io_uring: add support for sendmsg()

This is done through IORING_OP_SENDMSG. There's a new sqe->msg_flags
for the flags argument, and the msghdr struct is passed in the
sqe->addr field.

We use MSG_DONTWAIT to force an inline fast path if sendmsg() doesn't
block, and punt to async execution if it would have.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9f0ef49..5d4cd8c 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1390,6 +1390,43 @@ static int io_sync_file_range(struct io_kiocb *req,
        return 0;
 }
 
+static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+                     bool force_nonblock)
+{
+#if defined(CONFIG_NET)
+       struct socket *sock;
+       int ret;
+
+       if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+               return -EINVAL;
+
+       sock = sock_from_file(req->file, &ret);
+       if (sock) {
+               struct user_msghdr __user *msg;
+               unsigned flags;
+
+               flags = READ_ONCE(sqe->msg_flags);
+               if (flags & MSG_DONTWAIT)
+                       req->flags |= REQ_F_NOWAIT;
+               else if (force_nonblock)
+                       flags |= MSG_DONTWAIT;
+
+               msg = (struct user_msghdr __user *) (unsigned long)
+                       READ_ONCE(sqe->addr);
+
+               ret = __sys_sendmsg_sock(sock, msg, flags);
+               if (force_nonblock && ret == -EAGAIN)
+                       return ret;
+       }
+
+       io_cqring_add_event(req->ctx, sqe->user_data, ret);
+       io_put_req(req);
+       return 0;
+#else
+       return -EOPNOTSUPP;
+#endif
+}
+
 static void io_poll_remove_one(struct io_kiocb *req)
 {
        struct io_poll_iocb *poll = &req->poll;
@@ -1675,6 +1712,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
        case IORING_OP_SYNC_FILE_RANGE:
                ret = io_sync_file_range(req, s->sqe, force_nonblock);
                break;
+       case IORING_OP_SENDMSG:
+               ret = io_sendmsg(req, s->sqe, force_nonblock);
+               break;
        default:
                ret = -EINVAL;
                break;

diff --git a/include/linux/socket.h b/include/linux/socket.h
index b57cd8b..9d770ef 100644 (file)
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -12,6 +12,7 @@
 
 struct pid;
 struct cred;
+struct socket;
 
 #define __sockaddr_check_size(size)    \
        BUILD_BUG_ON(((size) > sizeof(struct __kernel_sockaddr_storage)))
@@ -374,6 +375,9 @@ extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg,
 extern int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg,
                          unsigned int vlen, unsigned int flags,
                          bool forbid_cmsg_compat);
+extern long __sys_sendmsg_sock(struct socket *sock,
+                              struct user_msghdr __user *msg,
+                              unsigned int flags);
 
 /* helpers which do the actual work for syscalls */
 extern int __sys_recvfrom(int fd, void __user *ubuf, size_t size,

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 10b7c45..d74742d 100644 (file)
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -27,6 +27,7 @@ struct io_uring_sqe {
                __u32           fsync_flags;
                __u16           poll_events;
                __u32           sync_range_flags;
+               __u32           msg_flags;
        };
        __u64   user_data;      /* data to be passed back at completion time */
        union {
@@ -58,6 +59,7 @@ struct io_uring_sqe {
 #define IORING_OP_POLL_ADD     6
 #define IORING_OP_POLL_REMOVE  7
 #define IORING_OP_SYNC_FILE_RANGE      8
+#define IORING_OP_SENDMSG      9
 
 /*
  * sqe->fsync_flags

diff --git a/net/socket.c b/net/socket.c
index bffec46..b953694 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -2313,6 +2313,13 @@ out_freeiov:
 /*
  *     BSD sendmsg interface
  */
+long __sys_sendmsg_sock(struct socket *sock, struct user_msghdr __user *msg,
+                       unsigned int flags)
+{
+       struct msghdr msg_sys;
+
+       return ___sys_sendmsg(sock, msg, &msg_sys, flags, NULL, 0);
+}
 
 long __sys_sendmsg(int fd, struct user_msghdr __user *msg, unsigned int flags,
                   bool forbid_cmsg_compat)