On Mon, Sep 1, 2025 at 3:03 AM Ming Lei <ming.lei@xxxxxxxxxx> wrote:
>
> Introduces the basic structure for a batched I/O feature in the ublk driver.
> It adds placeholder functions and a new file operations structure,
> ublk_ch_batch_io_fops, which will be used for fetching and committing I/O
> commands in batches. Currently, the feature is disabled and returns
> -EOPNOTSUPP.
Technically the "return -EOPNOTSUPP" isn't even reachable since
ublk_ch_batch_io_fops isn't used yet. I think saying "the feature is
disabled" would be sufficient.
Other than that,
Reviewed-by: Caleb Sander Mateos <csander@xxxxxxxxxxxxxxx>
>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> drivers/block/ublk_drv.c | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index f265795a8d57..a0dfad8a56f0 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -256,6 +256,11 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub,
> size_t offset);
> static inline unsigned int ublk_req_build_flags(struct request *req);
>
> +static inline bool ublk_dev_support_batch_io(const struct ublk_device *ub)
> +{
> + return false;
> +}
> +
> static inline struct ublksrv_io_desc *
> ublk_get_iod(const struct ublk_queue *ubq, unsigned tag)
> {
> @@ -2509,6 +2514,12 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
> return ublk_ch_uring_cmd_local(cmd, issue_flags);
> }
>
> +static int ublk_ch_batch_io_uring_cmd(struct io_uring_cmd *cmd,
> + unsigned int issue_flags)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> static inline bool ublk_check_ubuf_dir(const struct request *req,
> int ubuf_dir)
> {
> @@ -2624,6 +2635,16 @@ static const struct file_operations ublk_ch_fops = {
> .mmap = ublk_ch_mmap,
> };
>
> +static const struct file_operations ublk_ch_batch_io_fops = {
> + .owner = THIS_MODULE,
> + .open = ublk_ch_open,
> + .release = ublk_ch_release,
> + .read_iter = ublk_ch_read_iter,
> + .write_iter = ublk_ch_write_iter,
> + .uring_cmd = ublk_ch_batch_io_uring_cmd,
> + .mmap = ublk_ch_mmap,
> +};
> +
> static void ublk_deinit_queue(struct ublk_device *ub, int q_id)
> {
> int size = ublk_queue_cmd_buf_size(ub, q_id);
> @@ -2761,7 +2782,10 @@ static int ublk_add_chdev(struct ublk_device *ub)
> if (ret)
> goto fail;
>
> - cdev_init(&ub->cdev, &ublk_ch_fops);
> + if (ublk_dev_support_batch_io(ub))
> + cdev_init(&ub->cdev, &ublk_ch_batch_io_fops);
> + else
> + cdev_init(&ub->cdev, &ublk_ch_fops);
> ret = cdev_device_add(&ub->cdev, dev);
> if (ret)
> goto fail;
> --
> 2.47.0
>
