locking: Remove spin_lock_flags() etc

parisc, ia64 and powerpc32 are the only remaining architectures that
provide custom arch_{spin,read,write}_lock_flags() functions, which are
meant to re-enable interrupts while waiting for a spinlock.

However, none of these can actually run into this codepath, because
it is only called on architectures without CONFIG_GENERIC_LOCKBREAK,
or when CONFIG_DEBUG_LOCK_ALLOC is set without CONFIG_LOCKDEP, and none
of those combinations are possible on the three architectures.

Going back in the git history, it appears that arch/mn10300 may have
been able to run into this code path, but there is a good chance that
it never worked. On the architectures that still exist, it was
already impossible to hit back in 2008 after the introduction of
CONFIG_GENERIC_LOCKBREAK, and possibly earlier.

As this is all dead code, just remove it and the helper functions built
around it. For arch/ia64, the inline asm could be cleaned up, but
it seems safer to leave it untouched.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Helge Deller <deller@gmx.de>  # parisc
Link: https://lore.kernel.org/r/20211022120058.1031690-1-arnd@kernel.org

1 files changed, 0 insertions, 15 deletions

diff --git a/arch/parisc/include/asm/spinlock.h b/arch/parisc/include/asm/spinlock.h
index fa5ee8a45dbd..a6e5d66a7656 100644
--- a/arch/parisc/include/asm/spinlock.h
+++ b/arch/parisc/include/asm/spinlock.h
@@ -23,21 +23,6 @@ static inline void arch_spin_lock(arch_spinlock_t *x)
 			continue;
 }
 
-static inline void arch_spin_lock_flags(arch_spinlock_t *x,
-					unsigned long flags)
-{
-	volatile unsigned int *a;
-
-	a = __ldcw_align(x);
-	while (__ldcw(a) == 0)
-		while (*a == 0)
-			if (flags & PSW_SM_I) {
-				local_irq_enable();
-				local_irq_disable();
-			}
-}
-#define arch_spin_lock_flags arch_spin_lock_flags
-
 static inline void arch_spin_unlock(arch_spinlock_t *x)
 {
 	volatile unsigned int *a;