@@ -563,35 +563,13 @@ struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
}
EXPORT_SYMBOL(scsi_host_get);
-struct scsi_host_mq_in_flight {
- int cnt;
-};
-
-static void scsi_host_check_in_flight(struct request *rq, void *data,
- bool reserved)
-{
- struct scsi_host_mq_in_flight *in_flight = data;
-
- if (blk_mq_request_started(rq))
- in_flight->cnt++;
-}
-
/**
* scsi_host_busy - Return the host busy counter
* @shost: Pointer to Scsi_Host to inc.
**/
int scsi_host_busy(struct Scsi_Host *shost)
{
- struct scsi_host_mq_in_flight in_flight = {
- .cnt = 0,
- };
-
- if (!shost->use_blk_mq)
- return atomic_read(&shost->host_busy);
-
- blk_mq_tagset_busy_iter(&shost->tag_set, scsi_host_check_in_flight,
- &in_flight);
- return in_flight.cnt;
+ return atomic_read(&shost->host_busy);
}
EXPORT_SYMBOL(scsi_host_busy);
@@ -345,8 +345,7 @@ static void scsi_dec_host_busy(struct Scsi_Host *shost)
unsigned long flags;
rcu_read_lock();
- if (!shost->use_blk_mq)
- atomic_dec(&shost->host_busy);
+ atomic_dec(&shost->host_busy);
if (unlikely(scsi_host_in_recovery(shost))) {
spin_lock_irqsave(shost->host_lock, flags);
if (shost->host_failed || shost->host_eh_scheduled)
@@ -445,12 +444,7 @@ static inline bool scsi_target_is_busy(struct scsi_target *starget)
static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
{
- /*
- * blk-mq can handle host queue busy efficiently via host-wide driver
- * tag allocation
- */
-
- if (!shost->use_blk_mq && shost->can_queue > 0 &&
+ if (shost->can_queue > 0 &&
atomic_read(&shost->host_busy) >= shost->can_queue)
return true;
if (atomic_read(&shost->host_blocked) > 0)
@@ -1606,12 +1600,9 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
if (scsi_host_in_recovery(shost))
return 0;
- if (!shost->use_blk_mq)
- busy = atomic_inc_return(&shost->host_busy) - 1;
- else
- busy = 0;
+ busy = atomic_inc_return(&shost->host_busy) - 1;
if (atomic_read(&shost->host_blocked) > 0) {
- if (busy || scsi_host_busy(shost))
+ if (busy)
goto starved;
/*
@@ -1625,7 +1616,7 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
"unblocking host at zero depth\n"));
}
- if (!shost->use_blk_mq && shost->can_queue > 0 && busy >= shost->can_queue)
+ if (shost->can_queue > 0 && busy >= shost->can_queue)
goto starved;
if (shost->host_self_blocked)
goto starved;
@@ -1711,9 +1702,7 @@ static void scsi_kill_request(struct request *req, struct request_queue *q)
* with the locks as normal issue path does.
*/
atomic_inc(&sdev->device_busy);
-
- if (!shost->use_blk_mq)
- atomic_inc(&shost->host_busy);
+ atomic_inc(&shost->host_busy);
if (starget->can_queue > 0)
atomic_inc(&starget->target_busy);
This reverts commit 328728630d9f2bf14b82ca30b5e47489beefe361. There is fundamental issue in commit 328728630d9f2bf1 (scsi: core: avoid host-wide host_busy counter for scsi_mq) because SCSI's host busy counter may not be same with counter of blk-mq's inflight tags, especially in case of none io scheduler. We may switch to other approach for addressing this scsi_mq's performance issue, such as percpu counter or kind of ways, so revert this commit first for fixing this kind of issue in EH path, as reported by Jens. Cc: Omar Sandoval <osandov@fb.com>, Cc: "Martin K. Petersen" <martin.petersen@oracle.com>, Cc: James Bottomley <james.bottomley@hansenpartnership.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: Don Brace <don.brace@microsemi.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Laurence Oberman <loberman@redhat.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: Jens Axboe <axboe@kernel.dk> Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- drivers/scsi/hosts.c | 24 +----------------------- drivers/scsi/scsi_lib.c | 23 ++++++----------------- 2 files changed, 7 insertions(+), 40 deletions(-)