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| author | Christoph Hellwig <hch@lst.de> | 2014-01-22 14:49:41 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-07-25 07:39:00 -0400 |
| commit | 7ae65c0f9646c29432b69580b80e08632e6cd813 (patch) | |
| tree | 9b4cf362095370eeb5c42d21dc33746d0ba088bd /include | |
| parent | cf68d334dd3a323624f6399dc807d34d8b816391 (diff) | |
| download | linux-7ae65c0f9646c29432b69580b80e08632e6cd813.tar.gz linux-7ae65c0f9646c29432b69580b80e08632e6cd813.tar.bz2 linux-7ae65c0f9646c29432b69580b80e08632e6cd813.zip | |
scsi: convert target_busy to an atomic_t
Avoid taking the host-wide host_lock to check the per-target 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 'include')
| -rw-r--r-- | include/scsi/scsi_device.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 9aa38f7b303b..4e078b63a9e5 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -291,8 +291,8 @@ struct scsi_target { unsigned int expecting_lun_change:1; /* A device has reported * a 3F/0E UA, other devices on * the same target will also. */ - /* commands actually active on LLD. protected by host lock. */ - unsigned int target_busy; + /* commands actually active on LLD. */ + atomic_t target_busy; /* * LLDs should set this in the slave_alloc host template callout. * If set to zero then there is not limit. |