bitmap_from_arr64

Signed-off-by: Yury Norov <yury.norov@gmail.com>

include/linux/bitmap.h

@@ -275,6 +275,13 @@ static inline void bitmap_copy_clear_tail(unsigned long *dst,
  * therefore conversion is not needed when copying data from/to arrays of u32.
  */
 #if BITS_PER_LONG == 64
+#define bitmap_from_arr64(bitmap, buf, nbits)			\
+	bitmap_copy_clear_tail((unsigned long *) (bitmap),	\
+			(const unsigned long *) (buf), (nbits))
+#define bitmap_to_arr64(buf, bitmap, nbits)			\
+	bitmap_copy_clear_tail((unsigned long *) (buf),		\
+			(const unsigned long *) (bitmap), (nbits))
+
 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
 							unsigned int nbits);
 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
@@ -286,6 +293,11 @@ void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
 #define bitmap_to_arr32(buf, bitmap, nbits)			\
 	bitmap_copy_clear_tail((unsigned long *) (buf),		\
 			(const unsigned long *) (bitmap), (nbits))
+
+void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf,
+							unsigned int nbits);
+void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap,
+							unsigned int nbits);
 #endif
 
 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,

lib/bitmap.c

@@ -1533,5 +1533,50 @@ void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
 		buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
 }
 EXPORT_SYMBOL(bitmap_to_arr32);
+#else /* BITS_PER_LONG == 32 */
+/**
+ * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap
+ *	@bitmap: array of unsigned longs, the destination bitmap
+ *	@buf: array of u64 (in host byte order), the source bitmap
+ *	@nbits: number of bits in @bitmap
+ */
+void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)
+{
+	while (nbits > 0) {
+		u64 val = *buf++;
+
+		*bitmap++ = (unsigned long)val;
+		if (nbits > 32)
+			*bitmap++ = (unsigned long)(val >> 32);
+		nbits -= 64;
+	}
+
+	/* Clear tail bits in last word beyond nbits. */
+	if (nbits % BITS_PER_LONG)
+		bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);
+}
+EXPORT_SYMBOL(bitmap_from_arr64);
+
+/**
+ * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits
+ *	@buf: array of u64 (in host byte order), the dest bitmap
+ *	@bitmap: array of unsigned longs, the source bitmap
+ *	@nbits: number of bits in @bitmap
+ */
+void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
+{
+	unsigned int i = 0, words = BITS_TO_LONGS(nbits);
+
+	while (i < words) {
+		buf[i/2] = bitmap[i++];
+		if (i < words)
+			buf[i/2] |= bitmap[i++] << 32;
+	}
+
+	/* Clear tail bits in last element of array beyond nbits. */
+	if (nbits % 64)
+		buf[i - 1] &= GENMASK_ULL(nbits, 0);
+}
+EXPORT_SYMBOL(bitmap_to_arr64);
 
 #endif