scsi: ufs: Optimize SCSI command processing

Use a spinlock to protect hba->outstanding_reqs instead of using atomic
operations to update this member variable.

This patch is a performance improvement because it reduces the number of
atomic operations in the hot path (test_and_clear_bit()) and because it
reduces the lock contention on the SCSI host lock. On my test setup this
patch improves IOPS by about 1%.

Link: https://lore.kernel.org/r/[email protected]
Cc: Adrian Hunter <[email protected]>
Cc: Stanley Chu <[email protected]>
Cc: Can Guo <[email protected]>
Cc: Asutosh Das <[email protected]>
Cc: Avri Altman <[email protected]>
Reviewed-by: Daejun Park <[email protected]>
Reviewed-by: Bean Huo <[email protected]>
Signed-off-by: Bart Van Assche <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

0 files changed, 0 insertions, 0 deletions