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authorBrandon L Black <blblack@gmail.com>2010-03-26 16:18:03 +0000
committerDavid S. Miller <davem@davemloft.net>2010-03-27 08:29:01 -0700
commit71c5c1595c04852d6fbf3c4882b47b30b61a4d32 (patch)
treed95c64c5b752d37e7d1235e52f0c1fceb816c2ec
parentf49c57e141c7f53353e4265a31dc2324e6215037 (diff)
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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 <blblack@gmail.com> Acked-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/socket.h1
-rw-r--r--net/socket.c4
2 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 7b3aae2052a..354cc5617f8 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 769c386bd42..f55ffe9f8c8 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);