[PATCH] Missing bio_put following submit_bio_wait

[Shaun Tancheff]

submit_bio_wait() gives the caller an opportunity to examine
struct bio and so expects the caller to issue the put_bio()

This fixes a memory leak reported by a few people in 4.7-rc2
kmemleak report after 9082e87bfbf8 ("block: remove struct bio_batch")

Signed-off-by: Shaun Tancheff <shaun.tanch...@seagate.com>
Tested-by: Catalin Marinas <catalin.mari...@arm.com>
Tested-by: Larry fin...@lwfinger.net
Tested-by: David Drysdale <drysd...@google.com>
---
 block/blk-lib.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 23d7f30..9e29dc3 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -113,6 +113,7 @@ int blkdev_issue_discard(struct block_device *bdev, 
sector_t sector,
                ret = submit_bio_wait(type, bio);
                if (ret == -EOPNOTSUPP)
                        ret = 0;
+               bio_put(bio);
        }
        blk_finish_plug(&plug);
 
@@ -165,8 +166,10 @@ int blkdev_issue_write_same(struct block_device *bdev, 
sector_t sector,
                }
        }
 
-       if (bio)
+       if (bio) {
                ret = submit_bio_wait(REQ_WRITE | REQ_WRITE_SAME, bio);
+               bio_put(bio);
+       }
        return ret != -EOPNOTSUPP ? ret : 0;
 }
 EXPORT_SYMBOL(blkdev_issue_write_same);
@@ -206,8 +209,11 @@ static int __blkdev_issue_zeroout(struct block_device 
*bdev, sector_t sector,
                }
        }
 
-       if (bio)
-               return submit_bio_wait(WRITE, bio);
+       if (bio) {
+               ret = submit_bio_wait(WRITE, bio);
+               bio_put(bio);
+               return ret;
+       }
        return 0;
 }
 
-- 
2.8.1