block: Use DECLARE_COMPLETION_ONSTACK() in submit_bio_wait()

Simplify the code by getting rid of the submit_bio_ret structure.

(This also helps address a lockdep false positive.)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: amir73il@gmail.com
Cc: axboe@kernel.dk
Cc: darrick.wong@oracle.com
Cc: david@fromorbit.com
Cc: hch@infradead.org
Cc: idryomov@gmail.com
Cc: johan@kernel.org
Cc: johannes.berg@intel.com
Cc: kernel-team@lge.com
Cc: linux-block@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: oleg@redhat.com
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1508921765-15396-2-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/block/bio.c b/block/bio.c
index 101c2a9b548150cd3f7bb5b28a460ef82c9e4a75..5e901bfc0576a6bcc55031f0fec5e7730a725acd 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -917,17 +917,9 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 }
 EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
 
-struct submit_bio_ret {
-       struct completion event;
-       int error;
-};
-
 static void submit_bio_wait_endio(struct bio *bio)
 {
-       struct submit_bio_ret *ret = bio->bi_private;
-
-       ret->error = blk_status_to_errno(bio->bi_status);
-       complete(&ret->event);
+       complete(bio->bi_private);
 }
 
 /**
@@ -943,16 +935,15 @@ static void submit_bio_wait_endio(struct bio *bio)
  */
 int submit_bio_wait(struct bio *bio)
 {
-       struct submit_bio_ret ret;
+       DECLARE_COMPLETION_ONSTACK(done);
 
-       init_completion(&ret.event);
-       bio->bi_private = &ret;
+       bio->bi_private = &done;
        bio->bi_end_io = submit_bio_wait_endio;
        bio->bi_opf |= REQ_SYNC;
        submit_bio(bio);
-       wait_for_completion_io(&ret.event);
+       wait_for_completion_io(&done);
 
-       return ret.error;
+       return blk_status_to_errno(bio->bi_status);
 }
 EXPORT_SYMBOL(submit_bio_wait);