From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Safonov <dima@arista.com>
Cc: linux-kernel@vger.kernel.org, David Ahern <dsahern@kernel.org>,
Eric Dumazet <edumazet@google.com>,
Ard Biesheuvel <ardb@kernel.org>,
Bob Gilligan <gilligan@arista.com>,
"David S. Miller" <davem@davemloft.net>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Francesco Ruggeri <fruggeri@arista.com>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>, Jason Baron <jbaron@akamai.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Paolo Abeni <pabeni@redhat.com>,
Salam Noureddine <noureddine@arista.com>,
Steven Rostedt <rostedt@goodmis.org>,
netdev@vger.kernel.org
Subject: Re: [PATCH v5 1/5] jump_label: Prevent key->enabled int overflow
Date: Wed, 23 Nov 2022 11:07:19 +0100 [thread overview]
Message-ID: <Y33w1z01l9EerNwu@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20221122185534.308643-2-dima@arista.com>
On Tue, Nov 22, 2022 at 06:55:30PM +0000, Dmitry Safonov wrote:
> key->enabled is indeed a ref-counter as it's documented in multiple
> places: top comment in jump_label.h, Documentation/staging/static-keys.rst,
> etc.
> +/***
> + * static_key_fast_inc_not_negative - adds a user for a static key
> + * @key: static key that must be already enabled
> + *
> + * The caller must make sure that the static key can't get disabled while
> + * in this function. It doesn't patch jump labels, only adds a user to
> + * an already enabled static key.
> + *
> + * Returns true if the increment was done.
> + */
One more thing; it might be useful to point out that unlike refcount_t
this thing does not saturate but will fail to increment on overflow.
next prev parent reply other threads:[~2022-11-23 10:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-22 18:55 [PATCH v5 0/5] net/tcp: Dynamically disable TCP-MD5 static key Dmitry Safonov
2022-11-22 18:55 ` [PATCH v5 1/5] jump_label: Prevent key->enabled int overflow Dmitry Safonov
2022-11-23 9:55 ` Peter Zijlstra
2022-11-23 14:11 ` Dmitry Safonov
2022-11-23 10:07 ` Peter Zijlstra [this message]
2022-11-22 18:55 ` [PATCH v5 2/5] net/tcp: Separate tcp_md5sig_info allocation into tcp_md5sig_info_add() Dmitry Safonov
2022-11-22 18:55 ` [PATCH v5 3/5] net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction Dmitry Safonov
2022-11-22 18:55 ` [PATCH v5 4/5] net/tcp: Do cleanup on tcp_md5_key_copy() failure Dmitry Safonov
2022-11-22 18:55 ` [PATCH v5 5/5] net/tcp: Separate initialization of twsk Dmitry Safonov
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