[Patch 2 of 17] cpumask v4 - Dont generate nonzero unused bits in bitmap

[Paul Jackson <pj@sgi.com>]

mask2-bitmap-complement - Dont generate nonzero unused bits in bitmap
        Tighten up bitmap so it does not generate nonzero bits
        in the unused tail if it is not given any on input.

Index: 2.6.5.bitmap/lib/bitmap.c
===================================================================
--- 2.6.5.bitmap.orig/lib/bitmap.c	2004-04-05 02:50:25.000000000 -0700
+++ 2.6.5.bitmap/lib/bitmap.c	2004-04-05 03:02:39.000000000 -0700
@@ -26,10 +26,10 @@
  * carefully filter out these unused bits from impacting their
  * results.
  *
- * Except for bitmap_complement, these operations hold to a
- * slightly stronger rule: if you don't input any bitmaps to
- * these ops that have some unused bits set, then they won't
- * output any set unused bits in output bitmaps.
+ * These operations actually hold to a slightly stronger rule:
+ * if you don't input any bitmaps to these ops that have some
+ * unused bits set, then they won't output any set unused bits
+ * in output bitmaps.
  */
 
 #define MAX_BITMAP_BITS	512U	/* for ia64 NR_CPUS maximum */
@@ -83,11 +83,12 @@
 
 void bitmap_complement(unsigned long *bitmap, int bits)
 {
-	int k;
-	int nr = BITS_TO_LONGS(bits);
-
-	for (k = 0; k < nr; ++k)
+	int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
 		bitmap[k] = ~bitmap[k];
+
+	if (bits % BITS_PER_LONG)
+		bitmap[k] = ~bitmap[k] & ((1UL << (bits % BITS_PER_LONG)) - 1);
 }
 EXPORT_SYMBOL(bitmap_complement);
 


-- 
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                          Programmer, Linux Scalability
                          Paul Jackson <pj@sgi.com> 1.650.933.1373