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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 <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
pull/1354/merge
Caleb Sander Mateos 2025-12-01 14:41:44 -07:00 committed by Jens Axboe
parent 0f45353dd4
commit 87213b0d84
1 changed files with 15 additions and 1 deletions
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16
drivers/block/ublk_drv.c
View File

@ -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);