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authorArnaldo Carvalho de Melo <acme@redhat.com>2009-10-13 10:40:10 +0400
committerDavid S. Miller <davem@davemloft.net>2009-10-13 10:40:10 +0400
commita2e2725541fad72416326798c2d7fa4dafb7d337 (patch)
tree6174be11da607e83eb8efb3775114ad4d6e0ca3a /include/linux/socket.h
parentc05e85a06e376f6b6d59e71e5333d707e956d78b (diff)
downloadlinux-a2e2725541fad72416326798c2d7fa4dafb7d337.tar.xz
net: Introduce recvmmsg socket syscall
Meaning receive multiple messages, reducing the number of syscalls and net stack entry/exit operations. Next patches will introduce mechanisms where protocols that want to optimize this operation will provide an unlocked_recvmsg operation. This takes into account comments made by: . Paul Moore: sock_recvmsg is called only for the first datagram, sock_recvmsg_nosec is used for the rest. . Caitlin Bestler: recvmmsg now has a struct timespec timeout, that works in the same fashion as the ppoll one. If the underlying protocol returns a datagram with MSG_OOB set, this will make recvmmsg return right away with as many datagrams (+ the OOB one) it has received so far. . RĂ©mi Denis-Courmont & Steven Whitehouse: If we receive N < vlen datagrams and then recvmsg returns an error, recvmmsg will return the successfully received datagrams, store the error and return it in the next call. This paves the way for a subsequent optimization, sk_prot->unlocked_recvmsg, where we will be able to acquire the lock only at batch start and end, not at every underlying recvmsg call. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/socket.h')
-rw-r--r--include/linux/socket.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 3273a0c5043b..59966f12990c 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -65,6 +65,12 @@ struct msghdr {
unsigned msg_flags;
};
+/* For recvmmsg/sendmmsg */
+struct mmsghdr {
+ struct msghdr msg_hdr;
+ unsigned msg_len;
+};
+
/*
* POSIX 1003.1g - ancillary data object information
* Ancillary data consits of a sequence of pairs of
@@ -312,6 +318,10 @@ extern int move_addr_to_user(struct sockaddr *kaddr, int klen, void __user *uadd
extern int move_addr_to_kernel(void __user *uaddr, int ulen, struct sockaddr *kaddr);
extern int put_cmsg(struct msghdr*, int level, int type, int len, void *data);
+struct timespec;
+
+extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
+ unsigned int flags, struct timespec *timeout);
#endif
#endif /* not kernel and not glibc */
#endif /* _LINUX_SOCKET_H */