[PATCH 08/11] ARC: xchg: !LLSC: remove UP micro-optimization/hack
flat view
STALE1893d
From: Vineet Gupta <hidden>
Date: 2021-08-04 19:16:31
Also in:
lkml
Subsystem:
synopsys arc architecture, the rest · Maintainers:
Vineet Gupta, Linus Torvalds
It gets in the way of cleaning things up and is a maintenance pain-in-neck ! Signed-off-by: Vineet Gupta <redacted> --- arch/arc/include/asm/cmpxchg.h | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-)
diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index d42917e803e1..bac9b564a140 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h@@ -113,15 +113,9 @@ static inline unsigned long __xchg(unsigned long val, volatile void *ptr, * - For !LLSC, cmpxchg() needs to use that lock (see above) and there is lot * of kernel code which calls xchg()/cmpxchg() on same data (see llist.h) * Hence xchg() needs to follow same locking rules. - * - * Technically the lock is also needed for UP (boils down to irq save/restore) - * but we can cheat a bit since cmpxchg() atomic_ops_lock() would cause irqs to - * be disabled thus can't possibly be interrupted/preempted/clobbered by xchg() - * Other way around, xchg is one instruction anyways, so can't be interrupted - * as such */ -#if !defined(CONFIG_ARC_HAS_LLSC) && defined(CONFIG_SMP) +#ifndef CONFIG_ARC_HAS_LLSC #define arch_xchg(ptr, with) \ ({ \
@@ -134,10 +128,6 @@ static inline unsigned long __xchg(unsigned long val, volatile void *ptr, old_val; \ }) -#else - -#define arch_xchg(ptr, with) _xchg(ptr, with) - #endif /*
--
2.25.1