[PATCH RFC 1/4] net: socket: add support for async operations

@@ -25,6 +25,7 @@
 #include <linux/kmemcheck.h>
 #include <linux/rcupdate.h>
 #include <linux/jump_label.h>
+#include <linux/aio.h>
 #include <uapi/linux/net.h>
 
 struct poll_table_struct;

@@ -173,6 +174,11 @@ struct proto_ops {
 	 */
 	int		(*recvmsg)   (struct socket *sock, struct msghdr *m,
 				      size_t total_len, int flags);
+	int		(*aio_sendmsg)(struct kiocb *iocb, struct socket *sock,
+				       struct msghdr *m, size_t total_len);
+	int		(*aio_recvmsg)(struct kiocb *iocb, struct socket *sock,
+				       struct msghdr *m, size_t total_len,
+				       int flags);
 	int		(*mmap)	     (struct file *file, struct socket *sock,
 				      struct vm_area_struct * vma);
 	ssize_t		(*sendpage)  (struct socket *sock, struct page *page,

@@ -132,6 +132,11 @@ static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
 				struct pipe_inode_info *pipe, size_t len,
 				unsigned int flags);
 
+static ssize_t sock_aio_read(struct kiocb *iocb, const struct iovec *iov,
+			     unsigned long nr_segs, loff_t loff);
+static ssize_t sock_aio_write(struct kiocb *iocb, const struct iovec *iov,
+			      unsigned long nr_segs, loff_t loff);
+
 /*
  *	Socket files have a set of 'special' operations as well as the generic file ones. These don't appear
  *	in the operation structures but are done directly via the socketcall() multiplexor.

@@ -144,6 +149,8 @@ static const struct file_operations socket_file_ops = {
 	.write =	new_sync_write,
 	.read_iter =	sock_read_iter,
 	.write_iter =	sock_write_iter,
+	.aio_read =	sock_aio_read,
+	.aio_write =	sock_aio_write,
 	.poll =		sock_poll,
 	.unlocked_ioctl = sock_ioctl,
 #ifdef CONFIG_COMPAT

@@ -836,6 +843,63 @@ static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	return res;
 }
 
+static ssize_t sock_aio_read(struct kiocb *iocb, const struct iovec *iov,
+			     unsigned long nr_segs, loff_t loff)
+{
+	struct file *file = iocb->ki_filp;
+	struct socket *sock = file->private_data;
+	struct iov_iter iter;
+	struct msghdr msg = {0};
+	ssize_t res;
+
+	if (file->f_flags & O_NONBLOCK)
+		msg.msg_flags = MSG_DONTWAIT;
+
+	if (iocb->ki_pos != 0)
+		return -ESPIPE;
+
+	if (iocb->ki_nbytes == 0)
+		return 0;
+
+	if (sock->ops->aio_recvmsg) {
+		iov_iter_init(&iter, READ, iov, nr_segs, iocb->ki_nbytes);
+		msg.msg_iter = iter;
+		res = sock->ops->aio_recvmsg(iocb, sock, &msg,
+					     iocb->ki_nbytes, msg.msg_flags);
+	} else {
+		res = -EOPNOTSUPP;
+	}
+	return res;
+}
+
+static ssize_t sock_aio_write(struct kiocb *iocb, const struct iovec *iov,
+			      unsigned long nr_segs, loff_t loff)
+{
+	struct file *file = iocb->ki_filp;
+	struct socket *sock = file->private_data;
+	struct iov_iter iter;
+	struct msghdr msg = {0};
+	ssize_t res;
+
+	if (iocb->ki_pos != 0)
+		return -ESPIPE;
+
+	if (file->f_flags & O_NONBLOCK)
+		msg.msg_flags = MSG_DONTWAIT;
+
+	if (sock->type == SOCK_SEQPACKET)
+		msg.msg_flags |= MSG_EOR;
+
+	if (sock->ops->aio_sendmsg) {
+		iov_iter_init(&iter, WRITE, iov, nr_segs, iocb->ki_nbytes);
+		msg.msg_iter = iter;
+		res = sock->ops->aio_sendmsg(iocb, sock, &msg, iocb->ki_nbytes);
+	} else {
+		res = -EOPNOTSUPP;
+	}
+	return res;
+}
+
 /*
  * Atomic setting of ioctl hooks to avoid race
  * with module unload.