On Fri, Jan 29, 2021 at 10:49 PM Yury Norov <yury.norov@xxxxxxxxx> wrote:
Many algorithms become simplier if they are passed with relatively small
simpler
input values. One example is bitmap operations when the whole bitmap fits
into one word. To implement such simplifications, linux/bitmap.h declares
small_const_nbits() macro.
Other subsystems may also benefit from optimizations of this sort, like
find_bit API in the following patches. So it looks helpful to generalize
the macro and extend it's visibility.
It should probably go to linux/kernel.h, but doing that creates circular
dependencies. So put it in asm-generic/bitsperlong.h.
No, no, please leave kernel.h alone. It's already quite a mess.
And this shouldn't be in the commit message either.
...
- if (small_const_nbits(nbits))
+ if (SMALL_CONST(nbits - 1))
Not sure if we need to rename it.
...
--- a/include/linux/bits.h
+++ b/include/linux/bits.h
@@ -37,7 +37,7 @@
#define GENMASK(h, l) \
(GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
-#define BITS_FIRST(nr) GENMASK(nr), 0)
+#define BITS_FIRST(nr) GENMASK((nr), 0)
How come?!
...
diff --git a/tools/include/asm-generic/bitsperlong.h b/tools/include/asm-generic/bitsperlong.h
index 8f2283052333..432d272baf27 100644
--- a/tools/include/asm-generic/bitsperlong.h
+++ b/tools/include/asm-generic/bitsperlong.h
I think a tools update would be better to have in a separate patch.
--
With Best Regards,
Andy Shevchenko
