On Mon, Feb 24, 2025 at 01:31:14PM -0800, Keith Busch wrote:
> From: Keith Busch <kbusch@xxxxxxxxxx>
>
> Provide new operations for the user to request mapping an active request
> to an io uring instance's buf_table. The user has to provide the index
> it wants to install the buffer.
>
> A reference count is taken on the request to ensure it can't be
> completed while it is active in a ring's buf_table.
>
> Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
> ---
> drivers/block/ublk_drv.c | 117 +++++++++++++++++++++++-----------
> include/uapi/linux/ublk_cmd.h | 4 ++
> 2 files changed, 85 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 529085181f355..a719d873e3882 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -51,6 +51,9 @@
> /* private ioctl command mirror */
> #define UBLK_CMD_DEL_DEV_ASYNC _IOC_NR(UBLK_U_CMD_DEL_DEV_ASYNC)
>
> +#define UBLK_IO_REGISTER_IO_BUF _IOC_NR(UBLK_U_IO_REGISTER_IO_BUF)
> +#define UBLK_IO_UNREGISTER_IO_BUF _IOC_NR(UBLK_U_IO_UNREGISTER_IO_BUF)
> +
> /* All UBLK_F_* have to be included into UBLK_F_ALL */
> #define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \
> | UBLK_F_URING_CMD_COMP_IN_TASK \
> @@ -201,7 +204,7 @@ static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq,
> int tag);
> static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
> {
> - return ub->dev_info.flags & UBLK_F_USER_COPY;
> + return ub->dev_info.flags & (UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY);
> }
I'd suggest to set UBLK_F_USER_COPY explicitly either from userspace or
kernel side.
One reason is that UBLK_F_UNPRIVILEGED_DEV mode can't work for both.
Thanks,
Ming
