diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index acf5e8d..29fc933 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -28,8 +28,8 @@
  * The available bitmap operations and their rough meaning in the
  * case that the bitmap is a single unsigned long are thus:
  *
- * Note that nbits should be always a compile time evaluable constant.
- * Otherwise many inlines will generate horrible code.
+ * The generated code is more efficient when nbits is known at
+ * compile-time and at most BITS_PER_LONG.
  *
  * ::
  *
@@ -120,6 +120,10 @@
 extern int __bitmap_full(const unsigned long *bitmap, unsigned int nbits);
 extern int __bitmap_equal(const unsigned long *bitmap1,
 			  const unsigned long *bitmap2, unsigned int nbits);
+extern bool __pure __bitmap_or_equal(const unsigned long *src1,
+				     const unsigned long *src2,
+				     const unsigned long *src3,
+				     unsigned int nbits);
 extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
 			unsigned int nbits);
 extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
@@ -204,38 +208,31 @@
 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
 
+/*
+ * The static inlines below do not handle constant nbits==0 correctly,
+ * so make such users (should any ever turn up) call the out-of-line
+ * versions.
+ */
 #define small_const_nbits(nbits) \
-	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
+	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)
 
 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 {
-	if (small_const_nbits(nbits))
-		*dst = 0UL;
-	else {
-		unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
-		memset(dst, 0, len);
-	}
+	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+	memset(dst, 0, len);
 }
 
 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 {
-	if (small_const_nbits(nbits))
-		*dst = ~0UL;
-	else {
-		unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
-		memset(dst, 0xff, len);
-	}
+	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+	memset(dst, 0xff, len);
 }
 
 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
 			unsigned int nbits)
 {
-	if (small_const_nbits(nbits))
-		*dst = *src;
-	else {
-		unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
-		memcpy(dst, src, len);
-	}
+	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+	memcpy(dst, src, len);
 }
 
 /*
@@ -328,6 +325,26 @@
 	return __bitmap_equal(src1, src2, nbits);
 }
 
+/**
+ * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third
+ * @src1:	Pointer to bitmap 1
+ * @src2:	Pointer to bitmap 2 will be or'ed with bitmap 1
+ * @src3:	Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
+ * @nbits:	number of bits in each of these bitmaps
+ *
+ * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
+ */
+static inline bool bitmap_or_equal(const unsigned long *src1,
+				   const unsigned long *src2,
+				   const unsigned long *src3,
+				   unsigned int nbits)
+{
+	if (!small_const_nbits(nbits))
+		return __bitmap_or_equal(src1, src2, src3, nbits);
+
+	return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
+}
+
 static inline int bitmap_intersects(const unsigned long *src1,
 			const unsigned long *src2, unsigned int nbits)
 {
@@ -398,7 +415,7 @@
 }
 
 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
-				unsigned int shift, int nbits)
+				unsigned int shift, unsigned int nbits)
 {
 	if (small_const_nbits(nbits))
 		*dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;