block: cleanup bio_endio

Replace the while loop that unecessarily checks for a NULL bio in the fast
path with a simple goto loop.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/bio.c b/block/bio.c
index 67e51ace1b7735af340edb387225e907f59f33f0..e4682ec11fcd111f4938c94286d0ea28426e8013 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1745,26 +1745,25 @@ static inline bool bio_remaining_done(struct bio *bio)
  **/
 void bio_endio(struct bio *bio)
 {
-       while (bio) {
-               if (unlikely(!bio_remaining_done(bio)))
-                       break;
+again:
+       if (unlikely(!bio_remaining_done(bio)))
+               return;
 
-               /*
-                * Need to have a real endio function for chained bios,
-                * otherwise various corner cases will break (like stacking
-                * block devices that save/restore bi_end_io) - however, we want
-                * to avoid unbounded recursion and blowing the stack. Tail call
-                * optimization would handle this, but compiling with frame
-                * pointers also disables gcc's sibling call optimization.
-                */
-               if (bio->bi_end_io == bio_chain_endio) {
-                       bio = __bio_chain_endio(bio);
-               } else {
-                       if (bio->bi_end_io)
-                               bio->bi_end_io(bio);
-                       bio = NULL;
-               }
+       /*
+        * Need to have a real endio function for chained bios, otherwise
+        * various corner cases will break (like stacking block devices that
+        * save/restore bi_end_io) - however, we want to avoid unbounded
+        * recursion and blowing the stack. Tail call optimization would
+        * handle this, but compiling with frame pointers also disables
+        * gcc's sibling call optimization.
+        */
+       if (bio->bi_end_io == bio_chain_endio) {
+               bio = __bio_chain_endio(bio);
+               goto again;
        }
+
+       if (bio->bi_end_io)
+               bio->bi_end_io(bio);
 }
 EXPORT_SYMBOL(bio_endio);