lib: bitmap: yet another simplification in __bitmap_shift_right

If left is 0, we can just let mask be ~0UL, so that anding with it is a
no-op.  Conveniently, BITMAP_LAST_WORD_MASK provides precisely what we
need, and we can eliminate left.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 761d2d4..db88512 100644 (file)
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -113,9 +113,9 @@ EXPORT_SYMBOL(__bitmap_complement);
 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
                        unsigned shift, unsigned nbits)
 {
-       unsigned k, lim = BITS_TO_LONGS(nbits), left = nbits % BITS_PER_LONG;
+       unsigned k, lim = BITS_TO_LONGS(nbits);
        unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
-       unsigned long mask = (1UL << left) - 1;
+       unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
        for (k = 0; off + k < lim; ++k) {
                unsigned long upper, lower;
 
@@ -127,12 +127,12 @@ void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
                        upper = 0;
                else {
                        upper = src[off + k + 1];
-                       if (off + k + 1 == lim - 1 && left)
+                       if (off + k + 1 == lim - 1)
                                upper &= mask;
                        upper <<= (BITS_PER_LONG - rem);
                }
                lower = src[off + k];
-               if (left && off + k == lim - 1)
+               if (off + k == lim - 1)
                        lower &= mask;
                lower >>= rem;
                dst[k] = lower | upper;