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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 5/7] trace: make filter_parse_regex() provide the length of substring to compare with
Date: Thu, 5 Feb 2015 21:44:24 +0000	[thread overview]
Message-ID: <20150205214424.GS29656@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20150205162933.4fad48f6@gandalf.local.home>

On Thu, Feb 05, 2015 at 04:29:33PM -0500, Steven Rostedt wrote:
> On Thu,  5 Feb 2015 19:56:38 +0000
> Al Viro <viro@ZenIV.linux.org.uk> wrote:
> 
> > From: Al Viro <viro@zeniv.linux.org.uk>
> > 
> > ... by passing len by address and using it to report the length of
> > substring in question.
> 
> You certainly are very verbose in your change logs.
> 
> What exactly is the purpose of this patch? Clean up? Optimization?
> 
> I can't really tell. Seems like you are just moving the strlen() from
> outside the function into it.

The point is that by now this strlen() is the only thing for which we
NUL-termination of the substring; moving it inside the filter_parse_regex()
is an obviously equivalent transformation and it leaves that one strlen() call
inside filter_parse_regex() the only place where we still care about NUL.

The next commit kills it off completely, at which point we are done with
modifying the string at all.

  reply	other threads:[~2015-02-05 21:44 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-05 19:49 [RFC][PATCHES] constifying ftrace globs Al Viro
2015-02-05 19:56 ` [RFC][PATCH 1/7] trace: fix the glob match in __unregister_ftrace_function_probe() Al Viro
2015-02-05 20:43   ` Steven Rostedt
2015-02-05 22:30     ` Al Viro
2015-02-05 22:52       ` Steven Rostedt
2015-02-05 19:56 ` [RFC][PATCH 2/7] implement memmem() Al Viro
2015-02-05 19:56 ` [RFC][PATCH 3/7] trace_events_filter.c: switch to memcmp() and memmem() for matching Al Viro
2015-02-05 19:56 ` [RFC][PATCH 4/7] ftrace: switch matching to memcmp() and memmem() Al Viro
2015-02-05 19:56 ` [RFC][PATCH 5/7] trace: make filter_parse_regex() provide the length of substring to compare with Al Viro
2015-02-05 21:29   ` Steven Rostedt
2015-02-05 21:44     ` Al Viro [this message]
2015-02-05 22:07       ` Steven Rostedt
2015-02-05 22:46         ` Al Viro
2015-02-06  4:00           ` [RFC][PATCH v2 1/7] trace: fix the glob match in __unregister_ftrace_function_probe() Al Viro
2015-02-06  4:00           ` [RFC][PATCH v2 2/7] implement memmem() Al Viro
2015-02-06 16:19             ` Steven Rostedt
2015-02-06 22:30             ` Rasmus Villemoes
2015-02-06 22:55               ` Steven Rostedt
2015-02-06 23:14                 ` Rasmus Villemoes
2015-02-06  4:00           ` [RFC][PATCH v2 3/7] trace_events_filter.c: switch to memcmp() and memmem() for matching Al Viro
2015-02-06 16:24             ` Steven Rostedt
2015-02-06  4:00           ` [RFC][PATCH v2 4/7] ftrace: switch matching to memcmp() and memmem() Al Viro
2015-02-06  4:00           ` [RFC][PATCH v2 5/7] trace: make filter_parse_regex() provide the length of substring to compare with Al Viro
2015-02-06 18:55             ` Steven Rostedt
2015-02-06  4:00           ` [RFC][PATCH v2 6/7] trace: constify filter_parse_regex(), match_records(), ftrace_match() and ftrace_match_record() Al Viro
2015-02-06 18:56             ` Steven Rostedt
2015-02-06  4:00           ` [RFC][PATCH v2 7/7] trace: constify glob arguments all way up to ftrace_function_set_regexp() Al Viro
2015-02-05 19:56 ` [RFC][PATCH 6/7] trace: constify filter_parse_regex(), match_records(), ftrace_match() and ftrace_match_record() Al Viro
2015-02-05 21:31   ` Steven Rostedt
2015-02-05 19:56 ` [RFC][PATCH 7/7] trace: constify glob arguments all way up to ftrace_function_set_regexp() Al Viro
2020-01-24 23:45 ` [RFC][PATCHES] constifying ftrace globs Steven Rostedt

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