1 files changed, 17 insertions, 25 deletions

diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 4437c70c7c2b..952fbc2d4abc 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -28,29 +28,27 @@
 
 static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
-/*
- * SMT snooze delay stuff, 64-bit only for now
- */
-
 #ifdef CONFIG_PPC64
 
-/* Time in microseconds we delay before sleeping in the idle loop */
-static DEFINE_PER_CPU(long, smt_snooze_delay) = { 100 };
+/*
+ * Snooze delay has not been hooked up since 3fa8cad82b94 ("powerpc/pseries/cpuidle:
+ * smt-snooze-delay cleanup.") and has been broken even longer. As was foretold in
+ * 2014:
+ *
+ *  "ppc64_util currently utilises it. Once we fix ppc64_util, propose to clean
+ *  up the kernel code."
+ *
+ * powerpc-utils stopped using it as of 1.3.8. At some point in the future this
+ * code should be removed.
+ */
 
 static ssize_t store_smt_snooze_delay(struct device *dev,
 				      struct device_attribute *attr,
 				      const char *buf,
 				      size_t count)
 {
-	struct cpu *cpu = container_of(dev, struct cpu, dev);
-	ssize_t ret;
-	long snooze;
-
-	ret = sscanf(buf, "%ld", &snooze);
-	if (ret != 1)
-		return -EINVAL;
-
-	per_cpu(smt_snooze_delay, cpu->dev.id) = snooze;
+	pr_warn_once("%s (%d) stored to unsupported smt_snooze_delay, which has no effect.\n",
+		     current->comm, current->pid);
 	return count;
 }
 
@@ -58,9 +56,9 @@ static ssize_t show_smt_snooze_delay(struct device *dev,
 				     struct device_attribute *attr,
 				     char *buf)
 {
-	struct cpu *cpu = container_of(dev, struct cpu, dev);
-
-	return sprintf(buf, "%ld\n", per_cpu(smt_snooze_delay, cpu->dev.id));
+	pr_warn_once("%s (%d) read from unsupported smt_snooze_delay\n",
+		     current->comm, current->pid);
+	return sprintf(buf, "100\n");
 }
 
 static DEVICE_ATTR(smt_snooze_delay, 0644, show_smt_snooze_delay,
@@ -68,16 +66,10 @@ static DEVICE_ATTR(smt_snooze_delay, 0644, show_smt_snooze_delay,
 
 static int __init setup_smt_snooze_delay(char *str)
 {
-	unsigned int cpu;
-	long snooze;
-
 	if (!cpu_has_feature(CPU_FTR_SMT))
 		return 1;
 
-	snooze = simple_strtol(str, NULL, 10);
-	for_each_possible_cpu(cpu)
-		per_cpu(smt_snooze_delay, cpu) = snooze;
-
+	pr_warn("smt-snooze-delay command line option has no effect\n");
 	return 1;
 }
 __setup("smt-snooze-delay=", setup_smt_snooze_delay);