On Wed, 2021-07-21 at 20:34 -0700, Bart Van Assche wrote:

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%.



Cc: Adrian Hunter <adrian.hunter@intel.com>

Cc: Stanley Chu <redacted>

Cc: Can Guo <redacted>

Cc: Asutosh Das <redacted>

Cc: Avri Altman <avri.altman@wdc.com>

Signed-off-by: Bart Van Assche <bvanassche@acm.org>

Reviewed-by: Bean Huo <redacted>