On Monday 19 October 2015 11:37:00 Ralf Baechle wrote:

On Wed, Oct 07, 2015 at 01:23:07PM +0200, Arnd Bergmann wrote:

quoted

quoted

I haven't checked all architectures, but I assume what happens is that
64-bit ones just #define atomic64_t atomic_long_t, so they don't have
to provide three sets of functions.

scratch that, I just looked at all the architectures and found that it's
just completely arbitrary, even within one architecture you get a mix
of 'long' and 'long long', plus this gem from MIPS:

static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)

which truncates the result to 32 bit.

Eh...  The result is 0/1 so nothing is truncated.  Alpha, MIPS,
PARISC and PowerPC are using the same prototype and x86 only differs
in the use of inline instead __inline__.  And anyway, that function on
MIPS is only built for CONFIG_64BIT.

Ah, got it. Sorry about that.

What's wrong on MIPS is the comment describing the function's return value
which was changed by f24219b4e90cf70ec4a211b17fbabc725a0ddf3c (atomic: move
atomic_add_unless to generic code) and I've queued up a patch to fix that
since a few days.  I guess that was a cut and paste error from
__atomic_add_unless which indeed does return the old value.

Thanks!

	Arnd