From b841b901c452d92610f739a36e54978453528876 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 22 May 2023 13:11:10 +0100 Subject: [PATCH] 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: David Howells Reviewed-by: Willem de Bruijn cc: Jens Axboe cc: Matthew Wilcox Signed-off-by: Jakub Kicinski --- include/linux/socket.h | 3 +++ io_uring/net.c | 2 ++ net/socket.c | 2 ++ 3 files changed, 7 insertions(+) diff --git a/include/linux/socket.h b/include/linux/socket.h index 13c3a23..bd1cc32 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -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 diff --git a/io_uring/net.c b/io_uring/net.c index 89e8390..f7cbb3c 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -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; diff --git a/net/socket.c b/net/socket.c index b7e01d0..3df96e9 100644 --- a/net/socket.c +++ b/net/socket.c @@ -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) -- 2.7.4