[PATCH 5.8 441/464] Revert "parisc: Improve interrupt handling in arch_spin_lock_flags()"

From: Greg Kroah-Hartman
Date: Mon Aug 17 2020 - 15:16:41 EST


From: Helge Deller <deller@xxxxxx>

commit 3d05b8aebc5f10ee3ab129b61100196855dd7249 upstream.

This reverts commit 2772f0efd5bbd5413db3d22e363b779ca0fa5310.
It turns out that we want to implement the spinlock code differently.

Signed-off-by: Helge Deller <deller@xxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v5.7+
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/parisc/include/asm/spinlock.h | 25 ++++++++-----------------
1 file changed, 8 insertions(+), 17 deletions(-)

--- a/arch/parisc/include/asm/spinlock.h
+++ b/arch/parisc/include/asm/spinlock.h
@@ -10,34 +10,25 @@
static inline int arch_spin_is_locked(arch_spinlock_t *x)
{
volatile unsigned int *a = __ldcw_align(x);
- smp_mb();
return *a == 0;
}

-static inline void arch_spin_lock(arch_spinlock_t *x)
-{
- volatile unsigned int *a;
-
- a = __ldcw_align(x);
- while (__ldcw(a) == 0)
- while (*a == 0)
- cpu_relax();
-}
+#define arch_spin_lock(lock) arch_spin_lock_flags(lock, 0)

static inline void arch_spin_lock_flags(arch_spinlock_t *x,
unsigned long flags)
{
volatile unsigned int *a;
- unsigned long flags_dis;

a = __ldcw_align(x);
- while (__ldcw(a) == 0) {
- local_save_flags(flags_dis);
- local_irq_restore(flags);
+ while (__ldcw(a) == 0)
while (*a == 0)
- cpu_relax();
- local_irq_restore(flags_dis);
- }
+ if (flags & PSW_SM_I) {
+ local_irq_enable();
+ cpu_relax();
+ local_irq_disable();
+ } else
+ cpu_relax();
}
#define arch_spin_lock_flags arch_spin_lock_flags