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Message-ID: <CAJZ5v0gCVoGtoOnXGy7YVBSgahLrLQ-OJoMhYDk1B3jGtNAmnQ@mail.gmail.com>
Date: Thu, 20 Jun 2024 19:53:02 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Mario Limonciello <mario.limonciello@....com>, Perry Yuan <perry.yuan@....com>
Cc: rafael.j.wysocki@...el.com, viresh.kumar@...aro.org,
Borislav.Petkov@....com, gautham.shenoy@....com, Alexander.Deucher@....com,
Xinmei.Huang@....com, Xiaojian.Du@....com, Li.Meng@....com,
linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: update to sysfs_emit for safer buffer handling
On Wed, Jun 19, 2024 at 10:00 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> On 6/19/2024 03:15, Perry Yuan wrote:
> > Replaced sprintf and scnprintf with sysfs_emit and sysfs_emit_at in the
> > cpufreq driver. This ensures safer buffer handling and consistency with
> > sysfs interfaces. Updated show_scaling_available_governors and related
> > functions for compliance with the new API.
> >
> > Signed-off-by: Perry Yuan <perry.yuan@....com>
>
> Reviewed-by: Mario Limonciello <mario.limonciello@....com>
Applied as 6.11 material with some edits in the changelog, thanks!
> > ---
> > drivers/cpufreq/cpufreq.c | 37 ++++++++++++++++++-------------------
> > 1 file changed, 18 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > index e1a4730f4f8c..e76d8e2b4c87 100644
> > --- a/drivers/cpufreq/cpufreq.c
> > +++ b/drivers/cpufreq/cpufreq.c
> > @@ -608,7 +608,7 @@ EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us);
> > static ssize_t show_boost(struct kobject *kobj,
> > struct kobj_attribute *attr, char *buf)
> > {
> > - return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
> > + return sysfs_emit(buf, "%d\n", cpufreq_driver->boost_enabled);
> > }
> >
> > static ssize_t store_boost(struct kobject *kobj, struct kobj_attribute *attr,
> > @@ -738,7 +738,7 @@ static struct cpufreq_governor *cpufreq_parse_governor(char *str_governor)
> > static ssize_t show_##file_name \
> > (struct cpufreq_policy *policy, char *buf) \
> > { \
> > - return sprintf(buf, "%u\n", policy->object); \
> > + return sysfs_emit(buf, "%u\n", policy->object); \
> > }
> >
> > show_one(cpuinfo_min_freq, cpuinfo.min_freq);
> > @@ -759,11 +759,11 @@ static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
> >
> > freq = arch_freq_get_on_cpu(policy->cpu);
> > if (freq)
> > - ret = sprintf(buf, "%u\n", freq);
> > + ret = sysfs_emit(buf, "%u\n", freq);
> > else if (cpufreq_driver->setpolicy && cpufreq_driver->get)
> > - ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
> > + ret = sysfs_emit(buf, "%u\n", cpufreq_driver->get(policy->cpu));
> > else
> > - ret = sprintf(buf, "%u\n", policy->cur);
> > + ret = sysfs_emit(buf, "%u\n", policy->cur);
> > return ret;
> > }
> >
> > @@ -797,9 +797,9 @@ static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
> > unsigned int cur_freq = __cpufreq_get(policy);
> >
> > if (cur_freq)
> > - return sprintf(buf, "%u\n", cur_freq);
> > + return sysfs_emit(buf, "%u\n", cur_freq);
> >
> > - return sprintf(buf, "<unknown>\n");
> > + return sysfs_emit(buf, "<unknown>\n");
> > }
> >
> > /*
> > @@ -808,12 +808,11 @@ static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
> > static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
> > {
> > if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
> > - return sprintf(buf, "powersave\n");
> > + return sysfs_emit(buf, "powersave\n");
> > else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
> > - return sprintf(buf, "performance\n");
> > + return sysfs_emit(buf, "performance\n");
> > else if (policy->governor)
> > - return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
> > - policy->governor->name);
> > + return sysfs_emit(buf, "%s\n", policy->governor->name);
> > return -EINVAL;
> > }
> >
> > @@ -872,7 +871,7 @@ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
> > struct cpufreq_governor *t;
> >
> > if (!has_target()) {
> > - i += sprintf(buf, "performance powersave");
> > + i += sysfs_emit(buf, "performance powersave");
> > goto out;
> > }
> >
> > @@ -881,11 +880,11 @@ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
> > if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
> > - (CPUFREQ_NAME_LEN + 2)))
> > break;
> > - i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
> > + i += sysfs_emit_at(buf, i, "%s ", t->name);
> > }
> > mutex_unlock(&cpufreq_governor_mutex);
> > out:
> > - i += sprintf(&buf[i], "\n");
> > + i += sysfs_emit_at(buf, i, "\n");
> > return i;
> > }
> >
> > @@ -895,7 +894,7 @@ ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
> > unsigned int cpu;
> >
> > for_each_cpu(cpu, mask) {
> > - i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u ", cpu);
> > + i += sysfs_emit_at(buf, i, "%u ", cpu);
> > if (i >= (PAGE_SIZE - 5))
> > break;
> > }
> > @@ -903,7 +902,7 @@ ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
> > /* Remove the extra space at the end */
> > i--;
> >
> > - i += sprintf(&buf[i], "\n");
> > + i += sysfs_emit_at(buf, i, "\n");
> > return i;
> > }
> > EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
> > @@ -946,7 +945,7 @@ static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
> > static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
> > {
> > if (!policy->governor || !policy->governor->show_setspeed)
> > - return sprintf(buf, "<unsupported>\n");
> > + return sysfs_emit(buf, "<unsupported>\n");
> >
> > return policy->governor->show_setspeed(policy, buf);
> > }
> > @@ -960,8 +959,8 @@ static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
> > int ret;
> > ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
> > if (!ret)
> > - return sprintf(buf, "%u\n", limit);
> > - return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
> > + return sysfs_emit(buf, "%u\n", limit);
> > + return sysfs_emit(buf, "%u\n", policy->cpuinfo.max_freq);
> > }
> >
> > cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
>
>
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