From 87213b0d847cd300285b5545598e0548baeb5208 Mon Sep 17 00:00:00 2001 From: Caleb Sander Mateos Date: Mon, 1 Dec 2025 14:41:44 -0700 Subject: [PATCH] ublk: allow non-blocking ctrl cmds in IO_URING_F_NONBLOCK issue Handling most of the ublksrv_ctrl_cmd opcodes require locking a mutex, so ublk_ctrl_uring_cmd() bails out with EAGAIN when called with the IO_URING_F_NONBLOCK issue flag. However, several opcodes can be handled without blocking: - UBLK_CMD_GET_QUEUE_AFFINITY - UBLK_CMD_GET_DEV_INFO - UBLK_CMD_GET_DEV_INFO2 - UBLK_U_CMD_GET_FEATURES Handle these opcodes synchronously instead of returning EAGAIN so io_uring doesn't need to issue the command via the worker thread pool. Signed-off-by: Caleb Sander Mateos Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- drivers/block/ublk_drv.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 2c715df63f23f..3ecaafacfd203 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -3673,6 +3673,19 @@ exit: return ret; } +static bool ublk_ctrl_uring_cmd_may_sleep(u32 cmd_op) +{ + switch (_IOC_NR(cmd_op)) { + case UBLK_CMD_GET_QUEUE_AFFINITY: + case UBLK_CMD_GET_DEV_INFO: + case UBLK_CMD_GET_DEV_INFO2: + case _IOC_NR(UBLK_U_CMD_GET_FEATURES): + return false; + default: + return true; + } +} + static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) { @@ -3681,7 +3694,8 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, u32 cmd_op = cmd->cmd_op; int ret = -EINVAL; - if (issue_flags & IO_URING_F_NONBLOCK) + if (ublk_ctrl_uring_cmd_may_sleep(cmd_op) && + issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ublk_ctrl_cmd_dump(cmd); -- 2.47.3