linux-kernel - Re: [PATCH] tracing: Add NOT to filtering logic

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Message-ID: <CAMEtUuwejSGZSMyncPo9GRvy7vnC8Wam-dOdHU+iO0cJkRDeTg@mail.gmail.com>
Date:	Tue, 2 Dec 2014 11:49:58 -0800
From:	Alexei Starovoitov <ast@...mgrid.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Theodore Ts'o" <tytso@....edu>, Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH] tracing: Add NOT to filtering logic

On Tue, Dec 2, 2014 at 9:04 AM, Steven Rostedt <rostedt@...dmis.org> wrote:
>                                                                         \
> -       return match;                                                   \
> +       return match == !pred->not;                                     \

are you sure this one works for !(var & 2) ?
'not' is either 0 or 1, so it works for other macro:
(val == *addr) ^ pred->not

whereas here 'match' is 'int' and
match = (*addr & val)
will not be 0 or 1...

the patch is small, but delicate...
In such cases I trust tests more than code review ;)
Could you add few tests for this to
CONFIG_FTRACE_STARTUP_TEST
part of the file ?
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