linux-kernel - [PATCH 09/17] ublk: don't access ublk_queue in ublk_daemon_register_io

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Message-ID: <20250918014953.297897-10-csander@purestorage.com>
Date: Wed, 17 Sep 2025 19:49:45 -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 09/17] ublk: don't access ublk_queue in ublk_daemon_register_io_buf()

For ublk servers with many ublk queues, accessing the ublk_queue in
ublk_daemon_register_io_buf() is a frequent cache miss. Get the flags
from the ublk_device instead, which is accessed earlier in
ublk_ch_uring_cmd_local().

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 751ec62655f8..266b46d40886 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -2167,11 +2167,11 @@ ublk_daemon_register_io_buf(struct io_uring_cmd *cmd,
 	new_registered_buffers = io->task_registered_buffers + 1;
 	if (unlikely(new_registered_buffers >= UBLK_REFCOUNT_INIT))
 		return ublk_register_io_buf(cmd, ub, ubq, io, index,
 					    issue_flags);
 
-	if (!ublk_support_zero_copy(ubq) || !ublk_rq_has_data(req))
+	if (!ublk_dev_support_zero_copy(ub) || !ublk_rq_has_data(req))
 		return -EINVAL;
 
 	ret = io_buffer_register_bvec(cmd, req, ublk_io_release, index,
 				      issue_flags);
 	if (ret)
-- 
2.45.2