lib/bitmap.c: simplify bitmap_pos_to_ord
authorRasmus Villemoes <linux@rasmusvillemoes.dk>
Thu, 12 Feb 2015 23:02:07 +0000 (15:02 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 13 Feb 2015 02:54:14 +0000 (18:54 -0800)
commitdf1d80a9eb16d98002673f68a7ebbe881f6e6946
tree354e5cd242fdd024e258f40460887d231d48e2aa
parentb26ad5836c3a0a9d456eb60b9f841ca15403ee59
lib/bitmap.c: simplify bitmap_pos_to_ord

The ordinal of a set bit is simply the number of set bits before it;
counting those doesn't need to be done one bit at a time.  While at it,
update the parameters to unsigned int.

It is not completely unthinkable that gcc would see pos as compile-time
constant 0 in one of the uses of bitmap_pos_to_ord.  Since the static
inline frontend bitmap_weight doesn't handle nbits==0 correctly (it would
behave exactly as if nbits==BITS_PER_LONG), use __bitmap_weight.

Alternatively, the last line could be spelled bitmap_weight(buf, pos+1)-1,
but this is simpler.

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>
lib/bitmap.c