mm/vmalloc: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

@@ -358,7 +358,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	struct vmap_area *first;
 
 	BUG_ON(!size);
-	BUG_ON(size & ~PAGE_MASK);
+	BUG_ON(offset_in_page(size));
 	BUG_ON(!is_power_of_2(align));
 
 	va = kmalloc_node(sizeof(struct vmap_area),
@@ -936,7 +936,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
 	void *vaddr = NULL;
 	unsigned int order;
 
-	BUG_ON(size & ~PAGE_MASK);
+	BUG_ON(offset_in_page(size));
 	BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
 	if (WARN_ON(size == 0)) {
 		/*
@@ -989,7 +989,7 @@ static void vb_free(const void *addr, unsigned long size)
 	unsigned int order;
 	struct vmap_block *vb;
 
-	BUG_ON(size & ~PAGE_MASK);
+	BUG_ON(offset_in_page(size));
 	BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
 
 	flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
@@ -1902,7 +1902,7 @@ static int aligned_vread(char *buf, char *addr, unsigned long count)
 	while (count) {
 		unsigned long offset, length;
 
-		offset = (unsigned long)addr & ~PAGE_MASK;
+		offset = offset_in_page(addr);
 		length = PAGE_SIZE - offset;
 		if (length > count)
 			length = count;
@@ -1941,7 +1941,7 @@ static int aligned_vwrite(char *buf, char *addr, unsigned long count)
 	while (count) {
 		unsigned long offset, length;
 
-		offset = (unsigned long)addr & ~PAGE_MASK;
+		offset = offset_in_page(addr);
 		length = PAGE_SIZE - offset;
 		if (length > count)
 			length = count;
@@ -2392,7 +2392,7 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
 	bool purged = false;
 
 	/* verify parameters and allocate data structures */
-	BUG_ON(align & ~PAGE_MASK || !is_power_of_2(align));
+	BUG_ON(offset_in_page(align) || !is_power_of_2(align));
 	for (last_area = 0, area = 0; area < nr_vms; area++) {
 		start = offsets[area];
 		end = start + sizes[area];