usbip_recv(): switch to sock_recvmsg()

int usbip_recv(struct socket *sock, void *buf, int size)

{

	int result;

	struct msghdr msg;

	struct kvec iov;

	struct kvec iov = {.iov_base = buf, .iov_len = size};

	struct msghdr msg = {.msg_flags = MSG_NOSIGNAL};

	int total = 0;

	/* for blocks of if (usbip_dbg_flag_xmit) */

	char *bp = buf;

	int osize = size;

	iov_iter_kvec(&msg.msg_iter, READ|ITER_KVEC, &iov, 1, size);

	usbip_dbg_xmit("enter\n");

	}

	do {

		int sz = msg_data_left(&msg);

		sock->sk->sk_allocation = GFP_NOIO;

		iov.iov_base    = buf;

		iov.iov_len     = size;

		msg.msg_name    = NULL;

		msg.msg_namelen = 0;

		msg.msg_control = NULL;

		msg.msg_controllen = 0;

		msg.msg_flags      = MSG_NOSIGNAL;

		result = kernel_recvmsg(sock, &msg, &iov, 1, size, MSG_WAITALL);

		result = sock_recvmsg(sock, &msg, MSG_WAITALL);

		if (result <= 0) {

			pr_debug("receive sock %p buf %p size %u ret %d total %d\n",

				 sock, buf, size, result, total);

				 sock, buf + total, sz, result, total);

			goto err;

		}

		size -= result;

		buf += result;

		total += result;

	} while (size > 0);

	} while (msg_data_left(&msg));

	if (usbip_dbg_flag_xmit) {

		if (!in_interrupt())

			pr_debug("interrupt  :");

		pr_debug("receiving....\n");

		usbip_dump_buffer(bp, osize);

		pr_debug("received, osize %d ret %d size %d total %d\n",

			 osize, result, size, total);

		usbip_dump_buffer(buf, size);

		pr_debug("received, osize %d ret %d size %zd total %d\n",

			 size, result, msg_data_left(&msg), total);

	}

	return total;