[PATCH v2 08/12] Introduce scsi_mq_sgl_size()

[Bart Van Assche]

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

Signed-off-by: Bart Van Assche <bart.vanass...@sandisk.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Hannes Reinecke <h...@suse.com>
Cc: Johannes Thumshirn <jthumsh...@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