Commit b841b901 authored by David Howells's avatar David Howells Committed by Jakub Kicinski
Browse files

net: Declare MSG_SPLICE_PAGES internal sendmsg() flag 



Declare MSG_SPLICE_PAGES, an internal sendmsg() flag, that hints to a
network protocol that it should splice pages from the source iterator
rather than copying the data if it can.  This flag is added to a list that
is cleared by sendmsg syscalls on entry.

This is intended as a replacement for the ->sendpage() op, allowing a way
to splice in several multipage folios in one go.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 57910a47

include/linux/socket.h

+3 −0
Original line number Diff line number Diff line
@@ -327,6 +327,7 @@ struct ucred { 
					  */



#define MSG_ZEROCOPY	0x4000000	/* Use user data in kernel path */

#define MSG_SPLICE_PAGES 0x8000000	/* Splice the pages from the iterator in sendmsg() */

#define MSG_FASTOPEN	0x20000000	/* Send data in TCP SYN */

#define MSG_CMSG_CLOEXEC 0x40000000	/* Set close_on_exec for file

					   descriptor received through
@@ -337,6 +338,8 @@ struct ucred { 
#define MSG_CMSG_COMPAT	0		/* We never have 32 bit fixups */

#endif



/* Flags to be cleared on entry by sendmsg and sendmmsg syscalls */

#define MSG_INTERNAL_SENDMSG_FLAGS (MSG_SPLICE_PAGES)



/* Setsockoptions(2) level. Thanks to BSD these must match IPPROTO_xxx */

#define SOL_IP		0

io_uring/net.c

+2 −0
Original line number Diff line number Diff line
@@ -389,6 +389,7 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags) 
	if (flags & MSG_WAITALL)

		min_ret = iov_iter_count(&msg.msg_iter);



	flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;

	msg.msg_flags = flags;

	ret = sock_sendmsg(sock, &msg);

	if (ret < min_ret) {
@@ -1136,6 +1137,7 @@ int io_send_zc(struct io_kiocb *req, unsigned int issue_flags) 
		msg_flags |= MSG_DONTWAIT;

	if (msg_flags & MSG_WAITALL)

		min_ret = iov_iter_count(&msg.msg_iter);

	msg_flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;



	msg.msg_flags = msg_flags;

	msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;

net/socket.c

+2 −0
Original line number Diff line number Diff line
@@ -2138,6 +2138,7 @@ int __sys_sendto(int fd, void __user *buff, size_t len, unsigned int flags, 
		msg.msg_name = (struct sockaddr *)&address;

		msg.msg_namelen = addr_len;

	}

	flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;

	if (sock->file->f_flags & O_NONBLOCK)

		flags |= MSG_DONTWAIT;

	msg.msg_flags = flags;
@@ -2483,6 +2484,7 @@ static int ____sys_sendmsg(struct socket *sock, struct msghdr *msg_sys, 
		msg_sys->msg_control = ctl_buf;

		msg_sys->msg_control_is_user = false;

	}

	flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;

	msg_sys->msg_flags = flags;



	if (sock->file->f_flags & O_NONBLOCK)