Commit 9cda70f6 authored by Anuj Gupta's avatar Anuj Gupta Committed by Jens Axboe
Browse files

io_uring: introduce fixed buffer support for io_uring_cmd 



Add IORING_URING_CMD_FIXED flag that is to be used for sending io_uring
command with previously registered buffers. User-space passes the buffer
index in sqe->buf_index, same as done in read/write variants that uses
fixed buffers.

Signed-off-by: default avatarAnuj Gupta <anuj20.g@samsung.com>
Signed-off-by: default avatarKanchan Joshi <joshi.k@samsung.com>
Link: https://lore.kernel.org/r/20220930062749.152261-3-anuj20.g@samsung.com


[axboe: shuffle valid flags check before acting on it]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a9216fac

include/linux/io_uring.h

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ struct io_uring_cmd { 
		void *cookie;

	};

	u32		cmd_op;

	u32		pad;

	u32		flags;

	u8		pdu[32]; /* available inline for free use */

};

include/uapi/linux/io_uring.h

+9 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ struct io_uring_sqe { 
		__u32		hardlink_flags;

		__u32		xattr_flags;

		__u32		msg_ring_flags;

		__u32		uring_cmd_flags;

	};

	__u64	user_data;	/* data to be passed back at completion time */

	/* pack this to avoid bogus arm OABI complaints */
@@ -219,6 +220,14 @@ enum io_uring_op { 
	IORING_OP_LAST,

};



/*

 * sqe->uring_cmd_flags

 * IORING_URING_CMD_FIXED	use registered buffer; pass thig flag

 *				along with setting sqe->buf_index.

 */

#define IORING_URING_CMD_FIXED	(1U << 0)





/*

 * sqe->fsync_flags

 */

io_uring/uring_cmd.c

+18 −1
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <linux/file.h>

#include <linux/io_uring.h>

#include <linux/security.h>

#include <linux/nospec.h>



#include <uapi/linux/io_uring.h>
@@ -77,8 +78,24 @@ int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
{

	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);



	if (sqe->rw_flags || sqe->__pad1)

	if (sqe->__pad1)

		return -EINVAL;



	ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags);

	if (ioucmd->flags & ~IORING_URING_CMD_FIXED)

		return -EINVAL;



	if (ioucmd->flags & IORING_URING_CMD_FIXED) {

		struct io_ring_ctx *ctx = req->ctx;

		u16 index;



		req->buf_index = READ_ONCE(sqe->buf_index);

		if (unlikely(req->buf_index >= ctx->nr_user_bufs))

			return -EFAULT;

		index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);

		req->imu = ctx->user_bufs[index];

		io_req_set_rsrc_node(req, ctx, 0);

	}

	ioucmd->cmd = sqe->cmd;

	ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);

	return 0;