dm: tidy bio_io_error usage

Use bio_io_error() in only two places and tidy the code,
preparing for later patches.

There is no functional change in this patch.

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

1 files changed, 18 insertions, 19 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7cb61ab887a..41c9549b32a 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -751,15 +751,13 @@ static void __clone_and_map(struct clone_info *ci)
 /*
  * Split the bio into several clones.
  */
-static void __split_bio(struct mapped_device *md, struct bio *bio)
+static int __split_bio(struct mapped_device *md, struct bio *bio)
 {
         struct clone_info ci;
 
         ci.map = dm_get_table(md);
-        if (!ci.map) {
-                bio_io_error(bio);
-                return;
-        }
+        if (unlikely(!ci.map))
+                return -EIO;
 
         ci.md = md;
         ci.bio = bio;
@@ -779,6 +777,8 @@ static void __split_bio(struct mapped_device *md, struct bio *bio)
         /* drop the extra reference count */
         dec_pending(ci.io, 0);
         dm_table_put(ci.map);
+
+        return 0;
 }
 /*-----------------------------------------------------------------
  * CRUD END
@@ -790,7 +790,7 @@ static void __split_bio(struct mapped_device *md, struct bio *bio)
  */
 static int dm_request(struct request_queue *q, struct bio *bio)
 {
-        int r;
+        int r = -EIO;
         int rw = bio_data_dir(bio);
         struct mapped_device *md = q->queuedata;
 
@@ -815,18 +815,11 @@ static int dm_request(struct request_queue *q, struct bio *bio)
         while (test_bit(DMF_BLOCK_IO, &md->flags)) {
                 up_read(&md->io_lock);
 
-                if (bio_rw(bio) == READA) {
-                        bio_io_error(bio);
-                        return 0;
-                }
-
-                r = queue_io(md, bio);
-                if (r < 0) {
-                        bio_io_error(bio);
-                        return 0;
+                if (bio_rw(bio) != READA)
+                        r = queue_io(md, bio);
 
-                } else if (r == 0)
-                        return 0;       /* deferred successfully */
+                if (r <= 0)
+                        goto out_req;
 
                 /*
                  * We're in a while loop, because someone could suspend
@@ -835,8 +828,13 @@ static int dm_request(struct request_queue *q, struct bio *bio)
                 down_read(&md->io_lock);
         }
 
-        __split_bio(md, bio);
+        r = __split_bio(md, bio);
         up_read(&md->io_lock);
+
+out_req:
+        if (r < 0)
+                bio_io_error(bio);
+
         return 0;
 }
 
@@ -1235,7 +1233,8 @@ static void __flush_deferred_io(struct mapped_device *md, struct bio *c)
         while (c) {
                 n = c->bi_next;
                 c->bi_next = NULL;
-                __split_bio(md, c);
+                if (__split_bio(md, c))
+                        bio_io_error(c);
                 c = n;
         }
 }