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Date:   Mon, 10 Jul 2023 18:43:53 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
        Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH v1 1/1] f2fs: Use return value of strreplace()
Message-ID: <20230710184353.09640aee@gandalf.local.home>
In-Reply-To: <20230628150243.17771-1-andriy.shevchenko@linux.intel.com>
References: <20230628150243.17771-1-andriy.shevchenko@linux.intel.com>
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On Wed, 28 Jun 2023 18:02:43 +0300
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> Since strreplace() returns the pointer to the string itself,
> we may use it directly in the code.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  include/trace/events/f2fs.h | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> index 793f82cc1515..f5994515290c 100644
> --- a/include/trace/events/f2fs.h
> +++ b/include/trace/events/f2fs.h
> @@ -2234,13 +2234,11 @@ DECLARE_EVENT_CLASS(f2fs__rw_start,
>  		 * because this screws up the tooling that parses
>  		 * the traces.
>  		 */
> -		__assign_str(pathbuf, pathname);
> -		(void)strreplace(__get_str(pathbuf), ' ', '_');
> +		__assign_str(pathbuf, strreplace(pathname, ' ', '_'));

But this modifies the pathname that is passed into the trace event, which
is something that a trace point should never do! In fact, the char
*pathname, really should be a const char * (for which this would fail to
build).

Note, I went to look for these events and I can not find where they are
used. Should these events just be deleted?

-- Steve


>  		__entry->offset = offset;
>  		__entry->bytes = bytes;
>  		__entry->i_size = i_size_read(inode);
> -		__assign_str(cmdline, command);
> -		(void)strreplace(__get_str(cmdline), ' ', '_');
> +		__assign_str(cmdline, strreplace(command, ' ', '_'));
>  		__entry->pid = pid;
>  		__entry->ino = inode->i_ino;
>  	),