net: socket: add support for async operations

Add support for async operations.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: tstruk

include/linux/socket.h

@@ -51,6 +51,7 @@ struct msghdr {
 	void		*msg_control;	/* ancillary data */
 	__kernel_size_t	msg_controllen;	/* ancillary data buffer length */
 	unsigned int	msg_flags;	/* flags on received message */
+	struct kiocb	*msg_iocb;	/* ptr to iocb for async requests */
 };
 
 struct user_msghdr {

net/compat.c

@@ -79,6 +79,8 @@ ssize_t get_compat_msghdr(struct msghdr *kmsg,
 	if (nr_segs > UIO_MAXIOV)
 		return -EMSGSIZE;
 
+	kmsg->msg_iocb = NULL;
+
 	err = compat_rw_copy_check_uvector(save_addr ? READ : WRITE,
 					   compat_ptr(uiov), nr_segs,
 					   UIO_FASTIOV, *iov, iov);

net/socket.c

@@ -798,7 +798,8 @@ static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct file *file = iocb->ki_filp;
 	struct socket *sock = file->private_data;
-	struct msghdr msg = {.msg_iter = *to};
+	struct msghdr msg = {.msg_iter = *to,
+			     .msg_iocb = iocb};
 	ssize_t res;
 
 	if (file->f_flags & O_NONBLOCK)
@@ -819,7 +820,8 @@ static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct socket *sock = file->private_data;
-	struct msghdr msg = {.msg_iter = *from};
+	struct msghdr msg = {.msg_iter = *from,
+			     .msg_iocb = iocb};
 	ssize_t res;
 
 	if (iocb->ki_pos != 0)
@@ -1894,6 +1896,8 @@ static ssize_t copy_msghdr_from_user(struct msghdr *kmsg,
 	if (nr_segs > UIO_MAXIOV)
 		return -EMSGSIZE;
 
+	kmsg->msg_iocb = NULL;
+
 	err = rw_copy_check_uvector(save_addr ? READ : WRITE,
 				    uiov, nr_segs,
 				    UIO_FASTIOV, *iov, iov);