Re: Yet more ARM breakage in linux-next

From: Rusty Russell
Date: Wed Dec 03 2008 - 18:23:00 EST

On Thursday 04 December 2008 07:11:09 Andrew Morton wrote:
> On Wed, 3 Dec 2008 19:29:05 +0000
> Russell King <rmk+lkml@xxxxxxxxxxxxxxxx> wrote:
> > This seems to be causing lots of ARM breakage:
> >
> > lib/find_next_bit.c:183: error: implicit declaration of function '__fls'
> >
> > Whoever's responsible,
> git-blame?

It's me. Turns out sparc, avr32 and arm all don't define __fls in their
asm/bitops.h, and I'm the first one to use it in generic code.

But as I prepared this patch, I note that the armv5 __fls/fls is wrong:

/* Implement fls() in C so that 64-bit args are suitably truncated */
static inline int fls(int x)
return __fls(x);

__fls(x) returns a bit number (0-31). fls() returns 0 or bitnumber+1.

(Yes, classic useless kerneldoc documentation doesn't actually *say*
this clearly).

But here's the linux-next fix:

arm: define __fls for pre v5 ARM

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h
--- a/arch/arm/include/asm/bitops.h
+++ b/arch/arm/include/asm/bitops.h
@@ -239,6 +239,7 @@ extern int _find_next_bit_be(const unsig
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/__ffs.h>
#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/ffs.h>


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at