xen-blkback: fix dispatch_rw_block_io() error path
Commit 7708992 ("xen/blkback: Seperate the bio allocation and the bio
submission") consolidated the pendcnt updates to just a single write,
neglecting the fact that the error path relied on it getting set to 1
up front (such that the decrement in __end_block_io_op() would actually
drop the count to zero, triggering the necessary cleanup actions).
Also remove a misleading and a stale (after said commit) comment.
CC: stable@vger.kernel.org
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index eaccc22..477a17c 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -1001,13 +1001,7 @@
bio->bi_end_io = end_block_io_op;
}
- /*
- * We set it one so that the last submit_bio does not have to call
- * atomic_inc.
- */
atomic_set(&pending_req->pendcnt, nbio);
-
- /* Get a reference count for the disk queue and start sending I/O */
blk_start_plug(&plug);
for (i = 0; i < nbio; i++)
@@ -1035,6 +1029,7 @@
fail_put_bio:
for (i = 0; i < nbio; i++)
bio_put(biolist[i]);
+ atomic_set(&pending_req->pendcnt, 1);
__end_block_io_op(pending_req, -EINVAL);
msleep(1); /* back off a bit */
return -EIO;