cpuidle: sysfs: Use sysfs_emit()/sysfs_emit_at() instead of sprintf()/scnprintf()

The ->show() callbacks in sysfs should use sysfs_emit() or
sysfs_emit_at() when formatting values for user space.

These helpers are the recommended way to ensure correct buffer
handling and consistency across the kernel.

See Documentation/filesystems/sysfs.rst for details.

No functional change intended.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Vivek Yadav <vivekyadav1207731111@gmail.com>
Link: https://patch.msgid.link/20250919165657.233349-1-vivekyadav1207731111@gmail.com
[ rjw: Minor subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: viveky1794

drivers/cpuidle/sysfs.c

@@ -27,14 +27,14 @@ static ssize_t show_available_governors(struct device *dev,
 
 	mutex_lock(&cpuidle_lock);
 	list_for_each_entry(tmp, &cpuidle_governors, governor_list) {
-		if (i >= (ssize_t) (PAGE_SIZE - (CPUIDLE_NAME_LEN + 2)))
+		if (i >= (ssize_t)(PAGE_SIZE - (CPUIDLE_NAME_LEN + 2)))
 			goto out;
 
-		i += scnprintf(&buf[i], CPUIDLE_NAME_LEN + 1, "%s ", tmp->name);
+		i += sysfs_emit_at(buf, i, "%.*s ", CPUIDLE_NAME_LEN, tmp->name);
 	}
 
 out:
-	i+= sprintf(&buf[i], "\n");
+	i += sysfs_emit_at(buf, i, "\n");
 	mutex_unlock(&cpuidle_lock);
 	return i;
 }
@@ -49,9 +49,9 @@ static ssize_t show_current_driver(struct device *dev,
 	spin_lock(&cpuidle_driver_lock);
 	drv = cpuidle_get_driver();
 	if (drv)
-		ret = sprintf(buf, "%s\n", drv->name);
+		ret = sysfs_emit(buf, "%s\n", drv->name);
 	else
-		ret = sprintf(buf, "none\n");
+		ret = sysfs_emit(buf, "none\n");
 	spin_unlock(&cpuidle_driver_lock);
 
 	return ret;
@@ -65,9 +65,9 @@ static ssize_t show_current_governor(struct device *dev,
 
 	mutex_lock(&cpuidle_lock);
 	if (cpuidle_curr_governor)
-		ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name);
+		ret = sysfs_emit(buf, "%s\n", cpuidle_curr_governor->name);
 	else
-		ret = sprintf(buf, "none\n");
+		ret = sysfs_emit(buf, "none\n");
 	mutex_unlock(&cpuidle_lock);
 
 	return ret;
@@ -230,15 +230,15 @@ static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0644, show, store)
 static ssize_t show_state_##_name(struct cpuidle_state *state, \
 			 struct cpuidle_state_usage *state_usage, char *buf) \
 { \
-	return sprintf(buf, "%u\n", state->_name);\
+	return sysfs_emit(buf, "%u\n", state->_name);\
 }
 
 #define define_show_state_ull_function(_name) \
 static ssize_t show_state_##_name(struct cpuidle_state *state, \
 				  struct cpuidle_state_usage *state_usage, \
 				  char *buf)				\
 { \
-	return sprintf(buf, "%llu\n", state_usage->_name);\
+	return sysfs_emit(buf, "%llu\n", state_usage->_name);\
 }
 
 #define define_show_state_str_function(_name) \
@@ -247,16 +247,16 @@ static ssize_t show_state_##_name(struct cpuidle_state *state, \
 				  char *buf)				\
 { \
 	if (state->_name[0] == '\0')\
-		return sprintf(buf, "<null>\n");\
-	return sprintf(buf, "%s\n", state->_name);\
+		return sysfs_emit(buf, "<null>\n");\
+	return sysfs_emit(buf, "%s\n", state->_name);\
 }
 
 #define define_show_state_time_function(_name) \
 static ssize_t show_state_##_name(struct cpuidle_state *state, \
 				  struct cpuidle_state_usage *state_usage, \
 				  char *buf) \
 { \
-	return sprintf(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \
+	return sysfs_emit(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \
 }
 
 define_show_state_time_function(exit_latency)
@@ -273,14 +273,14 @@ static ssize_t show_state_time(struct cpuidle_state *state,
 			       struct cpuidle_state_usage *state_usage,
 			       char *buf)
 {
-	return sprintf(buf, "%llu\n", ktime_to_us(state_usage->time_ns));
+	return sysfs_emit(buf, "%llu\n", ktime_to_us(state_usage->time_ns));
 }
 
 static ssize_t show_state_disable(struct cpuidle_state *state,
 				  struct cpuidle_state_usage *state_usage,
 				  char *buf)
 {
-	return sprintf(buf, "%llu\n",
+	return sysfs_emit(buf, "%llu\n",
 		       state_usage->disable & CPUIDLE_STATE_DISABLED_BY_USER);
 }
 
@@ -310,7 +310,7 @@ static ssize_t show_state_default_status(struct cpuidle_state *state,
 					  struct cpuidle_state_usage *state_usage,
 					  char *buf)
 {
-	return sprintf(buf, "%s\n",
+	return sysfs_emit(buf, "%s\n",
 		       state->flags & CPUIDLE_FLAG_OFF ? "disabled" : "enabled");
 }
 
@@ -358,7 +358,7 @@ static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
 					 struct cpuidle_state_usage *state_usage, \
 					 char *buf)				\
 { \
-	return sprintf(buf, "%llu\n", state_usage->s2idle_##_name);\
+	return sysfs_emit(buf, "%llu\n", state_usage->s2idle_##_name);\
 }
 
 define_show_state_s2idle_ull_function(usage);
@@ -550,7 +550,7 @@ static ssize_t show_driver_name(struct cpuidle_driver *drv, char *buf)
 	ssize_t ret;
 
 	spin_lock(&cpuidle_driver_lock);
-	ret = sprintf(buf, "%s\n", drv ? drv->name : "none");
+	ret = sysfs_emit(buf, "%s\n", drv ? drv->name : "none");
 	spin_unlock(&cpuidle_driver_lock);
 
 	return ret;