On Tue, 18 Dec 2018 14:33:21 -0600
Tom Zanussi <zanussi@xxxxxxxxxx> wrote:
> From: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
>
> There's no need to use strlen() for static strings when the length is
> already known, so update trace_events_hist.c with sizeof() for those
> cases.
>
> Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
> ---
> kernel/trace/trace_events_hist.c | 38 +++++++++++++++++++-------------------
> 1 file changed, 19 insertions(+), 19 deletions(-)
>
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index d29bf8a8e1dd..25d06b3ae1f6 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -507,7 +507,7 @@ static int synth_field_string_size(char *type)
> start = strstr(type, "char[");
> if (start == NULL)
> return -EINVAL;
> - start += strlen("char[");
> + start += sizeof("char[") - 1;
>
> end = strchr(type, ']');
> if (!end || end < start)
> @@ -1843,8 +1843,8 @@ static int parse_action(char *str, struct hist_trigger_attrs *attrs)
> if (attrs->n_actions >= HIST_ACTIONS_MAX)
> return ret;
>
> - if ((strncmp(str, "onmatch(", strlen("onmatch(")) == 0) ||
> - (strncmp(str, "onmax(", strlen("onmax(")) == 0)) {
> + if ((strncmp(str, "onmatch(", sizeof("onmatch(") - 1) == 0) ||
> + (strncmp(str, "onmax(", sizeof("onmax(") - 1) == 0)) {
> attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
> if (!attrs->action_str[attrs->n_actions]) {
> ret = -ENOMEM;
> @@ -1861,34 +1861,34 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
> {
> int ret = 0;
>
> - if ((strncmp(str, "key=", strlen("key=")) == 0) ||
> - (strncmp(str, "keys=", strlen("keys=")) == 0)) {
> + if ((strncmp(str, "key=", sizeof("key=") - 1) == 0) ||
> + (strncmp(str, "keys=", sizeof("keys=") - 1) == 0)) {
> attrs->keys_str = kstrdup(str, GFP_KERNEL);
I'll apply this as is, but since there's a lot of these, I wonder if we
should make a marcro for this:
#define strcmp_const(str, str_const) strncmp(str, str_const, sizeof(str_const) - 1)
?
This would help prevent bugs due to typos and bad cut and paste.
-- Steve
> if (!attrs->keys_str) {
> ret = -ENOMEM;
> goto out;
> }
> - } else if ((strncmp(str, "val=", strlen("val=")) == 0) ||
> - (strncmp(str, "vals=", strlen("vals=")) == 0) ||
> - (strncmp(str, "values=", strlen("values=")) == 0)) {
> + } else if ((strncmp(str, "val=", sizeof("val=") - 1) == 0) ||
> + (strncmp(str, "vals=", sizeof("vals=") - 1) == 0) ||
> + (strncmp(str, "values=", sizeof("values=") - 1) == 0)) {
> attrs->vals_str = kstrdup(str, GFP_KERNEL);
> if (!attrs->vals_str) {
> ret = -ENOMEM;
> goto out;
> }
> - } else if (strncmp(str, "sort=", strlen("sort=")) == 0) {
> + } else if (strncmp(str, "sort=", sizeof("sort=") - 1) == 0) {
> attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
> if (!attrs->sort_key_str) {
> ret = -ENOMEM;
> goto out;
> }
> - } else if (strncmp(str, "name=", strlen("name=")) == 0) {
> + } else if (strncmp(str, "name=", sizeof("name=") - 1) == 0) {
> attrs->name = kstrdup(str, GFP_KERNEL);
> if (!attrs->name) {
> ret = -ENOMEM;
> goto out;
> }
> - } else if (strncmp(str, "clock=", strlen("clock=")) == 0) {
> + } else if (strncmp(str, "clock=", sizeof("clock=") - 1) == 0) {
> strsep(&str, "=");
> if (!str) {
> ret = -EINVAL;
> @@ -1901,7 +1901,7 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
> ret = -ENOMEM;
> goto out;
> }
> - } else if (strncmp(str, "size=", strlen("size=")) == 0) {
> + } else if (strncmp(str, "size=", sizeof("size=") - 1) == 0) {
> int map_bits = parse_map_size(str);
>
> if (map_bits < 0) {
> @@ -3497,7 +3497,7 @@ static struct action_data *onmax_parse(char *str)
> if (!onmax_fn_name || !str)
> goto free;
>
> - if (strncmp(onmax_fn_name, "save", strlen("save")) == 0) {
> + if (strncmp(onmax_fn_name, "save", sizeof("save") - 1) == 0) {
> char *params = strsep(&str, ")");
>
> if (!params) {
> @@ -4302,8 +4302,8 @@ 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(", strlen("onmatch(")) == 0) {
> - char *action_str = str + strlen("onmatch(");
> + if (strncmp(str, "onmatch(", sizeof("onmatch(") - 1) == 0) {
> + char *action_str = str + sizeof("onmatch(") - 1;
>
> data = onmatch_parse(tr, action_str);
> if (IS_ERR(data)) {
> @@ -4311,8 +4311,8 @@ static int parse_actions(struct hist_trigger_data *hist_data)
> break;
> }
> data->fn = action_trace;
> - } else if (strncmp(str, "onmax(", strlen("onmax(")) == 0) {
> - char *action_str = str + strlen("onmax(");
> + } else if (strncmp(str, "onmax(", sizeof("onmax(") - 1) == 0) {
> + char *action_str = str + sizeof("onmax(") - 1;
>
> data = onmax_parse(action_str);
> if (IS_ERR(data)) {
> @@ -5548,9 +5548,9 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
> p++;
> continue;
> }
> - if (p >= param + strlen(param) - strlen("if") - 1)
> + if (p >= param + strlen(param) - (sizeof("if") - 1) - 1)
> return -EINVAL;
> - if (*(p + strlen("if")) != ' ' && *(p + strlen("if")) != '\t') {
> + if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
> p++;
> continue;
> }
