The patch titled
Subject: lib: bitmap: change bitmap_shift_right to take unsigned parameters
has been added to the -mm tree. Its filename is
lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters.patch
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From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Subject: lib: bitmap: change bitmap_shift_right to take unsigned parameters
I've previously changed the nbits parameter of most bitmap_* functions to
unsigned; now it is bitmap_shift_{left,right}'s turn. This alone saves
some .text, but while at it I found that there were a few other things one
could do. The end result of these seven patches is
$ scripts/bloat-o-meter /tmp/bitmap.o.{old,new}
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-328 (-328)
function old new delta
__bitmap_shift_right 384 226 -158
__bitmap_shift_left 306 136 -170
and less importantly also a smaller stack footprint
$ stack-o-meter.pl master bitmap
file function old new delta
lib/bitmap.o __bitmap_shift_right 24 8 -16
lib/bitmap.o __bitmap_shift_left 24 0 -24
For each pair of 0 <= shift <= nbits <= 256 I've tested the end result
with a few randomly filled src buffers (including garbage beyond nbits),
in each case verifying that the shift {left,right}-most bits of dst are
zero and the remaining nbits-shift bits correspond to src, so I'm fairly
confident I didn't screw up. That hasn't stopped me from being wrong
before, though.
This patch (of 7):
gcc can generate slightly better code for stuff like "nbits %
BITS_PER_LONG" when it knows nbits is not negative. Since negative size
bitmaps or shift amounts don't make sense, change these parameters of
bitmap_shift_right to unsigned.
The expressions involving "lim - 1" are still ok, since if lim is 0 the
loop is never executed.
Also use "shift" and "nbits" consistently for the parameter names.
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/bitmap.h | 12 ++++++------
lib/bitmap.c | 10 +++++-----
2 files changed, 11 insertions(+), 11 deletions(-)
diff -puN include/linux/bitmap.h~lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters include/linux/bitmap.h
--- a/include/linux/bitmap.h~lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters
+++ a/include/linux/bitmap.h
@@ -96,8 +96,8 @@ extern int __bitmap_equal(const unsigned
const unsigned long *bitmap2, unsigned int nbits);
extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
unsigned int nbits);
-extern void __bitmap_shift_right(unsigned long *dst,
- const unsigned long *src, int shift, int bits);
+extern void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
+ unsigned int shift, unsigned int nbits);
extern void __bitmap_shift_left(unsigned long *dst,
const unsigned long *src, int shift, int bits);
extern int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
@@ -313,13 +313,13 @@ static inline int bitmap_weight(const un
return __bitmap_weight(src, nbits);
}
-static inline void bitmap_shift_right(unsigned long *dst,
- const unsigned long *src, int n, int nbits)
+static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
+ unsigned int shift, int nbits)
{
if (small_const_nbits(nbits))
- *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> n;
+ *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
else
- __bitmap_shift_right(dst, src, n, nbits);
+ __bitmap_shift_right(dst, src, shift, nbits);
}
static inline void bitmap_shift_left(unsigned long *dst,
diff -puN lib/bitmap.c~lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters lib/bitmap.c
--- a/lib/bitmap.c~lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters
+++ a/lib/bitmap.c
@@ -104,17 +104,17 @@ EXPORT_SYMBOL(__bitmap_complement);
* @dst : destination bitmap
* @src : source bitmap
* @shift : shift by this many bits
- * @bits : bitmap size, in bits
+ * @nbits : bitmap size, in bits
*
* Shifting right (dividing) means moving bits in the MS -> LS bit
* direction. Zeros are fed into the vacated MS positions and the
* LS bits shifted off the bottom are lost.
*/
-void __bitmap_shift_right(unsigned long *dst,
- const unsigned long *src, int shift, int bits)
+void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
+ unsigned shift, unsigned nbits)
{
- int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
- int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
+ unsigned k, lim = BITS_TO_LONGS(nbits), left = nbits % BITS_PER_LONG;
+ unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
unsigned long mask = (1UL << left) - 1;
for (k = 0; off + k < lim; ++k) {
unsigned long upper, lower;
_
Patches currently in -mm which might be from linux@xxxxxxxxxxxxxxxxxx are
lib-string_get_size-remove-redundant-prefixes.patch
lib-string_get_size-use-32-bit-arithmetic-when-possible.patch
lib-string_get_size-return-void.patch
lib-bitmap-more-signed-unsigned-conversions.patch
linux-nodemaskh-update-bitmap-wrappers-to-take-unsigned-int.patch
linux-cpumaskh-update-bitmap-wrappers-to-take-unsigned-int.patch
lib-bitmap-update-bitmap_onto-to-unsigned.patch
lib-bitmap-update-bitmap_onto-to-unsigned-checkpatch-fixes.patch
lib-bitmap-change-parameters-of-bitmap_fold-to-unsigned.patch
lib-bitmap-simplify-bitmap_pos_to_ord.patch
lib-bitmap-simplify-bitmap_ord_to_pos.patch
lib-bitmap-make-the-bits-parameter-of-bitmap_remap-unsigned.patch
lib-remove-strnicmp.patch
lib-interval_treec-simplify-includes.patch
lib-sortc-use-simpler-includes.patch
lib-dynamic_queue_limitsc-simplify-includes.patch
lib-halfmd4c-simplify-includes.patch
lib-idrc-remove-redundant-include.patch
lib-genallocc-remove-redundant-include.patch
lib-list_sortc-rearrange-includes.patch
lib-md5c-simplify-include.patch
lib-llistc-remove-redundant-include.patch
lib-kobject_ueventc-remove-redundant-include.patch
lib-nlattrc-remove-redundant-include.patch
lib-plistc-remove-redundant-include.patch
lib-radix-treec-change-to-simpler-include.patch
lib-show_memc-remove-redundant-include.patch
lib-sortc-move-include-inside-if-0.patch
lib-stmp_devicec-replace-moduleh-include.patch
lib-strncpy_from_userc-replace-moduleh-include.patch
lib-percpu_idac-remove-redundant-includes.patch
lib-lcmc-replace-include.patch
lib-bitmapc-change-prototype-of-bitmap_copy_le.patch
lib-bitmapc-elide-bitmap_copy_le-on-little-endian.patch
lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters.patch
lib-bitmap-eliminate-branch-in-__bitmap_shift_right.patch
lib-bitmap-remove-redundant-code-from-__bitmap_shift_right.patch
lib-bitmap-yet-another-simplification-in-__bitmap_shift_right.patch
lib-bitmap-change-bitmap_shift_left-to-take-unsigned-parameters.patch
lib-bitmap-eliminate-branch-in-__bitmap_shift_left.patch
lib-bitmap-remove-redundant-code-from-__bitmap_shift_left.patch
checkpatch-emit-an-error-when-using-predefined-timestamp-macros.patch
linux-next.patch
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