[PATCH -next 3/8] md/raid1-10: factor out a helper to add bio to plug

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

The code in raid1 and raid10 is identical, prepare to limit the number
of pluged bios.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 drivers/md/raid1-10.h | 16 ++++++++++++++++
 drivers/md/raid1.c    | 12 +-----------
 drivers/md/raid10.c   | 11 +----------
 3 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/drivers/md/raid1-10.h b/drivers/md/raid1-10.h
index 04beef35142d..664646a3591a 100644
--- a/drivers/md/raid1-10.h
+++ b/drivers/md/raid1-10.h
@@ -112,4 +112,20 @@ static inline void md_bio_reset_resync_pages(struct bio *bio,
 		size -= len;
 	} while (idx++ < RESYNC_PAGES && size > 0);
 }
+
+static inline bool md_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
+				      blk_plug_cb_fn unplug)
+{
+	struct raid1_plug_cb *plug = NULL;
+	struct blk_plug_cb *cb = blk_check_plugged(unplug, mddev,
+						   sizeof(*plug));
+
+	if (!cb)
+		return false;
+
+	plug = container_of(cb, struct raid1_plug_cb, cb);
+	bio_list_add(&plug->pending, bio);
+
+	return true;
+}
 #endif
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 84724b9b20b8..44c8d113621f 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1341,8 +1341,6 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 	struct bitmap *bitmap = mddev->bitmap;
 	unsigned long flags;
 	struct md_rdev *blocked_rdev;
-	struct blk_plug_cb *cb;
-	struct raid1_plug_cb *plug = NULL;
 	int first_clone;
 	int max_sectors;
 	bool write_behind = false;
@@ -1571,15 +1569,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 					      r1_bio->sector);
 		/* flush_pending_writes() needs access to the rdev so...*/
 		mbio->bi_bdev = (void *)rdev;
-
-		cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
-		if (cb)
-			plug = container_of(cb, struct raid1_plug_cb, cb);
-		else
-			plug = NULL;
-		if (plug) {
-			bio_list_add(&plug->pending, mbio);
-		} else {
+		if (!md_add_bio_to_plug(mddev, mbio, raid1_unplug)) {
 			spin_lock_irqsave(&conf->device_lock, flags);
 			bio_list_add(&conf->pending_bio_list, mbio);
 			spin_unlock_irqrestore(&conf->device_lock, flags);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 50d56b6af42f..d67c5672933c 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1279,8 +1279,6 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
 	const blk_opf_t do_sync = bio->bi_opf & REQ_SYNC;
 	const blk_opf_t do_fua = bio->bi_opf & REQ_FUA;
 	unsigned long flags;
-	struct blk_plug_cb *cb;
-	struct raid1_plug_cb *plug = NULL;
 	struct r10conf *conf = mddev->private;
 	struct md_rdev *rdev;
 	int devnum = r10_bio->devs[n_copy].devnum;
@@ -1320,14 +1318,7 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
 
 	atomic_inc(&r10_bio->remaining);
 
-	cb = blk_check_plugged(raid10_unplug, mddev, sizeof(*plug));
-	if (cb)
-		plug = container_of(cb, struct raid1_plug_cb, cb);
-	else
-		plug = NULL;
-	if (plug) {
-		bio_list_add(&plug->pending, mbio);
-	} else {
+	if (!md_add_bio_to_plug(mddev, mbio, raid10_unplug)) {
 		spin_lock_irqsave(&conf->device_lock, flags);
 		bio_list_add(&conf->pending_bio_list, mbio);
 		spin_unlock_irqrestore(&conf->device_lock, flags);
-- 
2.39.2