diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 8649c7b5f2b84e36f449b597cd48e0fc5018302d..99ca9251f502640dc9c1341add3f82a03f1f0eb3 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -54,14 +54,7 @@ __acquires(bitmap->lock)
 {
 	unsigned char *mappage;
 
-	if (page >= bitmap->pages) {
-		/* This can happen if bitmap_start_sync goes beyond
-		 * End-of-device while looking for a whole page.
-		 * It is harmless.
-		 */
-		return -EINVAL;
-	}
-
+	WARN_ON_ONCE(page >= bitmap->pages);
 	if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
 		return 0;
 
@@ -1405,20 +1398,25 @@ __acquires(bitmap->lock)
 	sector_t chunk = offset >> bitmap->chunkshift;
 	unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
 	unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
-	sector_t csize;
+	sector_t csize = ((sector_t)1) << bitmap->chunkshift;
 	int err;
 
-	if (page >= bitmap->pages)
+	if (page >= bitmap->pages) {
+		/*
+		 * This can happen if bitmap_start_sync goes beyond
+		 * End-of-device while looking for a whole page or
+		 * user set a huge number to sysfs bitmap_set_bits.
+		 */
+		*blocks = csize - (offset & (csize - 1));
 		return NULL;
-
+	}
 	err = md_bitmap_checkpage(bitmap, page, create, 0);
 
 	if (bitmap->bp[page].hijacked ||
 	    bitmap->bp[page].map == NULL)
 		csize = ((sector_t)1) << (bitmap->chunkshift +
 					  PAGE_COUNTER_SHIFT);
-	else
-		csize = ((sector_t)1) << bitmap->chunkshift;
+
 	*blocks = csize - (offset & (csize - 1));
 
 	if (err < 0)