From: Borislav Petkov <bp@alien8.de>
To: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
Jiri Kosina <jkosina@suse.cz>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Chris von Recklinghausen <crecklin@redhat.com>,
Jason Baron <jbaron@akamai.com>, Scott Wood <swood@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Clark Williams <williams@redhat.com>,
x86@kernel.org
Subject: Re: [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper
Date: Tue, 5 Feb 2019 08:22:20 +0100 [thread overview]
Message-ID: <20190205072220.GD21801@zn.tnic> (raw)
In-Reply-To: <36237a0ee38d6c98d080d3fee2921501d8788e4d.1549308412.git.bristot@redhat.com>
> Subject: Re: [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper
s/the/a/
On Mon, Feb 04, 2019 at 08:58:55PM +0100, Daniel Bristot de Oliveira wrote:
> Move the check of if a jump_entry is valid to a function.
s/of //
> diff --git a/kernel/jump_label.c b/kernel/jump_label.c
> index 288d630da22d..456c0d7cbb5b 100644
> --- a/kernel/jump_label.c
> +++ b/kernel/jump_label.c
> @@ -374,22 +374,32 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry)
> return enabled ^ branch;
> }
>
> +bool jump_label_can_update_check(struct jump_entry *entry, bool init)
static.
Also, "jump_label_can_update" is sufficient for a name AFAICT.
> +{
> + /*
> + * An entry->code of 0 indicates an entry which has been
> + * disabled because it was in an init text area.
> + */
> + if (init || !jump_entry_is_init(entry)) {
> + if (!kernel_text_address(jump_entry_code(entry))) {
> + WARN_ONCE(1, "can't patch jump_label at %pS",
> + (void *)jump_entry_code(entry));
> + return 0;
> + }
> + return 1;
> + }
> + return 0;
Those should be bools which it returns, no?
Also, I'd do the function this way, to make it more readable and not
have three returns back-to-back. :)
/*
* An entry->code of 0 indicates an entry which has been disabled because it
* was in an init text area.
*/
bool jump_label_can_update(struct jump_entry *entry, bool init)
{
if (!init && jump_entry_is_init(entry))
return false;
if (WARN_ON_ONCE(!kernel_text_address(jump_entry_code(entry))),
"can't patch jump_label at %pS", (void *)jump_entry_code(entry))
return false;
return true;
}
That second check could be even:
if (WARN_ON_ONCE(!kernel_text_address(jump_entry_code(entry))),
"can't patch jump_label at %pS", (void *)jump_entry_code(entry))
return false;
but that's not more readable than above, I'd say.
> static void __jump_label_update(struct static_key *key,
> struct jump_entry *entry,
> struct jump_entry *stop,
> bool init)
> {
> for_each_label_entry(key, entry, stop) {
> - /*
> - * An entry->code of 0 indicates an entry which has been
> - * disabled because it was in an init text area.
> - */
> - if (init || !jump_entry_is_init(entry)) {
> - if (kernel_text_address(jump_entry_code(entry)))
> - arch_jump_label_transform(entry, jump_label_type(entry));
> - else
> - WARN_ONCE(1, "can't patch jump_label at %pS",
> - (void *)jump_entry_code(entry));
> + if (jump_label_can_update_check(entry, init)) {
> + arch_jump_label_transform(entry,
> + jump_label_type(entry));
Yeah, let that one stick out.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2019-02-05 7:22 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 19:58 [PATCH V4 0/9] x86/jump_label: Bound IPIs sent when updating a static key Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 1/9] jump_label: Add for_each_label_entry helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper Daniel Bristot de Oliveira
2019-02-05 7:22 ` Borislav Petkov [this message]
2019-02-05 13:50 ` Daniel Bristot de Oliveira
2019-02-05 21:13 ` Borislav Petkov
2019-02-07 13:21 ` Daniel Bristot de Oliveira
2019-02-07 14:08 ` Borislav Petkov
2019-02-07 17:00 ` Daniel Bristot de Oliveira
2019-02-07 17:08 ` Borislav Petkov
2019-02-04 19:58 ` [PATCH V4 3/9] x86/jump_label: Move checking code away from __jump_label_transform() Daniel Bristot de Oliveira
2019-02-05 7:33 ` Borislav Petkov
2019-02-05 15:22 ` Daniel Bristot de Oliveira
2019-02-15 10:05 ` Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 4/9] x86/jump_label: Add __jump_label_set_jump_code() helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 5/9] x86/alternative: Split text_poke_bp() into tree steps Daniel Bristot de Oliveira
2019-02-06 19:07 ` Borislav Petkov
2019-02-08 0:11 ` Steven Rostedt
2019-02-08 0:15 ` Steven Rostedt
2019-02-15 12:47 ` Daniel Bristot de Oliveira
2019-02-21 15:26 ` Steven Rostedt
2019-02-04 19:58 ` [PATCH V4 6/9] jump_label: Sort entries of the same key by the code Daniel Bristot de Oliveira
2019-02-04 19:59 ` [PATCH V4 7/9] x86/alternative: Batch of patch operations Daniel Bristot de Oliveira
2019-02-14 12:53 ` Borislav Petkov
2019-02-14 14:06 ` Steven Rostedt
2019-02-14 14:30 ` Borislav Petkov
2019-02-14 14:40 ` Steven Rostedt
2019-02-14 14:54 ` Borislav Petkov
2019-02-15 16:00 ` Daniel Bristot de Oliveira
2019-02-15 17:20 ` Steven Rostedt
2019-02-04 19:59 ` [PATCH V4 8/9] jump_label: Batch updates if arch supports it Daniel Bristot de Oliveira
2019-02-06 6:34 ` Masami Hiramatsu
2019-02-06 15:59 ` Daniel Bristot de Oliveira
2019-02-14 13:33 ` Borislav Petkov
2019-02-04 19:59 ` [PATCH V4 9/9] x86/jump_label: Batch jump label updates Daniel Bristot de Oliveira
2019-02-06 6:29 ` Masami Hiramatsu
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