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authorJens Axboe <axboe@kernel.dk>2022-03-10 06:27:26 -0700
committerJens Axboe <axboe@kernel.dk>2022-03-10 09:16:04 -0700
commit4f57f06ce2186c31c3da52386125dc57b1cd6f96 (patch)
tree6f5f47b26c3b1a5c0de6ce92069d8c28f93d7069
parentcc3cec8367cba76a8ae4c271eba8450f3efc1ba3 (diff)
io_uring: add support for IORING_OP_MSG_RING command
This adds support for IORING_OP_MSG_RING, which allows an SQE to signal another ring. That allows either waking up someone waiting on the ring, or even passing a 64-bit value via the user_data field in the CQE. sqe->fd must contain the fd of a ring that should receive the CQE. sqe->off will be propagated to the cqe->user_data on the target ring, and sqe->len will be propagated to cqe->res. The results CQE will have IORING_CQE_F_MSG set in its flags, to indicate that this CQE was generated from a messaging request rather than a SQE issued locally on that ring. This effectively allows passing a 64-bit and a 32-bit quantify between the two rings. This request type has the following request specific error cases: - -EBADFD. Set if the sqe->fd doesn't point to a file descriptor that is of the io_uring type. - -EOVERFLOW. Set if we were not able to deliver a request to the target ring. Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io_uring.c55
-rw-r--r--include/uapi/linux/io_uring.h3
2 files changed, 58 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0f5e999e569f..36b001365a79 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -706,6 +706,12 @@ struct io_hardlink {
int flags;
};
+struct io_msg {
+ struct file *file;
+ u64 user_data;
+ u32 len;
+};
+
struct io_async_connect {
struct sockaddr_storage address;
};
@@ -871,6 +877,7 @@ struct io_kiocb {
struct io_mkdir mkdir;
struct io_symlink symlink;
struct io_hardlink hardlink;
+ struct io_msg msg;
};
u8 opcode;
@@ -1121,6 +1128,9 @@ static const struct io_op_def io_op_defs[] = {
[IORING_OP_MKDIRAT] = {},
[IORING_OP_SYMLINKAT] = {},
[IORING_OP_LINKAT] = {},
+ [IORING_OP_MSG_RING] = {
+ .needs_file = 1,
+ },
};
/* requests with any of those set should undergo io_disarm_next() */
@@ -4322,6 +4332,46 @@ static int io_nop(struct io_kiocb *req, unsigned int issue_flags)
return 0;
}
+static int io_msg_ring_prep(struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
+{
+ if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index ||
+ sqe->rw_flags || sqe->splice_fd_in || sqe->buf_index ||
+ sqe->personality))
+ return -EINVAL;
+
+ if (req->file->f_op != &io_uring_fops)
+ return -EBADFD;
+
+ req->msg.user_data = READ_ONCE(sqe->off);
+ req->msg.len = READ_ONCE(sqe->len);
+ return 0;
+}
+
+static int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_ring_ctx *target_ctx;
+ struct io_msg *msg = &req->msg;
+ int ret = -EOVERFLOW;
+ bool filled;
+
+ target_ctx = req->file->private_data;
+
+ spin_lock(&target_ctx->completion_lock);
+ filled = io_fill_cqe_aux(target_ctx, msg->user_data, msg->len,
+ IORING_CQE_F_MSG);
+ io_commit_cqring(target_ctx);
+ spin_unlock(&target_ctx->completion_lock);
+
+ if (filled) {
+ io_cqring_ev_posted(target_ctx);
+ ret = 0;
+ }
+
+ __io_req_complete(req, issue_flags, ret, 0);
+ return 0;
+}
+
static int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
@@ -6700,6 +6750,8 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return io_symlinkat_prep(req, sqe);
case IORING_OP_LINKAT:
return io_linkat_prep(req, sqe);
+ case IORING_OP_MSG_RING:
+ return io_msg_ring_prep(req, sqe);
}
printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6983,6 +7035,9 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
case IORING_OP_LINKAT:
ret = io_linkat(req, issue_flags);
break;
+ case IORING_OP_MSG_RING:
+ ret = io_msg_ring(req, issue_flags);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 42b2fe84dbcd..8bd4bfdd9a89 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -143,6 +143,7 @@ enum {
IORING_OP_MKDIRAT,
IORING_OP_SYMLINKAT,
IORING_OP_LINKAT,
+ IORING_OP_MSG_RING,
/* this goes last, obviously */
IORING_OP_LAST,
@@ -199,9 +200,11 @@ struct io_uring_cqe {
*
* IORING_CQE_F_BUFFER If set, the upper 16 bits are the buffer ID
* IORING_CQE_F_MORE If set, parent SQE will generate more CQE entries
+ * IORING_CQE_F_MSG If set, CQE was generated with IORING_OP_MSG_RING
*/
#define IORING_CQE_F_BUFFER (1U << 0)
#define IORING_CQE_F_MORE (1U << 1)
+#define IORING_CQE_F_MSG (1U << 2)
enum {
IORING_CQE_BUFFER_SHIFT = 16,