[PATCH 16/18] scsi-mq: Make behavior scsi_mq_prep_fn() closer to that of scsi_prep_fn()

Bart Van Assche
2017-05-19T18:30:25Z

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 <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/scsi_lib.c | 12 ------------
1 file changed, 12 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 791bae192bfb..e0c4481cb943 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1861,27 +1861,15 @@ 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);
-
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;
--
2.12.2