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Date:   Thu, 25 Mar 2021 21:26:05 +0000
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Subject: [PATCH v2 4/8] block: introduce bio_required_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

This function returns the required alignment for the number of sectors in
a bio. In particular, the number of sectors passed to bio_split() must be
aligned to this value.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 block/blk.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/block/blk.h b/block/blk.h
index 3b53e44b967e..5ef207a6d34c 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -261,6 +261,18 @@ static inline unsigned int bio_allowed_max_sectors(struct request_queue *q)
 	return round_down(UINT_MAX, queue_logical_block_size(q)) >> 9;
 }
 
+/*
+ * The required sector alignment for a bio. The number of sectors in any bio
+ * that's constructed/split must be aligned to this value.
+ */
+static inline unsigned int bio_required_sector_alignment(struct bio *bio)
+{
+	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
+
+	return max(queue_logical_block_size(q) >> SECTOR_SHIFT,
+		   blk_crypto_bio_sectors_alignment(bio));
+}
+
 /*
  * The max bio size which is aligned to q->limits.discard_granularity. This
  * is a hint to split large discard bio in generic block layer, then if device
-- 
2.31.0.291.g576ba9dcdaf-goog