linux-kernel - [PATCH v8 2/8] block: blk-crypto: relax alignment requirements for bvecs in bios

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Date:   Thu, 21 Jan 2021 23:03:30 +0000
From:   Satya Tangirala <satyat@...gle.com>
To:     "Theodore Y . Ts'o" <tytso@....edu>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Eric Biggers <ebiggers@...nel.org>, Chao Yu <chao@...nel.org>,
        Jens Axboe <axboe@...nel.dk>,
        "Darrick J . Wong" <darrick.wong@...cle.com>
Cc:     linux-kernel@...r.kernel.org, linux-fscrypt@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, linux-xfs@...r.kernel.org,
        linux-block@...r.kernel.org, linux-ext4@...r.kernel.org,
        Satya Tangirala <satyat@...gle.com>,
        Eric Biggers <ebiggers@...gle.com>
Subject: [PATCH v8 2/8] block: blk-crypto: relax alignment requirements for
 bvecs in bios

blk-crypto only accepted bios whose bvecs' offsets and lengths were aligned
to the crypto data unit size, since blk-crypto-fallback required that to
work correctly.

Now that the blk-crypto-fallback has been updated to work without that
assumption, we relax the alignment requirement - blk-crypto now only needs
the total size of the bio to be aligned to the crypto data unit size.

Co-developed-by: Eric Biggers <ebiggers@...gle.com>
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
Signed-off-by: Satya Tangirala <satyat@...gle.com>
---
 block/blk-crypto.c | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index 5da43f0973b4..fcee0038f7e0 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -200,22 +200,6 @@ bool bio_crypt_ctx_mergeable(struct bio_crypt_ctx *bc1, unsigned int bc1_bytes,
 	return !bc1 || bio_crypt_dun_is_contiguous(bc1, bc1_bytes, bc2->bc_dun);
 }
 
-/* Check that all I/O segments are data unit aligned. */
-static bool bio_crypt_check_alignment(struct bio *bio)
-{
-	const unsigned int data_unit_size =
-		bio->bi_crypt_context->bc_key->crypto_cfg.data_unit_size;
-	struct bvec_iter iter;
-	struct bio_vec bv;
-
-	bio_for_each_segment(bv, bio, iter) {
-		if (!IS_ALIGNED(bv.bv_len | bv.bv_offset, data_unit_size))
-			return false;
-	}
-
-	return true;
-}
-
 blk_status_t __blk_crypto_init_request(struct request *rq)
 {
 	return blk_ksm_get_slot_for_key(rq->q->ksm, rq->crypt_ctx->bc_key,
@@ -271,7 +255,8 @@ bool __blk_crypto_bio_prep(struct bio **bio_ptr)
 		goto fail;
 	}
 
-	if (!bio_crypt_check_alignment(bio)) {
+	if (!IS_ALIGNED(bio->bi_iter.bi_size,
+			bc_key->crypto_cfg.data_unit_size)) {
 		bio->bi_status = BLK_STS_IOERR;
 		goto fail;
 	}
-- 
2.30.0.280.ga3ce27912f-goog