1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
4 #include <linux/file.h>
5 #include <linux/slab.h>
6 #include <linux/nospec.h>
7 #include <linux/io_uring.h>
9 #include <uapi/linux/io_uring.h>
13 #include "filetable.h"
26 static int io_msg_ring_data(struct io_kiocb *req)
28 struct io_ring_ctx *target_ctx = req->file->private_data;
29 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
31 if (msg->src_fd || msg->dst_fd || msg->flags)
33 if (target_ctx->flags & IORING_SETUP_R_DISABLED)
36 if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0, true))
42 static void io_double_unlock_ctx(struct io_ring_ctx *ctx,
43 struct io_ring_ctx *octx,
44 unsigned int issue_flags)
46 if (issue_flags & IO_URING_F_UNLOCKED)
47 mutex_unlock(&ctx->uring_lock);
48 mutex_unlock(&octx->uring_lock);
51 static int io_double_lock_ctx(struct io_ring_ctx *ctx,
52 struct io_ring_ctx *octx,
53 unsigned int issue_flags)
56 * To ensure proper ordering between the two ctxs, we can only
57 * attempt a trylock on the target. If that fails and we already have
58 * the source ctx lock, punt to io-wq.
60 if (!(issue_flags & IO_URING_F_UNLOCKED)) {
61 if (!mutex_trylock(&octx->uring_lock))
66 /* Always grab smallest value ctx first. We know ctx != octx. */
68 mutex_lock(&ctx->uring_lock);
69 mutex_lock(&octx->uring_lock);
71 mutex_lock(&octx->uring_lock);
72 mutex_lock(&ctx->uring_lock);
78 static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
80 struct io_ring_ctx *target_ctx = req->file->private_data;
81 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
82 struct io_ring_ctx *ctx = req->ctx;
83 unsigned long file_ptr;
84 struct file *src_file;
87 if (target_ctx == ctx)
89 if (target_ctx->flags & IORING_SETUP_R_DISABLED)
92 ret = io_double_lock_ctx(ctx, target_ctx, issue_flags);
97 if (unlikely(msg->src_fd >= ctx->nr_user_files))
100 msg->src_fd = array_index_nospec(msg->src_fd, ctx->nr_user_files);
101 file_ptr = io_fixed_file_slot(&ctx->file_table, msg->src_fd)->file_ptr;
105 src_file = (struct file *) (file_ptr & FFS_MASK);
108 ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd);
114 if (msg->flags & IORING_MSG_RING_CQE_SKIP)
118 * If this fails, the target still received the file descriptor but
119 * wasn't notified of the fact. This means that if this request
120 * completes with -EOVERFLOW, then the sender must ensure that a
121 * later IORING_OP_MSG_RING delivers the message.
123 if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0, true))
126 io_double_unlock_ctx(ctx, target_ctx, issue_flags);
130 int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
132 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
134 if (unlikely(sqe->buf_index || sqe->personality))
137 msg->user_data = READ_ONCE(sqe->off);
138 msg->len = READ_ONCE(sqe->len);
139 msg->cmd = READ_ONCE(sqe->addr);
140 msg->src_fd = READ_ONCE(sqe->addr3);
141 msg->dst_fd = READ_ONCE(sqe->file_index);
142 msg->flags = READ_ONCE(sqe->msg_ring_flags);
143 if (msg->flags & ~IORING_MSG_RING_CQE_SKIP)
149 int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
151 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
155 if (!io_is_uring_fops(req->file))
159 case IORING_MSG_DATA:
160 ret = io_msg_ring_data(req);
162 case IORING_MSG_SEND_FD:
163 ret = io_msg_send_fd(req, issue_flags);
175 io_req_set_res(req, ret, 0);