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Date:   Fri,  4 Jun 2021 19:59:00 +0000
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Subject: [PATCH v3 10/10] block: add WARN_ON_ONCE() to bio_split() for sector alignment
From:   Satya Tangirala <satyat@google.com>
To:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Jens Axboe <axboe@kernel.dk>, Eric Biggers <ebiggers@google.com>,
        Satya Tangirala <satyat@google.com>
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Precedence: bulk

The number of sectors passed to bio_split() should be aligned to
bio_required_sector_alignment(). All callers (other than bounce.c) have
been updated to ensure this, so add a WARN_ON_ONCE() if the number of
sectors is not aligned. (bounce.c was not updated since it's legacy code -
any device that enables bounce buffering won't declare inline
encryption support, so bounce.c will never see a bio with an encryption
context).

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 block/bio.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/bio.c b/block/bio.c
index 44205dfb6b60..32f75f31bb5c 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1436,6 +1436,7 @@ struct bio *bio_split(struct bio *bio, int sectors,
 
 	BUG_ON(sectors <= 0);
 	BUG_ON(sectors >= bio_sectors(bio));
+	WARN_ON_ONCE(!IS_ALIGNED(sectors, bio_required_sector_alignment(bio)));
 
 	/* Zone append commands cannot be split */
 	if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
-- 
2.32.0.rc1.229.g3e70b5a671-goog