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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>
This commit is contained in:
Eric Dumazet 2019-12-06 09:38:36 -08:00 committed by David S. Miller
parent 462f8554a8
commit 1af66221a6
1 changed files with 6 additions and 1 deletions
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7
net/socket.c
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@ -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;