netdev - Re: [PATCH bpf-next v3 01/10] net: introduce preferred busy-polling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20201123161103.7bb083f9@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Mon, 23 Nov 2020 16:11:03 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     Björn Töpel <bjorn.topel@...il.com>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        Björn Töpel 
        <bjorn.topel@...el.com>, magnus.karlsson@...el.com, ast@...nel.org,
        daniel@...earbox.net, maciej.fijalkowski@...el.com,
        sridhar.samudrala@...el.com, jesse.brandeburg@...el.com,
        qi.z.zhang@...el.com, edumazet@...gle.com,
        jonathan.lemon@...il.com, maximmi@...dia.com
Subject: Re: [PATCH bpf-next v3 01/10] net: introduce preferred busy-polling

On Thu, 19 Nov 2020 09:30:15 +0100 Björn Töpel wrote:
> @@ -105,7 +105,8 @@ static inline void sk_busy_loop(struct sock *sk, int nonblock)
>  	unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
>  
>  	if (napi_id >= MIN_NAPI_ID)
> -		napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk);
> +		napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
> +			       READ_ONCE(sk->sk_prefer_busy_poll));

Perhaps a noob question, but aren't all accesses to the new sk members
under the socket lock? Do we really need the READ_ONCE() / WRITE_ONCE()?