scsi: Introduce scsi_mq_sgl_size()

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>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1470c93..c2a9601 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1859,6 +1859,13 @@ 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);
@@ -1893,10 +1900,7 @@ 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 =
@@ -2202,12 +2206,9 @@ 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;