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authorChristoph Hellwig <hch@lst.de>2014-01-22 15:29:29 +0100
committerChristoph Hellwig <hch@lst.de>2014-07-25 07:43:43 -0400
commit74665016086615bbaa3fa6f83af410a0a4e029ee (patch)
tree9f9d8a692bec91dce69fd303eeedf16c35b41ac6 /drivers/scsi/libsas
parent7ae65c0f9646c29432b69580b80e08632e6cd813 (diff)
scsi: convert host_busy to atomic_t
Avoid taking the host-wide host_lock to check the per-host queue limit. Instead we do an atomic_inc_return early on to grab our slot in the queue, and if necessary decrement it after finishing all checks. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
Diffstat (limited to 'drivers/scsi/libsas')
-rw-r--r--drivers/scsi/libsas/sas_scsi_host.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 7d02a19419a7..24e477d2ea70 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -813,7 +813,7 @@ retry:
spin_unlock_irq(shost->host_lock);
SAS_DPRINTK("Enter %s busy: %d failed: %d\n",
- __func__, shost->host_busy, shost->host_failed);
+ __func__, atomic_read(&shost->host_busy), shost->host_failed);
/*
* Deal with commands that still have SAS tasks (i.e. they didn't
* complete via the normal sas_task completion mechanism),
@@ -858,7 +858,8 @@ out:
goto retry;
SAS_DPRINTK("--- Exit %s: busy: %d failed: %d tries: %d\n",
- __func__, shost->host_busy, shost->host_failed, tries);
+ __func__, atomic_read(&shost->host_busy),
+ shost->host_failed, tries);
}
enum blk_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *cmd)