Thread (73 messages) 73 messages, 6 authors, 2017-05-24

Re: [PATCH 25/31] scsi-mq: Make behavior scsi_mq_prep_fn() closer to that of scsi_prep_fn()

From: Hannes Reinecke <hare@suse.de>
Date: 2017-05-24 06:12:01
Also in: linux-scsi

On 05/24/2017 02:34 AM, Bart Van Assche wrote:
quoted hunk ↗ jump to hunk
Instead of clearing most of struct scsi_cmnd and reinitializing
it, rely on scsi_initialize_rq() for initialization of struct
scsi_cmnd. This patch fixes a bug, namely that it avoids that
jiffies_at_alloc gets overwritten if a request is requeued.

Signed-off-by: Bart Van Assche <redacted>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/scsi_lib.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 4b24c45fa113..12fd2bb0fe9c 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1861,27 +1861,17 @@ static int scsi_mq_prep_fn(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;
-	unsigned char *sense_buf = cmd->sense_buffer;
 	struct scatterlist *sg;
 
-	/* zero out the cmd, except for the embedded scsi_request */
-	memset((char *)cmd + sizeof(cmd->req), 0,
-		sizeof(*cmd) - sizeof(cmd->req) + shost->hostt->cmd_size);
+	memset(scsi_cmd_priv(cmd), 0, shost->hostt->cmd_size);
 
 	req->special = cmd;
 
 	cmd->request = req;
-	cmd->device = sdev;
-	cmd->sense_buffer = sense_buf;
 
 	cmd->tag = req->tag;
-
 	cmd->prot_op = SCSI_PROT_NORMAL;
 
-	INIT_LIST_HEAD(&cmd->list);
-	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
-	cmd->jiffies_at_alloc = jiffies;
-
 	scsi_add_cmd_to_list(cmd);
 
 	sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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