Merge branch 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

Pull percpu update from Tejun Heo:
 "This includes just one patch to reject non-power-of-2 alignments and
  trigger warning. Interestingly, this actually caught a bug in XEN
  ARM64"

* 'for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: ensure the requested alignment is power of two

include/linux/kernel.h

@@ -45,6 +45,7 @@
 
 #define REPEAT_BYTE(x)	((~0ul / 0xff) * (x))
 
+/* @a is a power of 2 value */
 #define ALIGN(x, a)		__ALIGN_KERNEL((x), (a))
 #define __ALIGN_MASK(x, mask)	__ALIGN_KERNEL_MASK((x), (mask))
 #define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))

mm/percpu.c

@@ -886,7 +886,8 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
 
 	size = ALIGN(size, 2);
 
-	if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
+	if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE ||
+		     !is_power_of_2(align))) {
 		WARN(true, "illegal size (%zu) or align (%zu) for percpu allocation\n",
 		     size, align);
 		return NULL;