On 4/12/19 5:30 AM, Ming Lei wrote:
scsi_device's refcount is always grabbed in IO path.
Turns out it isn't necessary, because blk_queue_cleanup() will
drain any in-flight IOs, then cancel timeout/requeue work, and
SCSI's requeue_work is canceled too in __scsi_remove_device().
Also scsi_device won't go away until blk_cleanup_queue() is done.
So don't hold the refcount in IO path, especially the refcount isn't
required in IO path since blk_queue_enter() / blk_queue_exit()
is introduced in the legacy block layer.
Cc: Dongli Zhang <dongli.zh...@oracle.com>
Cc: James Smart <james.sm...@broadcom.com>
Cc: Bart Van Assche <bart.vanass...@wdc.com>
Cc: linux-scsi@vger.kernel.org,
Cc: Martin K . Petersen <martin.peter...@oracle.com>,
Cc: Christoph Hellwig <h...@lst.de>,
Cc: James E . J . Bottomley <j...@linux.vnet.ibm.com>,
Cc: jianchao wang <jianchao.w.w...@oracle.com>
Reviewed-by: Bart Van Assche <bvanass...@acm.org>
Signed-off-by: Ming Lei <ming....@redhat.com>
---
drivers/scsi/scsi_lib.c | 28 ++--------------------------
1 file changed, 2 insertions(+), 26 deletions(-)
Reviewed-by: Hannes Reinecke <h...@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
h...@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)
