From 71c5c1595c04852d6fbf3c4882b47b30b61a4d32 Mon Sep 17 00:00:00 2001 From: Brandon L Black Date: Fri, 26 Mar 2010 16:18:03 +0000 Subject: [PATCH] net: Add MSG_WAITFORONE flag to recvmmsg Add new flag MSG_WAITFORONE for the recvmmsg() syscall. When this flag is specified for a blocking socket, recvmmsg() will only block until at least 1 packet is available. The default behavior is to block until all vlen packets are available. This flag has no effect on non-blocking sockets or when used in combination with MSG_DONTWAIT. Signed-off-by: Brandon L Black Acked-by: Ulrich Drepper Acked-by: Eric Dumazet Acked-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- include/linux/socket.h | 1 + net/socket.c | 4 ++++ 2 files changed, 5 insertions(+) diff --git a/include/linux/socket.h b/include/linux/socket.h index 7b3aae2052a6..354cc5617f8b 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -255,6 +255,7 @@ struct ucred { #define MSG_ERRQUEUE 0x2000 /* Fetch message from error queue */ #define MSG_NOSIGNAL 0x4000 /* Do not generate SIGPIPE */ #define MSG_MORE 0x8000 /* Sender will send more */ +#define MSG_WAITFORONE 0x10000 /* recvmmsg(): block until 1+ packets avail */ #define MSG_EOF MSG_FIN diff --git a/net/socket.c b/net/socket.c index 769c386bd428..f55ffe9f8c87 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2135,6 +2135,10 @@ int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, break; ++datagrams; + /* MSG_WAITFORONE turns on MSG_DONTWAIT after one packet */ + if (flags & MSG_WAITFORONE) + flags |= MSG_DONTWAIT; + if (timeout) { ktime_get_ts(timeout); *timeout = timespec_sub(end_time, *timeout);