On Mon, Apr 28, 2025 at 2:44 AM Ming Lei <ming.lei@xxxxxxxxxx> wrote:
>
> Add 'struct io_buf_data' for register/unregister bvec buffer, and
> prepare for supporting to register buffer into one specified io_uring
> context by its FD.
>
> No functional change.
I'm not a big fan of this change. Passing the arguments by reference
instead of in registers makes io_buffer_register_bvec() more expensive
to call. And it's a strange API for io_buffer_unregister_bvec() to
take a full struct io_buf_data but only use the index field.
Best,
Caleb
>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> drivers/block/ublk_drv.c | 13 ++++++++++---
> include/linux/io_uring/cmd.h | 11 ++++++++---
> io_uring/rsrc.c | 12 ++++++++----
> 3 files changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 0d82014679f8..ac56482b55f5 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -1925,6 +1925,10 @@ static int ublk_register_io_buf(struct io_uring_cmd *cmd,
> {
> struct ublk_device *ub = cmd->file->private_data;
> const struct ublk_io *io = &ubq->ios[tag];
> + struct io_buf_data data = {
> + .index = index,
> + .release = ublk_io_release,
> + };
> struct request *req;
> int ret;
>
> @@ -1938,8 +1942,8 @@ static int ublk_register_io_buf(struct io_uring_cmd *cmd,
> if (!req)
> return -EINVAL;
>
> - ret = io_buffer_register_bvec(cmd, req, ublk_io_release, index,
> - issue_flags);
> + data.rq = req;
> + ret = io_buffer_register_bvec(cmd, &data, issue_flags);
> if (ret) {
> ublk_put_req_ref(ubq, req);
> return ret;
> @@ -1953,6 +1957,9 @@ static int ublk_unregister_io_buf(struct io_uring_cmd *cmd,
> unsigned int index, unsigned int issue_flags)
> {
> const struct ublk_io *io = &ubq->ios[tag];
> + struct io_buf_data data = {
> + .index = index,
> + };
>
> if (!ublk_support_zero_copy(ubq))
> return -EINVAL;
> @@ -1960,7 +1967,7 @@ static int ublk_unregister_io_buf(struct io_uring_cmd *cmd,
> if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
> return -EINVAL;
>
> - return io_buffer_unregister_bvec(cmd, index, issue_flags);
> + return io_buffer_unregister_bvec(cmd, &data, issue_flags);
> }
>
> static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
> diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h
> index 0634a3de1782..78fa336a284b 100644
> --- a/include/linux/io_uring/cmd.h
> +++ b/include/linux/io_uring/cmd.h
> @@ -23,6 +23,12 @@ struct io_uring_cmd_data {
> void *op_data;
> };
>
> +struct io_buf_data {
> + unsigned short index;
> + struct request *rq;
> + void (*release)(void *);
> +};
> +
> static inline const void *io_uring_sqe_cmd(const struct io_uring_sqe *sqe)
> {
> return sqe->cmd;
> @@ -140,10 +146,9 @@ static inline struct io_uring_cmd_data *io_uring_cmd_get_async_data(struct io_ur
> return cmd_to_io_kiocb(cmd)->async_data;
> }
>
> -int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
> - void (*release)(void *), unsigned int index,
> +int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct io_buf_data *data,
> unsigned int issue_flags);
> -int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
> +int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, struct io_buf_data *data,
> unsigned int issue_flags);
>
> #endif /* _LINUX_IO_URING_CMD_H */
> diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
> index b4c5f3ee8855..66d2c11e2f46 100644
> --- a/io_uring/rsrc.c
> +++ b/io_uring/rsrc.c
> @@ -918,12 +918,14 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
> return ret;
> }
>
> -int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
> - void (*release)(void *), unsigned int index,
> +int io_buffer_register_bvec(struct io_uring_cmd *cmd,
> + struct io_buf_data *buf,
> unsigned int issue_flags)
> {
> struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
> struct io_rsrc_data *data = &ctx->buf_table;
> + unsigned int index = buf->index;
> + struct request *rq = buf->rq;
> struct req_iterator rq_iter;
> struct io_mapped_ubuf *imu;
> struct io_rsrc_node *node;
> @@ -963,7 +965,7 @@ int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
> imu->folio_shift = PAGE_SHIFT;
> imu->nr_bvecs = nr_bvecs;
> refcount_set(&imu->refs, 1);
> - imu->release = release;
> + imu->release = buf->release;
> imu->priv = rq;
> imu->is_kbuf = true;
> imu->dir = 1 << rq_data_dir(rq);
> @@ -980,11 +982,13 @@ int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
> }
> EXPORT_SYMBOL_GPL(io_buffer_register_bvec);
>
> -int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
> +int io_buffer_unregister_bvec(struct io_uring_cmd *cmd,
> + struct io_buf_data *buf,
> unsigned int issue_flags)
> {
> struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
> struct io_rsrc_data *data = &ctx->buf_table;
> + unsigned index = buf->index;
> struct io_rsrc_node *node;
> int ret = 0;
>
> --
> 2.47.0
>
