Commit cbeb47a7 authored by Breno Leitao's avatar Breno Leitao Committed by Jens Axboe
Browse files

io_uring/msg_ring: Pass custom flags to the cqe 



This patch adds a new flag (IORING_MSG_RING_FLAGS_PASS) in the message
ring operations (IORING_OP_MSG_RING). This new flag enables the sender
to specify custom flags, which will be copied over to cqe->flags in the
receiving ring.  These custom flags should be specified using the
sqe->file_index field.

This mechanism provides additional flexibility when sending messages
between rings.

Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230103160507.617416-1-leitao@debian.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d33a39e5

include/uapi/linux/io_uring.h

+2 −0
Original line number Diff line number Diff line
@@ -347,6 +347,8 @@ enum { 
 *				applicable for IORING_MSG_DATA, obviously.

 */

#define IORING_MSG_RING_CQE_SKIP	(1U << 0)

/* Pass through the flags from sqe->file_index to cqe->flags */

#define IORING_MSG_RING_FLAGS_PASS	(1U << 1)



/*

 * IO completion data structure (Completion Queue Entry)

io_uring/msg_ring.c

+19 −5
Original line number Diff line number Diff line
@@ -13,6 +13,11 @@ 
#include "filetable.h"

#include "msg_ring.h"





/* All valid masks for MSG_RING */

#define IORING_MSG_RING_MASK		(IORING_MSG_RING_CQE_SKIP | \

					IORING_MSG_RING_FLAGS_PASS)



struct io_msg {

	struct file			*file;

	struct file			*src_file;
@@ -21,7 +26,10 @@ struct io_msg { 
	u32 len;

	u32 cmd;

	u32 src_fd;

	union {

		u32 dst_fd;

		u32 cqe_flags;

	};

	u32 flags;

};
@@ -114,9 +122,12 @@ static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags) 
{

	struct io_ring_ctx *target_ctx = req->file->private_data;

	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);

	u32 flags = 0;

	int ret;



	if (msg->src_fd || msg->dst_fd || msg->flags)

	if (msg->src_fd || msg->flags & ~IORING_MSG_RING_FLAGS_PASS)

		return -EINVAL;

	if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd)

		return -EINVAL;

	if (target_ctx->flags & IORING_SETUP_R_DISABLED)

		return -EBADFD;
@@ -124,15 +135,18 @@ static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags) 
	if (io_msg_need_remote(target_ctx))

		return io_msg_exec_remote(req, io_msg_tw_complete);



	if (msg->flags & IORING_MSG_RING_FLAGS_PASS)

		flags = msg->cqe_flags;



	ret = -EOVERFLOW;

	if (target_ctx->flags & IORING_SETUP_IOPOLL) {

		if (unlikely(io_double_lock_ctx(target_ctx, issue_flags)))

			return -EAGAIN;

		if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))

		if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))

			ret = 0;

		io_double_unlock_ctx(target_ctx);

	} else {

		if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))

		if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))

			ret = 0;

	}

	return ret;
@@ -241,7 +255,7 @@ int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	msg->src_fd = READ_ONCE(sqe->addr3);

	msg->dst_fd = READ_ONCE(sqe->file_index);

	msg->flags = READ_ONCE(sqe->msg_ring_flags);

	if (msg->flags & ~IORING_MSG_RING_CQE_SKIP)

	if (msg->flags & ~IORING_MSG_RING_MASK)

		return -EINVAL;



	return 0;