* Andrea Parri <andrea.pa...@amarulasolutions.com> wrote:
> Hi Ingo,
>
> > From 5affbf7e91901143f84f1b2ca64f4afe70e210fd Mon Sep 17 00:00:00 2001
> > From: Ingo Molnar <mi...@kernel.org>
> > Date: Sat, 5 May 2018 10:23:23 +0200
> > Subject: [PATCH] locking/atomics: Simplify the op definitions in atomic.h
> > some more
> >
> > Before:
> >
> > #ifndef atomic_fetch_dec_relaxed
> > # ifndef atomic_fetch_dec
> > # define atomic_fetch_dec(v) atomic_fetch_sub(1, (v))
> > # define atomic_fetch_dec_relaxed(v)
> > atomic_fetch_sub_relaxed(1, (v))
> > # define atomic_fetch_dec_acquire(v)
> > atomic_fetch_sub_acquire(1, (v))
> > # define atomic_fetch_dec_release(v)
> > atomic_fetch_sub_release(1, (v))
> > # else
> > # define atomic_fetch_dec_relaxed atomic_fetch_dec
> > # define atomic_fetch_dec_acquire atomic_fetch_dec
> > # define atomic_fetch_dec_release atomic_fetch_dec
> > # endif
> > #else
> > # ifndef atomic_fetch_dec_acquire
> > # define atomic_fetch_dec_acquire(...)
> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> > # endif
> > # ifndef atomic_fetch_dec_release
> > # define atomic_fetch_dec_release(...)
> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> > # endif
> > # ifndef atomic_fetch_dec
> > # define atomic_fetch_dec(...)
> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> > # endif
> > #endif
> >
> > After:
> >
> > #ifndef atomic_fetch_dec_relaxed
> > # ifndef atomic_fetch_dec
> > # define atomic_fetch_dec(v) atomic_fetch_sub(1, (v))
> > # define atomic_fetch_dec_relaxed(v)
> > atomic_fetch_sub_relaxed(1, (v))
> > # define atomic_fetch_dec_acquire(v)
> > atomic_fetch_sub_acquire(1, (v))
> > # define atomic_fetch_dec_release(v)
> > atomic_fetch_sub_release(1, (v))
> > # else
> > # define atomic_fetch_dec_relaxed atomic_fetch_dec
> > # define atomic_fetch_dec_acquire atomic_fetch_dec
> > # define atomic_fetch_dec_release atomic_fetch_dec
> > # endif
> > #else
> > # ifndef atomic_fetch_dec
> > # define atomic_fetch_dec(...)
> > __atomic_op_fence(atomic_fetch_dec, __VA_ARGS__)
> > # define atomic_fetch_dec_acquire(...)
> > __atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
> > # define atomic_fetch_dec_release(...)
> > __atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
> > # endif
> > #endif
> >
> > The idea is that because we already group these APIs by certain defines
> > such as atomic_fetch_dec_relaxed and atomic_fetch_dec in the primary
> > branches - we can do the same in the secondary branch as well.
> >
> > ( Also remove some unnecessarily duplicate comments, as the API
> > group defines are now pretty much self-documenting. )
> >
> > No change in functionality.
> >
> > Cc: Peter Zijlstra <pet...@infradead.org>
> > Cc: Linus Torvalds <torva...@linux-foundation.org>
> > Cc: Andrew Morton <a...@linux-foundation.org>
> > Cc: Thomas Gleixner <t...@linutronix.de>
> > Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> > Cc: Will Deacon <will.dea...@arm.com>
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Ingo Molnar <mi...@kernel.org>
>
> This breaks compilation on RISC-V. (For some of its atomics, the arch
> currently defines the _relaxed and the full variants and it relies on
> the generic definitions for the _acquire and the _release variants.)
I don't have cross-compilation for RISC-V, which is a relatively new arch.
(Is there any RISC-V set of cross-compilation tools on kernel.org somewhere?)
Could you please send a patch that defines those variants against Linus's tree,
like the PowerPC patch that does something similar:
0476a632cb3a: locking/atomics/powerpc: Move cmpxchg helpers to asm/cmpxchg.h
and define the full set of cmpxchg APIs
?
... and I'll integrate it into the proper place to make it all bisectable, etc.
Thanks,
Ingo
