From: Eric Biggers <ebiggers@xxxxxxxxxx>
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.
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Suggested-by: Satya Tangirala <satyat@xxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
block/blk-core.c | 8 +++++---
block/blk-crypto-internal.h | 21 ++++++++++++++++-----
block/blk-crypto.c | 18 +++++++-----------
block/blk-mq.c | 7 ++++++-
4 files changed, 34 insertions(+), 20 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index ca3f0f00c9435..fbeaa49f6fe2c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1620,8 +1620,10 @@ 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. */
@@ -1634,8 +1636,8 @@ 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;
diff --git a/block/blk-crypto-internal.h b/block/blk-crypto-internal.h
index d2b0f565d83cb..0d36aae538d7b 100644
--- a/block/blk-crypto-internal.h
+++ b/block/blk-crypto-internal.h
@@ -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,
- gfp_t gfp_mask);
-static inline void blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
- gfp_t gfp_mask)
+int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
+ gfp_t gfp_mask);
+/**
+ * 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;
}
/**
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index a3f27a19067c9..bbe7974fd74f0 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -283,20 +283,16 @@ bool __blk_crypto_bio_prep(struct bio **bio_ptr)
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,
- gfp_t gfp_mask)
+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;
}
/**
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e04b759add758..9ec0e7149ae69 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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);
}
--
2.28.0
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