From f092276d85b82504e8a07498f4e9e0c51f06745c Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Mon, 7 Mar 2016 14:11:03 -0800 Subject: net: Add MSG_BATCH flag Add a new msg flag called MSG_BATCH. This flag is used in sendmsg to indicate that more messages will follow (i.e. a batch of messages is being sent). This is similar to MSG_MORE except that the following messages are not merged into one packet, they are sent individually. sendmmsg is updated so that each contained message except for the last one is marked as MSG_BATCH. MSG_BATCH is a performance optimization in cases where a socket implementation can benefit by transmitting packets in a batch. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/socket.h | 1 + net/socket.c | 5 +++++ 2 files changed, 6 insertions(+) diff --git a/include/linux/socket.h b/include/linux/socket.h index 5bf59c8493b7..d834af22a460 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -274,6 +274,7 @@ struct ucred { #define MSG_MORE 0x8000 /* Sender will send more */ #define MSG_WAITFORONE 0x10000 /* recvmmsg(): block until 1+ packets avail */ #define MSG_SENDPAGE_NOTLAST 0x20000 /* sendpage() internal : not the last page */ +#define MSG_BATCH 0x40000 /* sendmmsg(): more messages coming */ #define MSG_EOF MSG_FIN #define MSG_FASTOPEN 0x20000000 /* Send data in TCP SYN */ diff --git a/net/socket.c b/net/socket.c index 0dd4dd818f41..886649c88d8f 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2008,6 +2008,7 @@ int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, struct compat_mmsghdr __user *compat_entry; struct msghdr msg_sys; struct used_address used_address; + unsigned int oflags = flags; if (vlen > UIO_MAXIOV) vlen = UIO_MAXIOV; @@ -2022,8 +2023,12 @@ int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, entry = mmsg; compat_entry = (struct compat_mmsghdr __user *)mmsg; err = 0; + flags |= MSG_BATCH; while (datagrams < vlen) { + if (datagrams == vlen - 1) + flags = oflags; + if (MSG_CMSG_COMPAT & flags) { err = ___sys_sendmsg(sock, (struct user_msghdr __user *)compat_entry, &msg_sys, flags, &used_address, MSG_EOR); -- cgit v1.2.3