Re: [for-next][PATCH 2/5] tracing: Use str_has_prefix() helper for histogram code

[Tom Zanussi <zanussi@kernel.org>]

Hi Steve,

On Sat, 2018-12-22 at 13:01 -0500, Steven Rostedt wrote:
> On Sat, 22 Dec 2018 11:20:09 -0500
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> > 
> > The tracing histogram code contains a lot of instances of the
> > construct:
> > 
> >  strncmp(str, "const", sizeof("const") - 1)
> > 
> > This can be prone to bugs due to typos or bad cut and paste. Use
> > the
> > str_has_prefix() helper macro instead that removes the need for
> > having two
> > copies of the constant string.
> > 
> > Cc: Tom Zanussi <zanussi@linux.intel.com>
> 
> I have no idea why I copied your intel email. The linux.intel.com
> appears to be no longer active. I'm going to rebase to fix this email
> address.

linux.intel.com is active, but there's no zanussi there, just
tom.zanussi ;-)

So tom.zanussi@linux.intel.com should work fine.

Tom

> 
> -- Steve
> 
> 
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > ---
> >  kernel/trace/trace_events_hist.c | 28 ++++++++++++++--------------
> >  1 file changed, 14 insertions(+), 14 deletions(-)
> > 
> > diff --git a/kernel/trace/trace_events_hist.c
> > b/kernel/trace/trace_events_hist.c
> > index c5448c103770..9d590138f870 100644
> > --- a/kernel/trace/trace_events_hist.c
> > +++ b/kernel/trace/trace_events_hist.c
> > @@ -1881,8 +1881,8 @@ static int parse_action(char *str, struct
> > hist_trigger_attrs *attrs)
> >  	if (attrs->n_actions >= HIST_ACTIONS_MAX)
> >  		return ret;
> >  
> > -	if ((strncmp(str, "onmatch(", sizeof("onmatch(") - 1) =
> > 0) ||
> > -	    (strncmp(str, "onmax(", sizeof("onmax(") - 1) = 0)) {
> > +	if ((str_has_prefix(str, "onmatch(")) ||
> > +	    (str_has_prefix(str, "onmax("))) {
> >  		attrs->action_str[attrs->n_actions] = kstrdup(str,
> > GFP_KERNEL);
> >  		if (!attrs->action_str[attrs->n_actions]) {
> >  			ret = -ENOMEM;
> > @@ -1899,34 +1899,34 @@ static int parse_assignment(char *str,
> > struct hist_trigger_attrs *attrs)
> >  {
> >  	int ret = 0;
> >  
> > -	if ((strncmp(str, "key=", sizeof("key=") - 1) = 0) ||
> > -	    (strncmp(str, "keys=", sizeof("keys=") - 1) = 0)) {
> > +	if ((str_has_prefix(str, "key=")) ||
> > +	    (str_has_prefix(str, "keys="))) {
> >  		attrs->keys_str = kstrdup(str, GFP_KERNEL);
> >  		if (!attrs->keys_str) {
> >  			ret = -ENOMEM;
> >  			goto out;
> >  		}
> > -	} else if ((strncmp(str, "val=", sizeof("val=") - 1) = 0)
> > ||
> > -		 (strncmp(str, "vals=", sizeof("vals=") - 1) = 0)
> > ||
> > -		 (strncmp(str, "values=", sizeof("values=") - 1)
> > = 0)) {
> > +	} else if ((str_has_prefix(str, "val=")) ||
> > +		   (str_has_prefix(str, "vals=")) ||
> > +		   (str_has_prefix(str, "values="))) {
> >  		attrs->vals_str = kstrdup(str, GFP_KERNEL);
> >  		if (!attrs->vals_str) {
> >  			ret = -ENOMEM;
> >  			goto out;
> >  		}
> > -	} else if (strncmp(str, "sort=", sizeof("sort=") - 1) =
> > 0) {
> > +	} else if (str_has_prefix(str, "sort=")) {
> >  		attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
> >  		if (!attrs->sort_key_str) {
> >  			ret = -ENOMEM;
> >  			goto out;
> >  		}
> > -	} else if (strncmp(str, "name=", sizeof("name=") - 1) =
> > 0) {
> > +	} else if (str_has_prefix(str, "name=")) {
> >  		attrs->name = kstrdup(str, GFP_KERNEL);
> >  		if (!attrs->name) {
> >  			ret = -ENOMEM;
> >  			goto out;
> >  		}
> > -	} else if (strncmp(str, "clock=", sizeof("clock=") - 1) =
> > 0) {
> > +	} else if (str_has_prefix(str, "clock=")) {
> >  		strsep(&str, "=");
> >  		if (!str) {
> >  			ret = -EINVAL;
> > @@ -1939,7 +1939,7 @@ static int parse_assignment(char *str, struct
> > hist_trigger_attrs *attrs)
> >  			ret = -ENOMEM;
> >  			goto out;
> >  		}
> > -	} else if (strncmp(str, "size=", sizeof("size=") - 1) =
> > 0) {
> > +	} else if (str_has_prefix(str, "size=")) {
> >  		int map_bits = parse_map_size(str);
> >  
> >  		if (map_bits < 0) {
> > @@ -3558,7 +3558,7 @@ static struct action_data *onmax_parse(char
> > *str)
> >  	if (!onmax_fn_name || !str)
> >  		goto free;
> >  
> > -	if (strncmp(onmax_fn_name, "save", sizeof("save") - 1) =
> > 0) {
> > +	if (str_has_prefix(onmax_fn_name, "save")) {
> >  		char *params = strsep(&str, ")");
> >  
> >  		if (!params) {
> > @@ -4346,7 +4346,7 @@ static int parse_actions(struct
> > hist_trigger_data *hist_data)
> >  	for (i = 0; i < hist_data->attrs->n_actions; i++) {
> >  		str = hist_data->attrs->action_str[i];
> >  
> > -		if (strncmp(str, "onmatch(", sizeof("onmatch(") -
> > 1) = 0) {
> > +		if (str_has_prefix(str, "onmatch(")) {
> >  			char *action_str = str +
> > sizeof("onmatch(") - 1;
> >  
> >  			data = onmatch_parse(tr, action_str);
> > @@ -4355,7 +4355,7 @@ static int parse_actions(struct
> > hist_trigger_data *hist_data)
> >  				break;
> >  			}
> >  			data->fn = action_trace;
> > -		} else if (strncmp(str, "onmax(", sizeof("onmax(")
> > - 1) = 0) {
> > +		} else if (str_has_prefix(str, "onmax(")) {
> >  			char *action_str = str + sizeof("onmax(")
> > - 1;
> >  
> >  			data = onmax_parse(action_str);
> 
>