dm: push use of on-stack flush_bio down to __send_empty_flush()

Eliminates duplicate code, no functional change.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm.c

@@ -1426,6 +1426,17 @@ static int __send_empty_flush(struct clone_info *ci)
 {
 	unsigned target_nr = 0;
 	struct dm_target *ti;
+	struct bio flush_bio;
+
+	/*
+	 * Use an on-stack bio for this, it's safe since we don't
+	 * need to reference it after submit. It's just used as
+	 * the basis for the clone(s).
+	 */
+	bio_init(&flush_bio, NULL, 0);
+	flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
+	ci->bio = &flush_bio;
+	ci->sector_count = 0;
 
 	/*
 	 * Empty flush uses a statically initialized bio, as the base for
@@ -1439,6 +1450,8 @@ static int __send_empty_flush(struct clone_info *ci)
 	BUG_ON(bio_has_data(ci->bio));
 	while ((ti = dm_table_get_target(ci->map, target_nr++)))
 		__send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
+
+	bio_uninit(ci->bio);
 	return 0;
 }
 
@@ -1615,19 +1628,7 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
 	init_clone_info(&ci, md, map, bio);
 
 	if (bio->bi_opf & REQ_PREFLUSH) {
-		struct bio flush_bio;
-
-		/*
-		 * Use an on-stack bio for this, it's safe since we don't
-		 * need to reference it after submit. It's just used as
-		 * the basis for the clone(s).
-		 */
-		bio_init(&flush_bio, NULL, 0);
-		flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
-		ci.bio = &flush_bio;
-		ci.sector_count = 0;
 		error = __send_empty_flush(&ci);
-		bio_uninit(ci.bio);
 		/* dec_pending submits any data associated with flush */
 	} else if (op_is_zone_mgmt(bio_op(bio))) {
 		ci.bio = bio;
@@ -1690,19 +1691,7 @@ static blk_qc_t __process_bio(struct mapped_device *md, struct dm_table *map,
 	init_clone_info(&ci, md, map, bio);
 
 	if (bio->bi_opf & REQ_PREFLUSH) {
-		struct bio flush_bio;
-
-		/*
-		 * Use an on-stack bio for this, it's safe since we don't
-		 * need to reference it after submit. It's just used as
-		 * the basis for the clone(s).
-		 */
-		bio_init(&flush_bio, NULL, 0);
-		flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
-		ci.bio = &flush_bio;
-		ci.sector_count = 0;
 		error = __send_empty_flush(&ci);
-		bio_uninit(ci.bio);
 		/* dec_pending submits any data associated with flush */
 	} else {
 		struct dm_target_io *tio;