Commit 1af66221 authored Dec 06, 2019 by Eric Dumazet Committed by David S. Miller Dec 06, 2019

net: avoid an indirect call in ____sys_recvmsg()



CONFIG_RETPOLINE=y made indirect calls expensive.

gcc seems to add an indirect call in ____sys_recvmsg().

Rewriting the code slightly makes sure to avoid this indirection.

Alternative would be to not call sock_recvmsg() and instead
use security_socket_recvmsg() and sock_recvmsg_nosec(),
but this is less readable IMO.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: David Laight <David.Laight@aculab.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 462f8554

net/socket.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -2559,7 +2559,12 @@ static int ____sys_recvmsg(struct socket sock, struct msghdr msg_sys,

		if (sock->file->f_flags & O_NONBLOCK)
		flags \|= MSG_DONTWAIT;
		err = (nosec ? sock_recvmsg_nosec : sock_recvmsg)(sock, msg_sys, flags);

		if (unlikely(nosec))
		err = sock_recvmsg_nosec(sock, msg_sys, flags);
		else
		err = sock_recvmsg(sock, msg_sys, flags);

		if (err < 0)
		goto out;
		len = err;

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