Re: [PATCH 1/5] ftrace: remove redundant strsep in mod_callback

From: Steven Rostedt
Date: Tue Sep 29 2015 - 15:11:26 EST


On Tue, 29 Sep 2015 19:46:12 +0300
Dmitry Safonov <0x7f454c46@xxxxxxxxx> wrote:

> By now there isn't any subcommand for mod.
>
> Before:
> sh$ echo '*:mod:ipv6:a' > set_ftrace_filter
> sh$ echo '*:mod:ipv6' > set_ftrace_filter
> had the same results, but now first will result in:
> sh$ echo '*:mod:ipv6:a' > set_ftrace_filter
> -bash: echo: write error: Invalid argument
>
> Also, I clarified ftrace_mod_callback code a little.

Thanks for the patches. I don't have time to look at them at the moment
as I'm trying to finish up some stuff before I leave for LinuxCon EU.

If you don't hear from me by Monday, feel free to ping me again. I'll
be in Dublin (for LinuxCon), but I should be able to take a look at the
patches while I'm there. What do you think keynotes are for ;-)

-- Steve

>
> Signed-off-by: Dmitry Safonov <0x7f454c46@xxxxxxxxx>
> ---
> kernel/trace/ftrace.c | 17 ++++++-----------
> 1 file changed, 6 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index b0623ac..f87401b 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -3564,8 +3564,7 @@ static int
> ftrace_mod_callback(struct ftrace_hash *hash,
> char *func, char *cmd, char *param, int enable)
> {
> - char *mod;
> - int ret = -EINVAL;
> + int ret;
>
> /*
> * cmd == 'mod' because we only registered this func
> @@ -3576,16 +3575,12 @@ ftrace_mod_callback(struct ftrace_hash *hash,
> */
>
> /* we must have a module name */
> - if (!param)
> - return ret;
> -
> - mod = strsep(&param, ":");
> - if (!strlen(mod))
> - return ret;
> + if (!param || !strlen(param))
> + return -EINVAL;
>
> - ret = ftrace_match_module_records(hash, func, mod);
> - if (!ret)
> - ret = -EINVAL;
> + ret = ftrace_match_module_records(hash, func, param);
> + if (ret == 0)
> + return -EINVAL;
> if (ret < 0)
> return ret;
>

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