[PATCH v3 08/12] Introduce scsi_mq_sgl_size()

Bart Van Assche
2017-06-02T21:22:19Z

This patch does not change any functionality but makes the next
patch easier to read.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
---
drivers/scsi/scsi_lib.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 2c43b500e9f4..6b4fb48033fb 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1858,6 +1858,13 @@ static inline int prep_to_mq(int ret)
}
}

+/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
+static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost)
+{
+ return min_t(unsigned int, shost->sg_tablesize, SG_CHUNK_SIZE) *
+ sizeof(struct scatterlist);
+}
+
static int scsi_mq_prep_fn(struct request *req)
{
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
@@ -1892,10 +1899,7 @@ static int scsi_mq_prep_fn(struct request *req)
cmd->sdb.table.sgl = sg;

if (scsi_host_get_prot(shost)) {
- cmd->prot_sdb = (void *)sg +
- min_t(unsigned int,
- shost->sg_tablesize, SG_CHUNK_SIZE) *
- sizeof(struct scatterlist);
+ 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 =
@@ -2201,12 +2205,9 @@ struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)

int scsi_mq_setup_tags(struct Scsi_Host *shost)
{
- unsigned int cmd_size, sgl_size, tbl_size;
+ unsigned int cmd_size, sgl_size;

- tbl_size = shost->sg_tablesize;
- if (tbl_size > SG_CHUNK_SIZE)
- tbl_size = SG_CHUNK_SIZE;
- sgl_size = tbl_size * sizeof(struct scatterlist);
+ sgl_size = scsi_mq_sgl_size(shost);
cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
if (scsi_host_get_prot(shost))
cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
--
2.12.2