From: Len Brown <len.brown@intel.com>
Date: Tue, 28 Sep 2010 20:50:50 +0000 (-0400)
Subject: ACPI: acpi_pad: simplify code to avoid false gcc build warning
X-Git-Tag: v2.6.36-rc7~25^2^8~2
X-Git-Url: http://bbs.cooldavid.org/git/?a=commitdiff_plain;h=c9ad8e062e4c733b36fc10ebc201bedde1a4da80;p=net-next-2.6.git

ACPI: acpi_pad: simplify code to avoid false gcc build warning

acpi_pad.c:432: warning: ‘num_cpus’ may be used uninitialized in this function

gcc 4.4.4 was unable to notice that num_cpus is always set.
Re-arrange the code to un-confuse gcc, and also make
it easier for humans to read....

Signed-off-by: Len Brown <len.browns@intel.com>
---

diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
index b76848c80be..6b115f6c431 100644
--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c
@@ -382,31 +382,32 @@ static void acpi_pad_remove_sysfs(struct acpi_device *device)
 	device_remove_file(&device->dev, &dev_attr_rrtime);
 }
 
-/* Query firmware how many CPUs should be idle */
-static int acpi_pad_pur(acpi_handle handle, int *num_cpus)
+/*
+ * Query firmware how many CPUs should be idle
+ * return -1 on failure
+ */
+static int acpi_pad_pur(acpi_handle handle)
 {
 	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 	union acpi_object *package;
-	int rev, num, ret = -EINVAL;
+	int num = -1;
 
 	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
-		return -EINVAL;
+		return num;
 
 	if (!buffer.length || !buffer.pointer)
-		return -EINVAL;
+		return num;
 
 	package = buffer.pointer;
-	if (package->type != ACPI_TYPE_PACKAGE || package->package.count != 2)
-		goto out;
-	rev = package->package.elements[0].integer.value;
-	num = package->package.elements[1].integer.value;
-	if (rev != 1 || num < 0)
-		goto out;
-	*num_cpus = num;
-	ret = 0;
-out:
+
+	if (package->type == ACPI_TYPE_PACKAGE &&
+		package->package.count == 2 &&
+		package->package.elements[0].integer.value == 1) /* rev 1 */
+
+		num = package->package.elements[1].integer.value;
+
 	kfree(buffer.pointer);
-	return ret;
+	return num;
 }
 
 /* Notify firmware how many CPUs are idle */
@@ -433,7 +434,8 @@ static void acpi_pad_handle_notify(acpi_handle handle)
 	uint32_t idle_cpus;
 
 	mutex_lock(&isolated_cpus_lock);
-	if (acpi_pad_pur(handle, &num_cpus)) {
+	num_cpus = acpi_pad_pur(handle);
+	if (num_cpus < 0) {
 		mutex_unlock(&isolated_cpus_lock);
 		return;
 	}