net: Add MSG_WAITFORONE flag to recvmmsg (71c5c159) · Commits · 戴 / test

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>

include/linux/socket.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

net/socket.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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);

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