mm/percpu: use offset_in_page macro

linux/mm.h provides offset_in_page() macro.  Let's use already predefined
macro instead of (addr & ~PAGE_MASK).

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/percpu.c

@@ -1554,12 +1554,12 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 	PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
 #ifdef CONFIG_SMP
 	PCPU_SETUP_BUG_ON(!ai->static_size);
-	PCPU_SETUP_BUG_ON((unsigned long)__per_cpu_start & ~PAGE_MASK);
+	PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start));
 #endif
 	PCPU_SETUP_BUG_ON(!base_addr);
-	PCPU_SETUP_BUG_ON((unsigned long)base_addr & ~PAGE_MASK);
+	PCPU_SETUP_BUG_ON(offset_in_page(base_addr));
 	PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
-	PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
+	PCPU_SETUP_BUG_ON(offset_in_page(ai->unit_size));
 	PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
 	PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
 	PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
@@ -1806,7 +1806,7 @@ static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
 
 	alloc_size = roundup(min_unit_size, atom_size);
 	upa = alloc_size / min_unit_size;
-	while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
+	while (alloc_size % upa || (offset_in_page(alloc_size / upa)))
 		upa--;
 	max_upa = upa;
 
@@ -1838,7 +1838,7 @@ static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
 	for (upa = max_upa; upa; upa--) {
 		int allocs = 0, wasted = 0;
 
-		if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
+		if (alloc_size % upa || (offset_in_page(alloc_size / upa)))
 			continue;
 
 		for (group = 0; group < nr_groups; group++) {