[RFC PATCH v2 4/8] blk-mq: factor out a dma-buf bio refusal helper

[Mengmeng Zhao <mengmeng.zhao@linux.dev>]

From: Mengmeng Zhao <zhaomengmeng@kylinos.cn>

Move the dma-buf integrity check out of blk_mq_submit_bio() into
bio_dmabuf_should_reject(), so that such checks have one place to grow.

No functional change.

Signed-off-by: Mengmeng Zhao <zhaomengmeng@kylinos.cn>
Signed-off-by: Li Wang <liwang@kylinos.cn>
---
 block/blk-mq.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5ae22d556540..887d5cc5bb5e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3099,6 +3099,20 @@ static bool bio_unaligned(const struct bio *bio, struct request_queue *q)
 	return false;
 }
 
+/*
+ * A dma-buf bio carries a driver-private map instead of pages, so the block
+ * layer cannot generate or verify integrity metadata for it.  Only reject when
+ * it would have to do that itself, not if the submitter attached its own
+ * payload or if generation or verification is turned off for the device.
+ */
+static bool bio_dmabuf_should_reject(struct bio *bio)
+{
+	if (!op_is_dmabuf(bio->bi_opf))
+		return false;
+	return bdev_has_integrity_csum(bio->bi_bdev) &&
+	       (bio_integrity_action(bio) & BI_ACT_CHECK);
+}
+
 /**
  * blk_mq_submit_bio - Create and send a request to block device.
  * @bio: Bio pointer.
@@ -3160,15 +3174,7 @@ void blk_mq_submit_bio(struct bio *bio)
 		goto queue_exit;
 	}
 
-	/*
-	 * The block layer cannot generate or verify PI for a dma-buf bio, as
-	 * that walks the data pages.  Only fail the bio if it needs that, not
-	 * if the submitter attached its own integrity payload or if PI
-	 * generation or verification is turned off for the device.
-	 */
-	if (unlikely(op_is_dmabuf(bio->bi_opf) &&
-		     bdev_has_integrity_csum(bio->bi_bdev) &&
-		     (bio_integrity_action(bio) & BI_ACT_CHECK))) {
+	if (unlikely(bio_dmabuf_should_reject(bio))) {
 		bio_endio_status(bio, BLK_STS_NOTSUPP);
 		goto queue_exit;
 	}
-- 
2.43.0