powercap: Replace sprintf() with sysfs_emit() in sysfs show functions

Replace all sprintf() calls with sysfs_emit() in sysfs show functions. sysfs_emit() is preferred over sprintf() for formatting sysfs output as it provides better bounds checking and prevents potential buffer overflows.
Also, replace sprintf() with sysfs_emit() in show_constraint_name() and simplify the code by removing the redundant strlen() call since sysfs_emit() returns the length.

Signed-off-by Sumeet Pawnikar <[email protected]>

---
 drivers/powercap/powercap_sys.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

drivers/powercap/powercap_sys.c +5 -6

index 1ff369880beb..f3b2ae635305 100644
@@ -27,7 +27,7 @@ static ssize_t _attr##_show(struct device *dev, \
        \
        if (power_zone->ops->get_##_attr) { \
                if (!power_zone->ops->get_##_attr(power_zone, &value)) \
-                       len = sprintf(buf, "%lld\n", value); \
+                       len = sysfs_emit(buf, "%lld\n", value); \
        } \
        \
        return len; \

@@ -75,7 +75,7 @@ static ssize_t show_constraint_##_attr(struct device *dev, \
        pconst = &power_zone->constraints[id]; \
        if (pconst && pconst->ops && pconst->ops->get_##_attr) { \
                if (!pconst->ops->get_##_attr(power_zone, id, &value)) \
-                       len = sprintf(buf, "%lld\n", value); \
+                       len = sysfs_emit(buf, "%lld\n", value); \
        } \
        \
        return len; \

@@ -171,9 +171,8 @@ static ssize_t show_constraint_name(struct device *dev,
        if (pconst && pconst->ops && pconst->ops->get_name) {
                name = pconst->ops->get_name(power_zone, id);
                if (name) {
-                       sprintf(buf, "%.*s\n", POWERCAP_CONSTRAINT_NAME_LEN - 1,
-                               name);
-                       len = strlen(buf);
+                       len = sysfs_emit(buf, "%.*s\n",
+                                        POWERCAP_CONSTRAINT_NAME_LEN - 1, name);
                }
        }
 

@@ -350,7 +349,7 @@ static ssize_t name_show(struct device *dev,
 {
        struct powercap_zone *power_zone = to_powercap_zone(dev);
 
-       return sprintf(buf, "%s\n", power_zone->name);
+       return sysfs_emit(buf, "%s\n", power_zone->name);
 }
 
 static DEVICE_ATTR_RO(name);