From: Alasdair G Kergon <agk@redhat.com>
Date: Wed, 8 Apr 2009 23:27:14 +0000 (+0100)
Subject: dm: simplify dm_request loop
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=54d9a1b4513b96cbd835ca6866c6a604d194b2ae;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

dm: simplify dm_request loop

Refactor the code in dm_request().

Require the new DMF_BLOCK_FOR_SUSPEND flag on readahead bios we will
discard so we don't drop such bios while processing a barrier.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7cac7220937f..bb97ec8d6644 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -929,7 +929,6 @@ out:
  */
 static int dm_request(struct request_queue *q, struct bio *bio)
 {
-	int r = -EIO;
 	int rw = bio_data_dir(bio);
 	struct mapped_device *md = q->queuedata;
 	int cpu;
@@ -957,11 +956,14 @@ static int dm_request(struct request_queue *q, struct bio *bio)
 	while (test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) {
 		up_read(&md->io_lock);
 
-		if (bio_rw(bio) != READA)
-			r = queue_io(md, bio);
+		if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) &&
+		    bio_rw(bio) == READA) {
+			bio_io_error(bio);
+			return 0;
+		}
 
-		if (r <= 0)
-			goto out_req;
+		if (!queue_io(md, bio))
+			return 0;
 
 		/*
 		 * We're in a while loop, because someone could suspend
@@ -973,12 +975,6 @@ static int dm_request(struct request_queue *q, struct bio *bio)
 	__split_and_process_bio(md, bio);
 	up_read(&md->io_lock);
 	return 0;
-
-out_req:
-	if (r < 0)
-		bio_io_error(bio);
-
-	return 0;
 }
 
 static void dm_unplug_all(struct request_queue *q)