block: remove unused REQ_UNPLUG

The request inherits the unplug flag from the bio, but it isn't actually
used. The bio flag stops at __make_request(), which tells it to unplug
after submission. Passing it on to the request doesn't make any sense.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index 3688abf..43fdedc 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1123,8 +1123,6 @@
 
 	if (bio_sync(bio))
 		req->cmd_flags |= REQ_RW_SYNC;
-	if (bio_unplug(bio))
-		req->cmd_flags |= REQ_UNPLUG;
 	if (bio_rw_meta(bio))
 		req->cmd_flags |= REQ_RW_META;
 	if (bio_noidle(bio))
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e036609..ba54c83 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -117,7 +117,6 @@
 	__REQ_RW_META,		/* metadata io request */
 	__REQ_COPY_USER,	/* contains copies of user pages */
 	__REQ_INTEGRITY,	/* integrity metadata has been remapped */
-	__REQ_UNPLUG,		/* unplug queue on submission */
 	__REQ_NOIDLE,		/* Don't anticipate more IO after this one */
 	__REQ_NR_BITS,		/* stops here */
 };
@@ -145,7 +144,6 @@
 #define REQ_RW_META	(1 << __REQ_RW_META)
 #define REQ_COPY_USER	(1 << __REQ_COPY_USER)
 #define REQ_INTEGRITY	(1 << __REQ_INTEGRITY)
-#define REQ_UNPLUG	(1 << __REQ_UNPLUG)
 #define REQ_NOIDLE	(1 << __REQ_NOIDLE)
 
 #define BLK_MAX_CDB	16