linux-kernel - [PATCH 1/2] loop: use blk_rq_nr_phys_segments() instead of iterating bvecs

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Message-ID: <20251108230101.4187106-2-csander@purestorage.com>
Date: Sat,  8 Nov 2025 16:01:00 -0700
From: Caleb Sander Mateos <csander@...estorage.com>
To: Jens Axboe <axboe@...nel.dk>,
	Damien Le Moal <dlemoal@...nel.org>,
	Christoph Hellwig <hch@....de>
Cc: linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Caleb Sander Mateos <csander@...estorage.com>
Subject: [PATCH 1/2] loop: use blk_rq_nr_phys_segments() instead of iterating bvecs

The number of bvecs can be obtained directly from struct request's
nr_phys_segments field via blk_rq_nr_phys_segments(), so use that
instead of iterating over the bvecs an extra time.

Signed-off-by: Caleb Sander Mateos <csander@...estorage.com>
---
 drivers/block/loop.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 13ce229d450c..8096478fad45 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -346,16 +346,13 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
 	struct request *rq = blk_mq_rq_from_pdu(cmd);
 	struct bio *bio = rq->bio;
 	struct file *file = lo->lo_backing_file;
 	struct bio_vec tmp;
 	unsigned int offset;
-	int nr_bvec = 0;
+	unsigned short nr_bvec = blk_rq_nr_phys_segments(rq);
 	int ret;
 
-	rq_for_each_bvec(tmp, rq, rq_iter)
-		nr_bvec++;
-
 	if (rq->bio != rq->biotail) {
 
 		bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
 				     GFP_NOIO);
 		if (!bvec)
-- 
2.45.2