block: fix memleak of bio integrity data

7c20f11680a4 ("bio-integrity: stop abusing bi_end_io") moves
bio_integrity_free from bio_uninit() to bio_integrity_verify_fn()
and bio_endio(). This way looks wrong because bio may be freed
without calling bio_endio(), for example, blk_rq_unprep_clone() is
called from dm_mq_queue_rq() when the underlying queue of dm-mpath
is busy.

So memory leak of bio integrity data is caused by commit 7c20f11680a4.

Fixes this issue by re-adding bio_integrity_free() to bio_uninit().

Fixes: 7c20f11680a4 ("bio-integrity: stop abusing bi_end_io")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by Justin Tee <justin.tee@broadcom.com>

Add commit log, and simplify/fix the original patch wroten by Justin.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/bio.c b/block/bio.c
index b1170ec..9d54aa3 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -233,6 +233,9 @@ struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
 void bio_uninit(struct bio *bio)
 {
 	bio_disassociate_blkg(bio);
+
+	if (bio_integrity(bio))
+		bio_integrity_free(bio);
 }
 EXPORT_SYMBOL(bio_uninit);