On Mon, Sep 1, 2025 at 3:03 AM Ming Lei <ming.lei@xxxxxxxxxx> wrote:
>
> Add helper __ublk_fetch() for the coming batch io feature.
>
> Meantime move ublk_config_io_buf() out of __ublk_fetch() because batch
> io has new interface for configuring buffer.
>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> drivers/block/ublk_drv.c | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index e53f623b0efe..f265795a8d57 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -2206,18 +2206,12 @@ static int ublk_check_fetch_buf(const struct ublk_queue *ubq, __u64 buf_addr)
> return 0;
> }
>
> -static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
> - struct ublk_io *io, __u64 buf_addr)
> +static int __ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
> + struct ublk_io *io)
> {
> struct ublk_device *ub = ubq->dev;
> int ret = 0;
>
> - /*
> - * When handling FETCH command for setting up ublk uring queue,
> - * ub->mutex is the innermost lock, and we won't block for handling
> - * FETCH, so it is fine even for IO_URING_F_NONBLOCK.
> - */
> - mutex_lock(&ub->mutex);
> /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
> if (ublk_queue_ready(ubq)) {
> ret = -EBUSY;
> @@ -2233,13 +2227,28 @@ static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
> WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV);
>
> ublk_fill_io_cmd(io, cmd);
> - ret = ublk_config_io_buf(ubq, io, cmd, buf_addr, NULL);
> - if (ret)
> - goto out;
>
> WRITE_ONCE(io->task, get_task_struct(current));
> ublk_mark_io_ready(ub, ubq);
> out:
> + return ret;
If the out: section no longer releases any resources, can we replace
the "goto out" with just "return ret"?
> +}
> +
> +static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
> + struct ublk_io *io, __u64 buf_addr)
> +{
> + struct ublk_device *ub = ubq->dev;
> + int ret;
> +
> + /*
> + * When handling FETCH command for setting up ublk uring queue,
> + * ub->mutex is the innermost lock, and we won't block for handling
> + * FETCH, so it is fine even for IO_URING_F_NONBLOCK.
> + */
> + mutex_lock(&ub->mutex);
> + ret = ublk_config_io_buf(ubq, io, cmd, buf_addr, NULL);
> + if (!ret)
> + ret = __ublk_fetch(cmd, ubq, io);
How come the order of operations was switched here? ublk_fetch()
previously checked ublk_queue_ready(ubq) and io->flags &
UBLK_IO_FLAG_ACTIVE first, which seems necessary to prevent
overwriting a ublk_io that has already been fetched.
Best,
Caleb
> mutex_unlock(&ub->mutex);
> return ret;
> }
> --
> 2.47.0
>
