
 #include "nfs4_fs.h"
 #include "internal.h"
 #include "nfs4session.h"
 #include "callback.h"
 
 #define NFSDBG_FACILITY     NFSDBG_STATE
 
 static void nfs4_init_slot_table(struct nfs4_slot_table *tbl, const char *queue)
 {
     tbl->highest_used_slotid = NFS4_NO_SLOT;
     spin_lock_init(&tbl->slot_tbl_lock);
     rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, queue);
     init_waitqueue_head(&tbl->slot_waitq);
     init_completion(&tbl->complete);
 }
 
 /*
  * nfs4_shrink_slot_table - free retired slots from the slot table
  */
 static void nfs4_shrink_slot_table(struct nfs4_slot_table  *tbl, u32 newsize)
 {
     struct nfs4_slot **p;
     if (newsize >= tbl->max_slots)
         return;
 
     p = &tbl->slots;
     while (newsize--)
         p = &(*p)->next;
     while (*p) {
         struct nfs4_slot *slot = *p;
 
         *p = slot->next;
         kfree(slot);
         tbl->max_slots--;
     }
 }
 
 /**
  * nfs4_slot_tbl_drain_complete - wake waiters when drain is complete
  * @tbl: controlling slot table
  *
  */
 void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl)
 {
     if (nfs4_slot_tbl_draining(tbl))
         complete(&tbl->complete);
 }
 
 /*
  * nfs4_free_slot - free a slot and efficiently update slot table.
  *
  * freeing a slot is trivially done by clearing its respective bit
  * in the bitmap.
  * If the freed slotid equals highest_used_slotid we want to update it
  * so that the server would be able to size down the slot table if needed,
  * otherwise we know that the highest_used_slotid is still in use.
  * When updating highest_used_slotid there may be "holes" in the bitmap
  * so we need to scan down from highest_used_slotid to 0 looking for the now
  * highest slotid in use.
  * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
  *
  * Must be called while holding tbl->slot_tbl_lock
  */
 void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
 {
     u32 slotid = slot->slot_nr;
 
     /* clear used bit in bitmap */
     __clear_bit(slotid, tbl->used_slots);
 
     /* update highest_used_slotid when it is freed */
     if (slotid == tbl->highest_used_slotid) {
         u32 new_max = find_last_bit(tbl->used_slots, slotid);
         if (new_max < slotid)
             tbl->highest_used_slotid = new_max;
         else {
             tbl->highest_used_slotid = NFS4_NO_SLOT;
             nfs4_slot_tbl_drain_complete(tbl);
         }
     }
     dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
         slotid, tbl->highest_used_slotid);
 }
 
 static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table  *tbl,
         u32 slotid, u32 seq_init, gfp_t gfp_mask)
 {
     struct nfs4_slot *slot;
 
     slot = kzalloc(sizeof(*slot), gfp_mask);
     if (slot) {
         slot->table = tbl;
         slot->slot_nr = slotid;
         slot->seq_nr = seq_init;
         slot->seq_nr_highest_sent = seq_init;
         slot->seq_nr_last_acked = seq_init - 1;
     }
     return slot;
 }
 
 static struct nfs4_slot *nfs4_find_or_create_slot(struct nfs4_slot_table  *tbl,
         u32 slotid, u32 seq_init, gfp_t gfp_mask)
 {
     struct nfs4_slot **p, *slot;
 
     p = &tbl->slots;
     for (;;) {
         if (*p == NULL) {
             *p = nfs4_new_slot(tbl, tbl->max_slots,
                     seq_init, gfp_mask);
             if (*p == NULL)
                 break;
             tbl->max_slots++;
         }
         slot = *p;
         if (slot->slot_nr == slotid)
             return slot;
         p = &slot->next;
     }
     return ERR_PTR(-ENOMEM);
 }
 
 static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
         struct nfs4_slot *slot)
 {
     u32 slotid = slot->slot_nr;
 
     __set_bit(slotid, tbl->used_slots);
     if (slotid > tbl->highest_used_slotid ||
         tbl->highest_used_slotid == NFS4_NO_SLOT)
         tbl->highest_used_slotid = slotid;
     slot->generation = tbl->generation;
 }
 
 /*
  * nfs4_try_to_lock_slot - Given a slot try to allocate it
  *
  * Note: must be called with the slot_tbl_lock held.
  */
 bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
 {
     if (nfs4_test_locked_slot(tbl, slot->slot_nr))
         return false;
     nfs4_lock_slot(tbl, slot);
     return true;
 }
 
 /*
  * nfs4_lookup_slot - Find a slot but don't allocate it
  *
  * Note: must be called with the slot_tbl_lock held.
  */
 struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
 {
     if (slotid <= tbl->max_slotid)
         return nfs4_find_or_create_slot(tbl, slotid, 0, GFP_NOWAIT);
     return ERR_PTR(-E2BIG);
 }
 
 static int nfs4_slot_get_seqid(struct nfs4_slot_table  *tbl, u32 slotid,
         u32 *seq_nr)
     __must_hold(&tbl->slot_tbl_lock)
 {
     struct nfs4_slot *slot;
     int ret;
 
     slot = nfs4_lookup_slot(tbl, slotid);
     ret = PTR_ERR_OR_ZERO(slot);
     if (!ret)
         *seq_nr = slot->seq_nr;
 
     return ret;
 }
 
 /*
  * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
  *
  * Given a slot table, slot id and sequence number, determine if the
  * RPC call in question is still in flight. This function is mainly
  * intended for use by the callback channel.
  */
 static bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl,
         u32 slotid, u32 seq_nr)
 {
     u32 cur_seq = 0;
     bool ret = false;
 
     spin_lock(&tbl->slot_tbl_lock);
     if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
         cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
         ret = true;
     spin_unlock(&tbl->slot_tbl_lock);
     return ret;
 }
 
 /*
  * nfs4_slot_wait_on_seqid - wait until a slot sequence id is complete
  *
  * Given a slot table, slot id and sequence number, wait until the
  * corresponding RPC call completes. This function is mainly
  * intended for use by the callback channel.
  */
 int nfs4_slot_wait_on_seqid(struct nfs4_slot_table *tbl,
         u32 slotid, u32 seq_nr,
         unsigned long timeout)
 {
     if (wait_event_timeout(tbl->slot_waitq,
             !nfs4_slot_seqid_in_use(tbl, slotid, seq_nr),
             timeout) == 0)
         return -ETIMEDOUT;
     return 0;
 }
 
 /*
  * nfs4_alloc_slot - efficiently look for a free slot
  *
  * nfs4_alloc_slot looks for an unset bit in the used_slots bitmap.
  * If found, we mark the slot as used, update the highest_used_slotid,
  * and respectively set up the sequence operation args.
  *
  * Note: must be called with under the slot_tbl_lock.
  */
 struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
 {
     struct nfs4_slot *ret = ERR_PTR(-EBUSY);
     u32 slotid;
 
     dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
         __func__, tbl->used_slots[0], tbl->highest_used_slotid,
         tbl->max_slotid + 1);
     slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
     if (slotid <= tbl->max_slotid) {
         ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
         if (!IS_ERR(ret))
             nfs4_lock_slot(tbl, ret);
     }
     dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
         __func__, tbl->used_slots[0], tbl->highest_used_slotid,
         !IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
     return ret;
 }
 
 static int nfs4_grow_slot_table(struct nfs4_slot_table *tbl,
          u32 max_reqs, u32 ivalue)
 {
     if (max_reqs <= tbl->max_slots)
         return 0;
     if (!IS_ERR(nfs4_find_or_create_slot(tbl, max_reqs - 1, ivalue, GFP_NOFS)))
         return 0;
     return -ENOMEM;
 }
 
 static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
         u32 server_highest_slotid,
         u32 ivalue)
 {
     struct nfs4_slot **p;
 
     nfs4_shrink_slot_table(tbl, server_highest_slotid + 1);
     p = &tbl->slots;
     while (*p) {
         (*p)->seq_nr = ivalue;
         (*p)->seq_nr_highest_sent = ivalue;
         (*p)->seq_nr_last_acked = ivalue - 1;
         p = &(*p)->next;
     }
     tbl->highest_used_slotid = NFS4_NO_SLOT;
     tbl->target_highest_slotid = server_highest_slotid;
     tbl->server_highest_slotid = server_highest_slotid;
     tbl->d_target_highest_slotid = 0;
     tbl->d2_target_highest_slotid = 0;
     tbl->max_slotid = server_highest_slotid;
 }
 
 /*
  * (re)Initialise a slot table
  */
 static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl,
         u32 max_reqs, u32 ivalue)
 {
     int ret;
 
     dprintk("--> %s: max_reqs=%u, tbl->max_slots %u\n", __func__,
         max_reqs, tbl->max_slots);
 
     if (max_reqs > NFS4_MAX_SLOT_TABLE)
         max_reqs = NFS4_MAX_SLOT_TABLE;
 
     ret = nfs4_grow_slot_table(tbl, max_reqs, ivalue);
     if (ret)
         goto out;
 
     spin_lock(&tbl->slot_tbl_lock);
     nfs4_reset_slot_table(tbl, max_reqs - 1, ivalue);
     spin_unlock(&tbl->slot_tbl_lock);
 
     dprintk("%s: tbl=%p slots=%p max_slots=%u\n", __func__,
         tbl, tbl->slots, tbl->max_slots);
 out:
     dprintk("<-- %s: return %d\n", __func__, ret);
     return ret;
 }
 
 /*
  * nfs4_release_slot_table - release all slot table entries
  */
 static void nfs4_release_slot_table(struct nfs4_slot_table *tbl)
 {
     nfs4_shrink_slot_table(tbl, 0);
 }
 
 /**
  * nfs4_shutdown_slot_table - release resources attached to a slot table
  * @tbl: slot table to shut down
  *
  */
 void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl)
 {
     nfs4_release_slot_table(tbl);
     rpc_destroy_wait_queue(&tbl->slot_tbl_waitq);
 }
 
 /**
  * nfs4_setup_slot_table - prepare a stand-alone slot table for use
  * @tbl: slot table to set up
  * @max_reqs: maximum number of requests allowed
  * @queue: name to give RPC wait queue
  *
  * Returns zero on success, or a negative errno.
  */
 int nfs4_setup_slot_table(struct nfs4_slot_table *tbl, unsigned int max_reqs,
         const char *queue)
 {
     nfs4_init_slot_table(tbl, queue);
     return nfs4_realloc_slot_table(tbl, max_reqs, 0);
 }
 
 static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
 {
     struct nfs4_sequence_args *args = task->tk_msg.rpc_argp;
     struct nfs4_sequence_res *res = task->tk_msg.rpc_resp;
     struct nfs4_slot *slot = pslot;
     struct nfs4_slot_table *tbl = slot->table;
 
     if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
         return false;
     slot->generation = tbl->generation;
     args->sa_slot = slot;
     res->sr_timestamp = jiffies;
     res->sr_slot = slot;
     res->sr_status_flags = 0;
     res->sr_status = 1;
     return true;
 }
 
 static bool __nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
         struct nfs4_slot *slot)
 {
     if (rpc_wake_up_first(&tbl->slot_tbl_waitq, nfs41_assign_slot, slot))
         return true;
     return false;
 }
 
 bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
         struct nfs4_slot *slot)
 {
     if (slot->slot_nr > tbl->max_slotid)
         return false;
     return __nfs41_wake_and_assign_slot(tbl, slot);
 }
 
 static bool nfs41_try_wake_next_slot_table_entry(struct nfs4_slot_table *tbl)
 {
     struct nfs4_slot *slot = nfs4_alloc_slot(tbl);
     if (!IS_ERR(slot)) {
         bool ret = __nfs41_wake_and_assign_slot(tbl, slot);
         if (ret)
             return ret;
         nfs4_free_slot(tbl, slot);
     }
     return false;
 }
 
 void nfs41_wake_slot_table(struct nfs4_slot_table *tbl)
 {
     for (;;) {
         if (!nfs41_try_wake_next_slot_table_entry(tbl))
             break;
     }
 }
 
 #if defined(CONFIG_NFS_V4_1)
 
 static void nfs41_set_max_slotid_locked(struct nfs4_slot_table *tbl,
         u32 target_highest_slotid)
 {
     u32 max_slotid;
 
     max_slotid = min(NFS4_MAX_SLOT_TABLE - 1, target_highest_slotid);
     if (max_slotid > tbl->server_highest_slotid)
         max_slotid = tbl->server_highest_slotid;
     if (max_slotid > tbl->target_highest_slotid)
         max_slotid = tbl->target_highest_slotid;
     tbl->max_slotid = max_slotid;
     nfs41_wake_slot_table(tbl);
 }
 
 /* Update the client's idea of target_highest_slotid */
 static void nfs41_set_target_slotid_locked(struct nfs4_slot_table *tbl,
         u32 target_highest_slotid)
 {
     if (tbl->target_highest_slotid == target_highest_slotid)
         return;
     tbl->target_highest_slotid = target_highest_slotid;
     tbl->generation++;
 }
 
 void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
         u32 target_highest_slotid)
 {
     spin_lock(&tbl->slot_tbl_lock);
     nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
     tbl->d_target_highest_slotid = 0;
     tbl->d2_target_highest_slotid = 0;
     nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
     spin_unlock(&tbl->slot_tbl_lock);
 }
 
 static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
         u32 highest_slotid)
 {
     if (tbl->server_highest_slotid == highest_slotid)
         return;
     if (tbl->highest_used_slotid > highest_slotid)
         return;
     /* Deallocate slots */
     nfs4_shrink_slot_table(tbl, highest_slotid + 1);
     tbl->server_highest_slotid = highest_slotid;
 }
 
 static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
 {
     s1 -= s2;
     if (s1 == 0)
         return 0;
     if (s1 < 0)
         return (s1 - 1) >> 1;
     return (s1 + 1) >> 1;
 }
 
 static int nfs41_sign_s32(s32 s1)
 {
     if (s1 > 0)
         return 1;
     if (s1 < 0)
         return -1;
     return 0;
 }
 
 static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
 {
     if (!s1 || !s2)
         return true;
     return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
 }
 
 /* Try to eliminate outliers by checking for sharp changes in the
  * derivatives and second derivatives
  */
 static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
         u32 new_target)
 {
     s32 d_target, d2_target;
     bool ret = true;
 
     d_target = nfs41_derivative_target_slotid(new_target,
             tbl->target_highest_slotid);
     d2_target = nfs41_derivative_target_slotid(d_target,
             tbl->d_target_highest_slotid);
     /* Is first derivative same sign? */
     if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
         ret = false;
     /* Is second derivative same sign? */
     if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
         ret = false;
     tbl->d_target_highest_slotid = d_target;
     tbl->d2_target_highest_slotid = d2_target;
     return ret;
 }
 
 void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
         struct nfs4_slot *slot,
         struct nfs4_sequence_res *res)
 {
     u32 target_highest_slotid = min(res->sr_target_highest_slotid,
                     NFS4_MAX_SLOTID);
     u32 highest_slotid = min(res->sr_highest_slotid, NFS4_MAX_SLOTID);
 
     spin_lock(&tbl->slot_tbl_lock);
     if (!nfs41_is_outlier_target_slotid(tbl, target_highest_slotid))
         nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
     if (tbl->generation == slot->generation)
         nfs41_set_server_slotid_locked(tbl, highest_slotid);
     nfs41_set_max_slotid_locked(tbl, target_highest_slotid);
     spin_unlock(&tbl->slot_tbl_lock);
 }
 
 static void nfs4_release_session_slot_tables(struct nfs4_session *session)
 {
     nfs4_release_slot_table(&session->fc_slot_table);
     nfs4_release_slot_table(&session->bc_slot_table);
 }
 
 /*
  * Initialize or reset the forechannel and backchannel tables
  */
 int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
 {
     struct nfs4_slot_table *tbl;
     int status;
 
     dprintk("--> %s\n", __func__);
     /* Fore channel */
     tbl = &ses->fc_slot_table;
     tbl->session = ses;
     status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
     if (status || !(ses->flags & SESSION4_BACK_CHAN)) /* -ENOMEM */
         return status;
     /* Back channel */
     tbl = &ses->bc_slot_table;
     tbl->session = ses;
     status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
     if (status && tbl->slots == NULL)
         /* Fore and back channel share a connection so get
          * both slot tables or neither */
         nfs4_release_session_slot_tables(ses);
     return status;
 }
 
 struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
 {
     struct nfs4_session *session;
 
     session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
     if (!session)
         return NULL;
 
     nfs4_init_slot_table(&session->fc_slot_table, "ForeChannel Slot table");
     nfs4_init_slot_table(&session->bc_slot_table, "BackChannel Slot table");
     session->session_state = 1<<NFS4_SESSION_INITING;
 
     session->clp = clp;
     return session;
 }
 
 static void nfs4_destroy_session_slot_tables(struct nfs4_session *session)
 {
     nfs4_shutdown_slot_table(&session->fc_slot_table);
     nfs4_shutdown_slot_table(&session->bc_slot_table);
 }
 
 void nfs4_destroy_session(struct nfs4_session *session)
 {
     struct rpc_xprt *xprt;
     const struct cred *cred;
 
     cred = nfs4_get_clid_cred(session->clp);
     nfs4_proc_destroy_session(session, cred);
     put_cred(cred);
 
     rcu_read_lock();
     xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
     rcu_read_unlock();
     dprintk("%s Destroy backchannel for xprt %p\n",
         __func__, xprt);
     xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
     nfs4_destroy_session_slot_tables(session);
     kfree(session);
 }
 
 /*
  * With sessions, the client is not marked ready until after a
  * successful EXCHANGE_ID and CREATE_SESSION.
  *
  * Map errors cl_cons_state errors to EPROTONOSUPPORT to indicate
  * other versions of NFS can be tried.
  */
 static int nfs41_check_session_ready(struct nfs_client *clp)
 {
     int ret;
     
     if (clp->cl_cons_state == NFS_CS_SESSION_INITING) {
         ret = nfs4_client_recover_expired_lease(clp);
         if (ret)
             return ret;
     }
     if (clp->cl_cons_state < NFS_CS_READY)
         return -EPROTONOSUPPORT;
     smp_rmb();
     return 0;
 }
 
 int nfs4_init_session(struct nfs_client *clp)
 {
     if (!nfs4_has_session(clp))
         return 0;
 
     clear_bit(NFS4_SESSION_INITING, &clp->cl_session->session_state);
     return nfs41_check_session_ready(clp);
 }
 
 int nfs4_init_ds_session(struct nfs_client *clp, unsigned long lease_time)
 {
     struct nfs4_session *session = clp->cl_session;
     int ret;
 
     spin_lock(&clp->cl_lock);
     if (test_and_clear_bit(NFS4_SESSION_INITING, &session->session_state)) {
         /*
          * Do not set NFS_CS_CHECK_LEASE_TIME instead set the
          * DS lease to be equal to the MDS lease.
          */
         clp->cl_lease_time = lease_time;
         clp->cl_last_renewal = jiffies;
     }
     spin_unlock(&clp->cl_lock);
 
     ret = nfs41_check_session_ready(clp);
     if (ret)
         return ret;
     /* Test for the DS role */
     if (!is_ds_client(clp))
         return -ENODEV;
     return 0;
 }
 EXPORT_SYMBOL_GPL(nfs4_init_ds_session);
 
 #endif  /* defined(CONFIG_NFS_V4_1) */

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