On Tue, Aug 07, 2018 at 11:24:06PM +0000, Bart Van Assche wrote:

On Wed, 2018-08-08 at 01:44 +0800, Ming Lei wrote:

quoted

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 435347f58328..52e498fb6280 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c

@@ -1971,10 +1971,9 @@ static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost)
 		sizeof(struct scatterlist);
 }
 
-static int scsi_mq_prep_fn(struct request *req)
+static int scsi_mq_prep_fn(struct scsi_device *sdev, struct request *req)
 {
 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
-	struct scsi_device *sdev = req->q->queuedata;
 	struct Scsi_Host *shost = sdev->host;
 	struct scatterlist *sg;
 

@@ -2070,7 +2069,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 		goto out_dec_target_busy;
 
 	if (!(req->rq_flags & RQF_DONTPREP)) {
-		ret = prep_to_mq(scsi_mq_prep_fn(req));
+		ret = prep_to_mq(scsi_mq_prep_fn(sdev, req));
 		if (ret != BLK_STS_OK)
 			goto out_dec_host_busy;
 		req->rq_flags |= RQF_DONTPREP;

This patch looks useful to me since it probably realizes a (small) performance
improvement. I think this patch does not depend on any of the previous patches
in this series. Is that correct?

Yes, it is.

Thanks,
Ming