block: make bio_crypt_clone() able to fail

bio_crypt_clone() assumes its gfp_mask argument always includes
__GFP_DIRECT_RECLAIM, so that the mempool_alloc() will always succeed.

However, bio_crypt_clone() might be called with GFP_ATOMIC via
setup_clone() in drivers/md/dm-rq.c, or with GFP_NOWAIT via
kcryptd_io_read() in drivers/md/dm-crypt.c.

Neither case is currently reachable with a bio that actually has an
encryption context.  However, it's fragile to rely on this.  Just make
bio_crypt_clone() able to fail, analogous to bio_integrity_clone().

Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Satya Tangirala <satyat@google.com>
Cc: Satya Tangirala <satyat@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Eric Biggers 2020-09-15 20:53:13 -07:00 committed by Jens Axboe
parent 10ed16662d
commit 07560151db
5 changed files with 42 additions and 29 deletions

View File

@ -713,20 +713,18 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
__bio_clone_fast(b, bio);
bio_crypt_clone(b, bio, gfp_mask);
if (bio_crypt_clone(b, bio, gfp_mask) < 0)
goto err_put;
if (bio_integrity(bio)) {
int ret;
ret = bio_integrity_clone(b, bio, gfp_mask);
if (ret < 0) {
bio_put(b);
return NULL;
}
}
if (bio_integrity(bio) &&
bio_integrity_clone(b, bio, gfp_mask) < 0)
goto err_put;
return b;
err_put:
bio_put(b);
return NULL;
}
EXPORT_SYMBOL(bio_clone_fast);

View File

@ -95,10 +95,13 @@ void __bio_crypt_free_ctx(struct bio *bio)
bio->bi_crypt_context = NULL;
}
void __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
{
dst->bi_crypt_context = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
if (!dst->bi_crypt_context)
return -ENOMEM;
*dst->bi_crypt_context = *src->bi_crypt_context;
return 0;
}
EXPORT_SYMBOL_GPL(__bio_crypt_clone);

View File

@ -267,22 +267,21 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
break;
}
bio_crypt_clone(bio, bio_src, gfp_mask);
if (bio_crypt_clone(bio, bio_src, gfp_mask) < 0)
goto err_put;
if (bio_integrity(bio_src)) {
int ret;
ret = bio_integrity_clone(bio, bio_src, gfp_mask);
if (ret < 0) {
bio_put(bio);
return NULL;
}
}
if (bio_integrity(bio_src) &&
bio_integrity_clone(bio, bio_src, gfp_mask) < 0)
goto err_put;
bio_clone_blkg_association(bio, bio_src);
blkcg_bio_issue_init(bio);
return bio;
err_put:
bio_put(bio);
return NULL;
}
static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,

View File

@ -1326,14 +1326,15 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned len)
{
struct bio *clone = &tio->clone;
int r;
__bio_clone_fast(clone, bio);
bio_crypt_clone(clone, bio, GFP_NOIO);
r = bio_crypt_clone(clone, bio, GFP_NOIO);
if (r < 0)
return r;
if (bio_integrity(bio)) {
int r;
if (unlikely(!dm_target_has_integrity(tio->ti->type) &&
!dm_target_passes_integrity(tio->ti->type))) {
DMWARN("%s: the target %s doesn't support integrity data.",

View File

@ -112,12 +112,24 @@ static inline bool bio_has_crypt_ctx(struct bio *bio)
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
void __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
static inline void bio_crypt_clone(struct bio *dst, struct bio *src,
gfp_t gfp_mask)
int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
/**
* bio_crypt_clone - clone bio encryption context
* @dst: destination bio
* @src: source bio
* @gfp_mask: memory allocation flags
*
* If @src has an encryption context, clone it to @dst.
*
* Return: 0 on success, -ENOMEM if out of memory. -ENOMEM is only possible if
* @gfp_mask doesn't include %__GFP_DIRECT_RECLAIM.
*/
static inline int bio_crypt_clone(struct bio *dst, struct bio *src,
gfp_t gfp_mask)
{
if (bio_has_crypt_ctx(src))
__bio_crypt_clone(dst, src, gfp_mask);
return __bio_crypt_clone(dst, src, gfp_mask);
return 0;
}
#endif /* __LINUX_BLK_CRYPTO_H */