[for-next][PATCH 24/24] tracing: Use strncmp_prefix() helper for histogram code

Steven Rostedt
2018-12-21T17:57:14Z

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
strncmp_prefix() helper macro instead that removes the need for having two
copies of the constant string.

Cc: Tom Zanussi <zanussi@linux.intel.com>
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..a11653ac7087 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 ((strncmp_prefix(str, "onmatch(") == 0) ||
+ (strncmp_prefix(str, "onmax(") == 0)) {
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 ((strncmp_prefix(str, "key=") == 0) ||
+ (strncmp_prefix(str, "keys=") == 0)) {
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 ((strncmp_prefix(str, "val=") == 0) ||
+ (strncmp_prefix(str, "vals=") == 0) ||
+ (strncmp_prefix(str, "values=") == 0)) {
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 (strncmp_prefix(str, "sort=") == 0) {
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 (strncmp_prefix(str, "name=") == 0) {
attrs->name = kstrdup(str, GFP_KERNEL);
if (!attrs->name) {
ret = -ENOMEM;
goto out;
}
- } else if (strncmp(str, "clock=", sizeof("clock=") - 1) == 0) {
+ } else if (strncmp_prefix(str, "clock=") == 0) {
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 (strncmp_prefix(str, "size=") == 0) {
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 (strncmp_prefix(onmax_fn_name, "save") == 0) {
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 (strncmp_prefix(str, "onmatch(") == 0) {
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 (strncmp_prefix(str, "onmax(") == 0) {
char *action_str = str + sizeof("onmax(") - 1;

data = onmax_parse(action_str);
--
2.19.2