netdev - Re: [PATCH net] net: avoid an indirect call in ____sys

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Date:   Fri, 06 Dec 2019 12:06:59 -0800 (PST)
From:   David Miller <davem@...emloft.net>
To:     edumazet@...gle.com
Cc:     netdev@...r.kernel.org, eric.dumazet@...il.com, pabeni@...hat.com,
        David.Laight@...lab.com
Subject: Re: [PATCH net] net: avoid an indirect call in ____sys_recvmsg()

From: Eric Dumazet <edumazet@...gle.com>
Date: Fri,  6 Dec 2019 09:38:36 -0800

> 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@...gle.com>

Applied, thanks Eric.