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>
This commit is contained in:
Brandon L Black 2010-03-26 16:18:03 +00:00 committed by David S. Miller
parent f49c57e141
commit 71c5c1595c
2 changed files with 5 additions and 0 deletions

View file

@ -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

View file

@ -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);