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 <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/socket.c b/net/socket.c
index 0dd4dd8..886649c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2008,6 +2008,7 @@
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 @@
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);