Messages in this thread | | | From | Eric Dumazet <> | Date | Thu, 1 Dec 2022 20:38:44 +0100 | Subject | Re: [PATCH v6 3/5] net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction |
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On Wed, Nov 23, 2022 at 6:39 PM Dmitry Safonov <dima@arista.com> wrote: > > To do that, separate two scenarios: > - where it's the first MD5 key on the system, which means that enabling > of the static key may need to sleep; > - copying of an existing key from a listening socket to the request > socket upon receiving a signed TCP segment, where static key was > already enabled (when the key was added to the listening socket). > > Now the life-time of the static branch for TCP-MD5 is until: > - last tcp_md5sig_info is destroyed > - last socket in time-wait state with MD5 key is closed. > > Which means that after all sockets with TCP-MD5 keys are gone, the > system gets back the performance of disabled md5-key static branch. > > While at here, provide static_key_fast_inc() helper that does ref > counter increment in atomic fashion (without grabbing cpus_read_lock() > on CONFIG_JUMP_LABEL=y). This is needed to add a new user for > a static_key when the caller controls the lifetime of another user. > > Signed-off-by: Dmitry Safonov <dima@arista.com> > Acked-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
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