scsi: blk-mq: Add callbacks for storing & retrieving budget token

Since SCSI is the only driver which requires dispatch budget move the token
from struct request to struct scsi_cmnd.

Link: https://lore.kernel.org/r/20210122023317.687987-8-ming.lei@redhat.com
Cc: Omar Sandoval <osandov@fb.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumanesh Samanta <sumanesh.samanta@broadcom.com>
Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Tested-by: Sumanesh Samanta <sumanesh.samanta@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
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 7d52a11..02da34a 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1642,6 +1642,20 @@ static bool scsi_mq_get_budget(struct request_queue *q)
        return false;
 }
 
+static void scsi_mq_set_rq_budget_token(struct request *req, int token)
+{
+       struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+
+       cmd->budget_token = token;
+}
+
+static int scsi_mq_get_rq_budget_token(struct request *req)
+{
+       struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+
+       return cmd->budget_token;
+}
+
 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
                         const struct blk_mq_queue_data *bd)
 {
@@ -1856,6 +1870,8 @@ static const struct blk_mq_ops scsi_mq_ops_no_commit = {
        .cleanup_rq     = scsi_cleanup_rq,
        .busy           = scsi_mq_lld_busy,
        .map_queues     = scsi_map_queues,
+       .set_rq_budget_token = scsi_mq_set_rq_budget_token,
+       .get_rq_budget_token = scsi_mq_get_rq_budget_token,
 };
 
 
@@ -1884,6 +1900,8 @@ static const struct blk_mq_ops scsi_mq_ops = {
        .cleanup_rq     = scsi_cleanup_rq,
        .busy           = scsi_mq_lld_busy,
        .map_queues     = scsi_map_queues,
+       .set_rq_budget_token = scsi_mq_set_rq_budget_token,
+       .get_rq_budget_token = scsi_mq_get_rq_budget_token,
 };
 
 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 2c473c9..5fae401 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -313,6 +313,15 @@ struct blk_mq_ops {
         */
        void (*put_budget)(struct request_queue *);
 
+       /*
+        * @set_rq_budget_toekn: store rq's budget token
+        */
+       void (*set_rq_budget_token)(struct request *, int);
+       /*
+        * @get_rq_budget_toekn: retrieve rq's budget token
+        */
+       int (*get_rq_budget_token)(struct request *);
+
        /**
         * @timeout: Called on request timeout.
         */

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index ace15b5..0cf2b5c 100644 (file)
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -75,6 +75,8 @@ struct scsi_cmnd {
 
        int eh_eflags;          /* Used by error handlr */
 
+       int budget_token;
+
        /*
         * This is set to jiffies as it was when the command was first
         * allocated.  It is used to time how long the command has