diff mbox series

[06/12] tools: sync small_const_nbits() macro with the kernel

Message ID 20210321215457.588554-7-yury.norov@gmail.com (mailing list archive)
State New
Headers show
Series lib/find_bit: fast path for small bitmaps | expand

Commit Message

Yury Norov March 21, 2021, 9:54 p.m. UTC
Move the macro from tools/include/asm-generic/bitsperlong.h
to tools/include/linux/bitmap.h

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
 tools/include/asm-generic/bitsperlong.h | 3 +++
 tools/include/linux/bitmap.h            | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)

Comments

Rasmus Villemoes March 22, 2021, 8:34 a.m. UTC | #1
On 21/03/2021 22.54, Yury Norov wrote:
> Move the macro from tools/include/asm-generic/bitsperlong.h
> to tools/include/linux/bitmap.h

The patch does it the other way around :)

> Signed-off-by: Yury Norov <yury.norov@gmail.com>
> ---
>  tools/include/asm-generic/bitsperlong.h | 3 +++
>  tools/include/linux/bitmap.h            | 3 ---
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/include/asm-generic/bitsperlong.h b/tools/include/asm-generic/bitsperlong.h
> index 8f2283052333..f530da2506cc 100644
> --- a/tools/include/asm-generic/bitsperlong.h
> +++ b/tools/include/asm-generic/bitsperlong.h
> @@ -18,4 +18,7 @@
>  #define BITS_PER_LONG_LONG 64
>  #endif
>  
> +#define small_const_nbits(nbits) \
> +	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
> +

Well, the movement is consistent with the kernel, but shouldn't the
definition also be updated to exclude constant-zero-size? It's not that
they exist or ever have, in tools/ or kernel proper, but just if some
day some oddball CONFIG_ combination ends up creating such a beast, I'd
rather not have code like

+	if (small_const_nbits(size)) {
+		unsigned long val = *addr & GENMASK(size - 1, 0);

blow up at run-time.

Other than that (and the above commit log typo), consider the series

Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Yury Norov March 24, 2021, 7:49 p.m. UTC | #2
On Mon, Mar 22, 2021 at 09:34:47AM +0100, Rasmus Villemoes wrote:
> On 21/03/2021 22.54, Yury Norov wrote:
> > Move the macro from tools/include/asm-generic/bitsperlong.h
> > to tools/include/linux/bitmap.h
> 
> The patch does it the other way around :)
> 
> > Signed-off-by: Yury Norov <yury.norov@gmail.com>
> > ---
> >  tools/include/asm-generic/bitsperlong.h | 3 +++
> >  tools/include/linux/bitmap.h            | 3 ---
> >  2 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/include/asm-generic/bitsperlong.h b/tools/include/asm-generic/bitsperlong.h
> > index 8f2283052333..f530da2506cc 100644
> > --- a/tools/include/asm-generic/bitsperlong.h
> > +++ b/tools/include/asm-generic/bitsperlong.h
> > @@ -18,4 +18,7 @@
> >  #define BITS_PER_LONG_LONG 64
> >  #endif
> >  
> > +#define small_const_nbits(nbits) \
> > +	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
> > +
> 
> Well, the movement is consistent with the kernel, but shouldn't the
> definition also be updated to exclude constant-zero-size? It's not that
> they exist or ever have, in tools/ or kernel proper, but just if some
> day some oddball CONFIG_ combination ends up creating such a beast, I'd
> rather not have code like
> 
> +	if (small_const_nbits(size)) {
> +		unsigned long val = *addr & GENMASK(size - 1, 0);
> 
> blow up at run-time.
> 
> Other than that (and the above commit log typo), consider the series
> 
> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

Thanks for spotting out this. The proper version of the patch is
below.

Andrew, it seems everything else looks good. If so, should I resubmit
the series, or you can pull it as is, including this patch?

Thanks,
Yury

From 7558697d4448f01a8ef73cd31def5d3e68b44b61 Mon Sep 17 00:00:00 2001
From: Yury Norov <yury.norov@gmail.com>
Date: Wed, 17 Feb 2021 20:05:05 -0800
Subject: [PATCH] tools: sync small_const_nbits() macro with the kernel

Sync implementation with the kernel and move the macro from
tools/include/linux/bitmap.h to tools/include/asm-generic/bitsperlong.h

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
 tools/include/asm-generic/bitsperlong.h | 3 +++
 tools/include/linux/bitmap.h            | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/include/asm-generic/bitsperlong.h b/tools/include/asm-generic/bitsperlong.h
index 8f2283052333..2093d56ddd11 100644
--- a/tools/include/asm-generic/bitsperlong.h
+++ b/tools/include/asm-generic/bitsperlong.h
@@ -18,4 +18,7 @@
 #define BITS_PER_LONG_LONG 64
 #endif
 
+#define small_const_nbits(nbits) \
+	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)
+
 #endif /* __ASM_GENERIC_BITS_PER_LONG */
diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h
index 4aabc23ec747..330dbf7509cc 100644
--- a/tools/include/linux/bitmap.h
+++ b/tools/include/linux/bitmap.h
@@ -22,9 +22,6 @@ void bitmap_clear(unsigned long *map, unsigned int start, int len);
 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
 
-#define small_const_nbits(nbits) \
-	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
-
 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 {
 	if (small_const_nbits(nbits))
diff mbox series

Patch

diff --git a/tools/include/asm-generic/bitsperlong.h b/tools/include/asm-generic/bitsperlong.h
index 8f2283052333..f530da2506cc 100644
--- a/tools/include/asm-generic/bitsperlong.h
+++ b/tools/include/asm-generic/bitsperlong.h
@@ -18,4 +18,7 @@ 
 #define BITS_PER_LONG_LONG 64
 #endif
 
+#define small_const_nbits(nbits) \
+	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
+
 #endif /* __ASM_GENERIC_BITS_PER_LONG */
diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h
index 4aabc23ec747..330dbf7509cc 100644
--- a/tools/include/linux/bitmap.h
+++ b/tools/include/linux/bitmap.h
@@ -22,9 +22,6 @@  void bitmap_clear(unsigned long *map, unsigned int start, int len);
 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
 
-#define small_const_nbits(nbits) \
-	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
-
 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
 {
 	if (small_const_nbits(nbits))