linux-kernel - [PATCH 05/17] ublk: don't dereference ublk_queue in ublk_ch_uring_cmd

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Message-ID: <20250918014953.297897-6-csander@purestorage.com>
Date: Wed, 17 Sep 2025 19:49:41 -0600
From: Caleb Sander Mateos <csander@...estorage.com>
To: Ming Lei <ming.lei@...hat.com>,
	Jens Axboe <axboe@...nel.dk>
Cc: linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Caleb Sander Mateos <csander@...estorage.com>
Subject: [PATCH 05/17] ublk: don't dereference ublk_queue in ublk_ch_uring_cmd_local()

For ublk servers with many ublk queues, accessing the ublk_queue to
handle a ublk command is a frequent cache miss. Get the queue depth from
the ublk_device instead, which is accessed just before.

Signed-off-by: Caleb Sander Mateos <csander@...estorage.com>
---
 drivers/block/ublk_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 04b8613ce623..58f688eac742 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -2331,11 +2331,11 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd,
 	if (q_id >= ub->dev_info.nr_hw_queues)
 		goto out;
 
 	ubq = ublk_get_queue(ub, q_id);
 
-	if (tag >= ubq->q_depth)
+	if (tag >= ub->dev_info.queue_depth)
 		goto out;
 
 	io = &ubq->ios[tag];
 	/* UBLK_IO_FETCH_REQ can be handled on any task, which sets io->task */
 	if (unlikely(_IOC_NR(cmd_op) == UBLK_IO_FETCH_REQ)) {
-- 
2.45.2