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.zhang@xxxxxxxxxx> Cc: James Smart <james.smart@xxxxxxxxxxxx> Cc: Bart Van Assche <bart.vanassche@xxxxxxx> Cc: linux-scsi@xxxxxxxxxxxxxxx, Cc: Martin K . Petersen <martin.petersen@xxxxxxxxxx>, Cc: Christoph Hellwig <hch@xxxxxx>, Cc: James E . J . Bottomley <jejb@xxxxxxxxxxxxxxxxxx>, Cc: jianchao wang <jianchao.w.wang@xxxxxxxxxx> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- drivers/scsi/scsi_lib.c | 28 ++-------------------------- 1 file changed, 2 insertions(+), 26 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx> Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg)
