1 files changed, 10 insertions, 5 deletions

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index e43533ec7660..d9bf699e0e7a 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -67,6 +67,11 @@
  *  bitmap_from_arr32(dst, buf, nbits)          Copy nbits from u32[] buf to dst
  *  bitmap_to_arr32(buf, src, nbits)            Copy nbits from buf to u32[] dst
  *
+ * Note, bitmap_zero() and bitmap_fill() operate over the region of
+ * unsigned longs, that is, bits behind bitmap till the unsigned long
+ * boundary will be zeroed or filled as well. Consider to use
+ * bitmap_clear() or bitmap_set() to make explicit zeroing or filling
+ * respectively.
  */
 
 /**
@@ -202,12 +207,12 @@ static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 
 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 {
-        unsigned int nlongs = BITS_TO_LONGS(nbits);
-        if (!small_const_nbits(nbits)) {
-                unsigned int len = (nlongs - 1) * sizeof(unsigned long);
-                memset(dst, 0xff,  len);
+        if (small_const_nbits(nbits))
+                *dst = ~0UL;
+        else {
+                unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+                memset(dst, 0xff, len);
         }
-        dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
 }
 
 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,