[PATCH v3 09/12] Make scsi_mq_prep_fn() call scsi_init_command()

Bart Van Assche
2017-06-02T21:22:20Z

This patch reduces code duplication. There are two functional changes
in this patch:
- It causes scsi_mq_prep_fn() to clear driver-private
command data, just like the already upstream commit 1bad6c4a57ef
("scsi: zero per-cmd private driver data for each MQ I/O").
- The initialization of .prot_sdb is moved from scsi_mq_prep_fn()
into scsi_init_request().

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
---
drivers/scsi/scsi_lib.c | 25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6b4fb48033fb..ef4e33319407 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1870,36 +1870,21 @@ 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;
- unsigned int unchecked_isa_dma = cmd->flags & SCMD_UNCHECKED_ISA_DMA;
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));
+ scsi_init_command(sdev, cmd);

req->special = cmd;

cmd->request = req;
- cmd->device = sdev;
- cmd->sense_buffer = sense_buf;
- cmd->flags = unchecked_isa_dma;

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;
cmd->sdb.table.sgl = sg;

if (scsi_host_get_prot(shost)) {
- cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost);
memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));

cmd->prot_sdb->table.sgl =
@@ -2025,6 +2010,7 @@ static int scsi_init_request(struct blk_mq_tag_set *set, struct request *rq,
struct Scsi_Host *shost = set->driver_data;
const bool unchecked_isa_dma = shost->unchecked_isa_dma;
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+ struct scatterlist *sg;

if (unchecked_isa_dma)
cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
@@ -2033,6 +2019,13 @@ static int scsi_init_request(struct blk_mq_tag_set *set, struct request *rq,
if (!cmd->sense_buffer)
return -ENOMEM;
cmd->req.sense = cmd->sense_buffer;
+
+ if (scsi_host_get_prot(shost)) {
+ sg = (void *)cmd + sizeof(struct scsi_cmnd) +
+ shost->hostt->cmd_size;
+ cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost);
+ }
+
return 0;
}

--
2.12.2