On Wed, 2018-12-19 at 13:46 -0600, Tom Zanussi wrote: > Hi Steve, > > On Wed, 2018-12-19 at 14:40 -0500, Steven Rostedt wrote: > > On Tue, 18 Dec 2018 14:33:21 -0600 > > Tom Zanussi <zanu...@kernel.org> wrote: > > > > > From: Tom Zanussi <tom.zanu...@linux.intel.com> > > > > > > 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.zanu...@linux.intel.com> > > > --- > > > 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. > > > > Yeah, I had considered it but wasn't sure it was worth it. Since > you're suggesting it is, I can send another patch on top of these, or > feel free if you want to too. ;-) >
How's this? [PATCH] tracing: Introduce and use strcmp_const() for hist triggers Provide a new strcmp_const() macro and make use of it instead of the longer and more error-prone strncmp(str, "str", sizeof("str") - 1). Idea-and-macro-by: Steve Rostedt <rost...@goodmis.org> Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com> --- kernel/trace/trace_events_hist.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index c5448c103770..aaf0d2ac4aab 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -22,6 +22,9 @@ #define STR_VAR_LEN_MAX 32 /* must be multiple of sizeof(u64) */ +#define strcmp_const(str, str_const) \ + strncmp(str, str_const, sizeof(str_const) - 1) + struct hist_field; typedef u64 (*hist_field_fn_t) (struct hist_field *field, @@ -1881,8 +1884,8 @@ 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 ((strcmp_const(str, "onmatch(") == 0) || + (strcmp_const(str, "onmax(") == 0)) { attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL); if (!attrs->action_str[attrs->n_actions]) { ret = -ENOMEM; @@ -1899,34 +1902,34 @@ 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 ((strcmp_const(str, "key=") == 0) || + (strcmp_const(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 ((strcmp_const(str, "val=") == 0) || + (strcmp_const(str, "vals=") == 0) || + (strcmp_const(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 (strcmp_const(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 (strcmp_const(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 (strcmp_const(str, "clock=") == 0) { strsep(&str, "="); if (!str) { ret = -EINVAL; @@ -1939,7 +1942,7 @@ 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 (strcmp_const(str, "size=") == 0) { int map_bits = parse_map_size(str); if (map_bits < 0) { @@ -3558,7 +3561,7 @@ 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 (strcmp_const(onmax_fn_name, "save") == 0) { char *params = strsep(&str, ")"); if (!params) { @@ -4346,7 +4349,7 @@ 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 (strcmp_const(str, "onmatch(") == 0) { char *action_str = str + sizeof("onmatch(") - 1; data = onmatch_parse(tr, action_str); @@ -4355,7 +4358,7 @@ 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 (strcmp_const(str, "onmax(") == 0) { char *action_str = str + sizeof("onmax(") - 1; data = onmax_parse(action_str); -- 2.14.1 > Tom