Commit 93f221ae authored by Eric Biggers's avatar Eric Biggers Committed by Jens Axboe
Browse files

block: make blk_crypto_rq_bio_prep() able to fail 



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

However, blk_crypto_rq_bio_prep() might be called with GFP_ATOMIC via
setup_clone() in drivers/md/dm-rq.c.

This case isn't currently reachable with a bio that actually has an
encryption context.  However, it's fragile to rely on this.  Just make
blk_crypto_rq_bio_prep() able to fail.

Suggested-by: default avatarSatya Tangirala <satyat@google.com>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Reviewed-by: default avatarMike Snitzer <snitzer@redhat.com>
Reviewed-by: default avatarSatya Tangirala <satyat@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 07560151

block/blk-core.c

+5 −3
Original line number Diff line number Diff line
@@ -1617,9 +1617,11 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 
		if (rq->bio) {

			rq->biotail->bi_next = bio;

			rq->biotail = bio;

		} else

		} else {

			rq->bio = rq->biotail = bio;

		}

		bio = NULL;

	}



	/* Copy attributes of the original request to the clone request. */

	rq->__sector = blk_rq_pos(rq_src);
@@ -1631,8 +1633,8 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 
	rq->nr_phys_segments = rq_src->nr_phys_segments;

	rq->ioprio = rq_src->ioprio;



	if (rq->bio)

		blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask);

	if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)

		goto free_and_out;



	return 0;

block/blk-crypto-internal.h

+16 −5
Original line number Diff line number Diff line
@@ -142,13 +142,24 @@ static inline void blk_crypto_free_request(struct request *rq) 
		__blk_crypto_free_request(rq);

}



void __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,

int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,

			     gfp_t gfp_mask);

static inline void blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,

/**

 * blk_crypto_rq_bio_prep - Prepare a request's crypt_ctx when its first bio

 *			    is inserted

 * @rq: The request to prepare

 * @bio: The first bio being inserted into the request

 * @gfp_mask: Memory allocation flags

 *

 * 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 blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,

					 gfp_t gfp_mask)

{

	if (bio_has_crypt_ctx(bio))

		__blk_crypto_rq_bio_prep(rq, bio, gfp_mask);

		return __blk_crypto_rq_bio_prep(rq, bio, gfp_mask);

	return 0;

}



/**

block/blk-crypto.c

+7 −11
Original line number Diff line number Diff line
@@ -283,20 +283,16 @@ fail: 
	return false;

}



/**

 * __blk_crypto_rq_bio_prep - Prepare a request's crypt_ctx when its first bio

 *			      is inserted

 *

 * @rq: The request to prepare

 * @bio: The first bio being inserted into the request

 * @gfp_mask: gfp mask

 */

void __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,

int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,

			     gfp_t gfp_mask)

{

	if (!rq->crypt_ctx)

	if (!rq->crypt_ctx) {

		rq->crypt_ctx = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);

		if (!rq->crypt_ctx)

			return -ENOMEM;

	}

	*rq->crypt_ctx = *bio->bi_crypt_context;

	return 0;

}



/**

block/blk-mq.c

+6 −1
Original line number Diff line number Diff line
@@ -1940,13 +1940,18 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) 
static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,

		unsigned int nr_segs)

{

	int err;



	if (bio->bi_opf & REQ_RAHEAD)

		rq->cmd_flags |= REQ_FAILFAST_MASK;



	rq->__sector = bio->bi_iter.bi_sector;

	rq->write_hint = bio->bi_write_hint;

	blk_rq_bio_prep(rq, bio, nr_segs);

	blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);



	/* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */

	err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);

	WARN_ON_ONCE(err);



	blk_account_io_start(rq);

}

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