dm mpath: use blk_mq_alloc_request() and blk_mq_free_request() directly

There isn't any need to support both old .request_fn and blk-mq paths
in the blk-mq specific portion of __multipath_map().  Call
blk_mq_alloc_request() directly rather than use blk_get_request().

Similarly, call blk_mq_free_request(), rather than blk_put_request(), in
multipath_release_clone().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 612ec571862de1c6b3c59cb706ca12781ac3c572..798644624663ad57369690461889cb34ff1ca2fe 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -23,6 +23,7 @@
 #include <linux/delay.h>
 #include <scsi/scsi_dh.h>
 #include <linux/atomic.h>
+#include <linux/blk-mq.h>
 
 #define DM_MSG_PREFIX "multipath"
 #define DM_PG_INIT_DELAY_MSECS 2000
@@ -439,14 +440,22 @@ static int __multipath_map(struct dm_target *ti, struct request *clone,
        spin_unlock_irq(&m->lock);
 
        if (clone) {
-               /* Old request-based interface: allocated clone is passed in */
+               /*
+                * Old request-based interface: allocated clone is passed in.
+                * Used by both: .request_fn stacked on .request_fn path(s) and
+                * blk-mq stacked on .request_fn path(s).
+                */
                clone->q = bdev_get_queue(bdev);
                clone->rq_disk = bdev->bd_disk;
                clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
        } else {
-               /* blk-mq request-based interface */
-               *__clone = blk_get_request(bdev_get_queue(bdev),
-                                          rq_data_dir(rq), GFP_ATOMIC);
+               /*
+                * blk-mq request-based interface; used by both:
+                * .request_fn stacked on blk-mq path(s) and
+                * blk-mq stacked on blk-mq path(s).
+                */
+               *__clone = blk_mq_alloc_request(bdev_get_queue(bdev),
+                                               rq_data_dir(rq), BLK_MQ_REQ_NOWAIT);
                if (IS_ERR(*__clone)) {
                        /* ENOMEM, requeue */
                        return r;
@@ -483,7 +492,7 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
 
 static void multipath_release_clone(struct request *clone)
 {
-       blk_put_request(clone);
+       blk_mq_free_request(clone);
 }
 
 /*