Re: [dm-devel] [PATCH v2 02/14] dm: kill dm_rq_bio_destructor

On Thu, May 24, 2012 at 09:19:12AM +0900, Jun'ichi Nomura wrote:

Hi,

On 05/24/12 09:02, Kent Overstreet wrote:

quoted

@@ -1438,15 +1439,6 @@ void dm_dispatch_request(struct request *rq)
 }
 EXPORT_SYMBOL_GPL(dm_dispatch_request);
 
-static void dm_rq_bio_destructor(struct bio *bio)
-{
-	struct dm_rq_clone_bio_info *info = bio->bi_private;
-	struct mapped_device *md = info->tio->md;
-
-	free_bio_info(info);
-	bio_free(bio, md->bs);
-}
-
 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
 				 void *data)
 {

@@ -1461,7 +1453,6 @@ static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
 	info->tio = tio;
 	bio->bi_end_io = end_clone_bio;
 	bio->bi_private = info;
-	bio->bi_destructor = dm_rq_bio_destructor;

The destructor may also be called from blk_rq_unprep_clone(),
which just puts bio.
So this patch will introduce a memory leak.

Well, keeping around bi_destructor solely for that reason would be
pretty lousy. Can you come up with a better solution?