Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI updates from James Bottomley:
 "This is mostly update of the usual drivers: aacraid, ufs, zfcp,
  NCR5380, lpfc, qla2xxx, smartpqi, hisi_sas, target, mpt3sas, pm80xx
  plus a whole load of minor updates and fixes.

  The major core changes are Al Viro's reworking of sg's handling of
  copy to/from user, Ming Lei's removal of the host busy counter to
  avoid contention in the multiqueue case and Damien Le Moal's fixing of
  residual tracking across error handling"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (251 commits)
  scsi: bnx2fc: timeout calculation invalid for bnx2fc_eh_abort()
  scsi: target: core: Fix a pr_debug() argument
  scsi: iscsi: Don't send data to unbound connection
  scsi: target: iscsi: Wait for all commands to finish before freeing a session
  scsi: target: core: Release SPC-2 reservations when closing a session
  scsi: target: core: Document target_cmd_size_check()
  scsi: bnx2i: fix potential use after free
  Revert "scsi: qla2xxx: Fix memory leak when sending I/O fails"
  scsi: NCR5380: Add disconnect_mask module parameter
  scsi: NCR5380: Unconditionally clear ICR after do_abort()
  scsi: NCR5380: Call scsi_set_resid() on command completion
  scsi: scsi_debug: num_tgts must be >= 0
  scsi: lpfc: use hdwq assigned cpu for allocation
  scsi: arcmsr: fix indentation issues
  scsi: qla4xxx: fix double free bug
  scsi: pm80xx: Modified the logic to collect fatal dump
  scsi: pm80xx: Tie the interrupt name to the module instance
  scsi: pm80xx: Controller fatal error through sysfs
  scsi: pm80xx: Do not request 12G sas speeds
  scsi: pm80xx: Cleanup command when a reset times out
  ...

1 files changed, 22 insertions, 23 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 91c007d26c1e..3e7a45d0daca 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -189,7 +189,7 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
 	 * active on the host/device.
 	 */
 	if (unbusy)
-		scsi_device_unbusy(device);
+		scsi_device_unbusy(device, cmd);
 
 	/*
 	 * Requeue this command.  It will go before all other commands
@@ -321,20 +321,20 @@ static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
 }
 
 /*
- * Decrement the host_busy counter and wake up the error handler if necessary.
- * Avoid as follows that the error handler is not woken up if shost->host_busy
- * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
- * with an RCU read lock in this function to ensure that this function in its
- * entirety either finishes before scsi_eh_scmd_add() increases the
+ * Wake up the error handler if necessary. Avoid as follows that the error
+ * handler is not woken up if host in-flight requests number ==
+ * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
+ * with an RCU read lock in this function to ensure that this function in
+ * its entirety either finishes before scsi_eh_scmd_add() increases the
  * host_failed counter or that it notices the shost state change made by
  * scsi_eh_scmd_add().
  */
-static void scsi_dec_host_busy(struct Scsi_Host *shost)
+static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 {
 	unsigned long flags;
 
 	rcu_read_lock();
-	atomic_dec(&shost->host_busy);
+	__clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
 	if (unlikely(scsi_host_in_recovery(shost))) {
 		spin_lock_irqsave(shost->host_lock, flags);
 		if (shost->host_failed || shost->host_eh_scheduled)
@@ -344,12 +344,12 @@ static void scsi_dec_host_busy(struct Scsi_Host *shost)
 	rcu_read_unlock();
 }
 
-void scsi_device_unbusy(struct scsi_device *sdev)
+void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
 {
 	struct Scsi_Host *shost = sdev->host;
 	struct scsi_target *starget = scsi_target(sdev);
 
-	scsi_dec_host_busy(shost);
+	scsi_dec_host_busy(shost, cmd);
 
 	if (starget->can_queue > 0)
 		atomic_dec(&starget->target_busy);
@@ -430,9 +430,6 @@ static inline bool scsi_target_is_busy(struct scsi_target *starget)
 
 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
 {
-	if (shost->can_queue > 0 &&
-	    atomic_read(&shost->host_busy) >= shost->can_queue)
-		return true;
 	if (atomic_read(&shost->host_blocked) > 0)
 		return true;
 	if (shost->host_self_blocked)
@@ -1139,6 +1136,7 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
 	unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
 	unsigned long jiffies_at_alloc;
 	int retries;
+	bool in_flight;
 
 	if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
 		flags |= SCMD_INITIALIZED;
@@ -1147,6 +1145,7 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
 
 	jiffies_at_alloc = cmd->jiffies_at_alloc;
 	retries = cmd->retries;
+	in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
 	/* zero out the cmd, except for the embedded scsi_request */
 	memset((char *)cmd + sizeof(cmd->req), 0,
 		sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
@@ -1158,6 +1157,8 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
 	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
 	cmd->jiffies_at_alloc = jiffies_at_alloc;
 	cmd->retries = retries;
+	if (in_flight)
+		__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
 
 	scsi_add_cmd_to_list(cmd);
 }
@@ -1367,16 +1368,14 @@ out_dec:
  */
 static inline int scsi_host_queue_ready(struct request_queue *q,
 				   struct Scsi_Host *shost,
-				   struct scsi_device *sdev)
+				   struct scsi_device *sdev,
+				   struct scsi_cmnd *cmd)
 {
-	unsigned int busy;
-
 	if (scsi_host_in_recovery(shost))
 		return 0;
 
-	busy = atomic_inc_return(&shost->host_busy) - 1;
 	if (atomic_read(&shost->host_blocked) > 0) {
-		if (busy)
+		if (scsi_host_busy(shost) > 0)
 			goto starved;
 
 		/*
@@ -1390,8 +1389,6 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
 				     "unblocking host at zero depth\n"));
 	}
 
-	if (shost->can_queue > 0 && busy >= shost->can_queue)
-		goto starved;
 	if (shost->host_self_blocked)
 		goto starved;
 
@@ -1403,6 +1400,8 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
 		spin_unlock_irq(shost->host_lock);
 	}
 
+	__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
+
 	return 1;
 
 starved:
@@ -1411,7 +1410,7 @@ starved:
 		list_add_tail(&sdev->starved_entry, &shost->starved_list);
 	spin_unlock_irq(shost->host_lock);
 out_dec:
-	scsi_dec_host_busy(shost);
+	scsi_dec_host_busy(shost, cmd);
 	return 0;
 }
 
@@ -1665,7 +1664,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	ret = BLK_STS_RESOURCE;
 	if (!scsi_target_queue_ready(shost, sdev))
 		goto out_put_budget;
-	if (!scsi_host_queue_ready(q, shost, sdev))
+	if (!scsi_host_queue_ready(q, shost, sdev, cmd))
 		goto out_dec_target_busy;
 
 	if (!(req->rq_flags & RQF_DONTPREP)) {
@@ -1697,7 +1696,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	return BLK_STS_OK;
 
 out_dec_host_busy:
-	scsi_dec_host_busy(shost);
+	scsi_dec_host_busy(shost, cmd);
 out_dec_target_busy:
 	if (scsi_target(sdev)->can_queue > 0)
 		atomic_dec(&scsi_target(sdev)->target_busy);