On Fri, 21 Dec 2018 18:25:07 -0500 Steven Rostedt <[email protected]> wrote:
> On Fri, 21 Dec 2018 15:19:33 -0800 > Joe Perches <[email protected]> wrote: > > > I believe this should be bool. > > > > I don't find a use for non-zero assigned len value in the kernel > > for strncmp and I believe the function should simply be: > > > > static inline bool str_has_prefix(const char *str, const char prefix[]) > > { > > return !strncmp(str, prefix, strlen(prefix)); > > } > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 3bb2b3351e35..e4566b9c2553 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -172,8 +172,8 @@ cache_type_store(struct device *dev, struct > device_attribute *attr, > * it's not worth the risk */ > return -EINVAL; > > - if (strncmp(buf, temp, sizeof(temp) - 1) == 0) { > - buf += sizeof(temp) - 1; > + if ((len = str_has_prefix(buf, temp))) { > + buf += len; > sdkp->cache_override = 1; > } else { > sdkp->cache_override = 0; > > And there's more places like this. > Heck, even the tracing code would like this. From the code that started this entire discussion: -- Steve diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 9d590138f870..632410c6e6c0 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -4342,12 +4342,13 @@ static int parse_actions(struct hist_trigger_data *hist_data) unsigned int i; int ret = 0; char *str; + int len; for (i = 0; i < hist_data->attrs->n_actions; i++) { str = hist_data->attrs->action_str[i]; - if (str_has_prefix(str, "onmatch(")) { - char *action_str = str + sizeof("onmatch(") - 1; + if ((len = str_has_prefix(str, "onmatch("))) { + char *action_str = str + len; data = onmatch_parse(tr, action_str); if (IS_ERR(data)) { @@ -4355,8 +4356,8 @@ static int parse_actions(struct hist_trigger_data *hist_data) break; } data->fn = action_trace; - } else if (str_has_prefix(str, "onmax(")) { - char *action_str = str + sizeof("onmax(") - 1; + } else if ((len = str_has_prefix(str, "onmax("))) { + char *action_str = str + len; data = onmax_parse(action_str); if (IS_ERR(data)) {
