locking: Allow arch-inlined spinlocks

This allows an architecture to specify per lock variant if the
locking code should be kept out-of-line or inlined.

If an architecure wants out-of-line locking code no change is
needed. To force inlining of e.g. spin_lock() the line:

  #define __always_inline__spin_lock

needs to be added to arch/<...>/include/asm/spinlock.h

If CONFIG_DEBUG_SPINLOCK or CONFIG_GENERIC_LOCKBREAK are
defined the per architecture defines are (partly) ignored and
still out-of-line spinlock code will be generated.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Horst Hartmann <horsth@linux.vnet.ibm.com>
Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <20090831124418.375299024@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 175 insertions, 0 deletions

diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h
index 6b108f5fb149..1a411e3fab95 100644
--- a/include/linux/spinlock_api_smp.h
+++ b/include/linux/spinlock_api_smp.h
@@ -60,6 +60,125 @@ void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
                                                         __releases(lock);
 
+#ifndef CONFIG_DEBUG_SPINLOCK
+#ifndef CONFIG_GENERIC_LOCKBREAK
+
+#ifdef __always_inline__spin_lock
+#define _spin_lock(lock) __spin_lock(lock)
+#endif
+
+#ifdef __always_inline__read_lock
+#define _read_lock(lock) __read_lock(lock)
+#endif
+
+#ifdef __always_inline__write_lock
+#define _write_lock(lock) __write_lock(lock)
+#endif
+
+#ifdef __always_inline__spin_lock_bh
+#define _spin_lock_bh(lock) __spin_lock_bh(lock)
+#endif
+
+#ifdef __always_inline__read_lock_bh
+#define _read_lock_bh(lock) __read_lock_bh(lock)
+#endif
+
+#ifdef __always_inline__write_lock_bh
+#define _write_lock_bh(lock) __write_lock_bh(lock)
+#endif
+
+#ifdef __always_inline__spin_lock_irq
+#define _spin_lock_irq(lock) __spin_lock_irq(lock)
+#endif
+
+#ifdef __always_inline__read_lock_irq
+#define _read_lock_irq(lock) __read_lock_irq(lock)
+#endif
+
+#ifdef __always_inline__write_lock_irq
+#define _write_lock_irq(lock) __write_lock_irq(lock)
+#endif
+
+#ifdef __always_inline__spin_lock_irqsave
+#define _spin_lock_irqsave(lock) __spin_lock_irqsave(lock)
+#endif
+
+#ifdef __always_inline__read_lock_irqsave
+#define _read_lock_irqsave(lock) __read_lock_irqsave(lock)
+#endif
+
+#ifdef __always_inline__write_lock_irqsave
+#define _write_lock_irqsave(lock) __write_lock_irqsave(lock)
+#endif
+
+#endif /* !CONFIG_GENERIC_LOCKBREAK */
+
+#ifdef __always_inline__spin_trylock
+#define _spin_trylock(lock) __spin_trylock(lock)
+#endif
+
+#ifdef __always_inline__read_trylock
+#define _read_trylock(lock) __read_trylock(lock)
+#endif
+
+#ifdef __always_inline__write_trylock
+#define _write_trylock(lock) __write_trylock(lock)
+#endif
+
+#ifdef __always_inline__spin_trylock_bh
+#define _spin_trylock_bh(lock) __spin_trylock_bh(lock)
+#endif
+
+#ifdef __always_inline__spin_unlock
+#define _spin_unlock(lock) __spin_unlock(lock)
+#endif
+
+#ifdef __always_inline__read_unlock
+#define _read_unlock(lock) __read_unlock(lock)
+#endif
+
+#ifdef __always_inline__write_unlock
+#define _write_unlock(lock) __write_unlock(lock)
+#endif
+
+#ifdef __always_inline__spin_unlock_bh
+#define _spin_unlock_bh(lock) __spin_unlock_bh(lock)
+#endif
+
+#ifdef __always_inline__read_unlock_bh
+#define _read_unlock_bh(lock) __read_unlock_bh(lock)
+#endif
+
+#ifdef __always_inline__write_unlock_bh
+#define _write_unlock_bh(lock) __write_unlock_bh(lock)
+#endif
+
+#ifdef __always_inline__spin_unlock_irq
+#define _spin_unlock_irq(lock) __spin_unlock_irq(lock)
+#endif
+
+#ifdef __always_inline__read_unlock_irq
+#define _read_unlock_irq(lock) __read_unlock_irq(lock)
+#endif
+
+#ifdef __always_inline__write_unlock_irq
+#define _write_unlock_irq(lock) __write_unlock_irq(lock)
+#endif
+
+#ifdef __always_inline__spin_unlock_irqrestore
+#define _spin_unlock_irqrestore(lock, flags) __spin_unlock_irqrestore(lock, flags)
+#endif
+
+#ifdef __always_inline__read_unlock_irqrestore
+#define _read_unlock_irqrestore(lock, flags) __read_unlock_irqrestore(lock, flags)
+#endif
+
+#ifdef __always_inline__write_unlock_irqrestore
+#define _write_unlock_irqrestore(lock, flags) __write_unlock_irqrestore(lock, flags)
+#endif
+
+#endif /* CONFIG_DEBUG_SPINLOCK */
+
 static inline int __spin_trylock(spinlock_t *lock)
 {
         preempt_disable();
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index 2c000f5c070b..5ddab730cb2f 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -21,23 +21,29 @@
 #include <linux/debug_locks.h>
 #include <linux/module.h>
 
+#ifndef _spin_trylock
 int __lockfunc _spin_trylock(spinlock_t *lock)
 {
         return __spin_trylock(lock);
 }
 EXPORT_SYMBOL(_spin_trylock);
+#endif
 
+#ifndef _read_trylock
 int __lockfunc _read_trylock(rwlock_t *lock)
 {
         return __read_trylock(lock);
 }
 EXPORT_SYMBOL(_read_trylock);
+#endif
 
+#ifndef _write_trylock
 int __lockfunc _write_trylock(rwlock_t *lock)
 {
         return __write_trylock(lock);
 }
 EXPORT_SYMBOL(_write_trylock);
+#endif
 
 /*
  * If lockdep is enabled then we use the non-preemption spin-ops
@@ -46,77 +52,101 @@ EXPORT_SYMBOL(_write_trylock);
  */
 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
 
+#ifndef _read_lock
 void __lockfunc _read_lock(rwlock_t *lock)
 {
         __read_lock(lock);
 }
 EXPORT_SYMBOL(_read_lock);
+#endif
 
+#ifndef _spin_lock_irqsave
 unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
 {
         return __spin_lock_irqsave(lock);
 }
 EXPORT_SYMBOL(_spin_lock_irqsave);
+#endif
 
+#ifndef _spin_lock_irq
 void __lockfunc _spin_lock_irq(spinlock_t *lock)
 {
         __spin_lock_irq(lock);
 }
 EXPORT_SYMBOL(_spin_lock_irq);
+#endif
 
+#ifndef _spin_lock_bh
 void __lockfunc _spin_lock_bh(spinlock_t *lock)
 {
         __spin_lock_bh(lock);
 }
 EXPORT_SYMBOL(_spin_lock_bh);
+#endif
 
+#ifndef _read_lock_irqsave
 unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
 {
         return __read_lock_irqsave(lock);
 }
 EXPORT_SYMBOL(_read_lock_irqsave);
+#endif
 
+#ifndef _read_lock_irq
 void __lockfunc _read_lock_irq(rwlock_t *lock)
 {
         __read_lock_irq(lock);
 }
 EXPORT_SYMBOL(_read_lock_irq);
+#endif
 
+#ifndef _read_lock_bh
 void __lockfunc _read_lock_bh(rwlock_t *lock)
 {
         __read_lock_bh(lock);
 }
 EXPORT_SYMBOL(_read_lock_bh);
+#endif
 
+#ifndef _write_lock_irqsave
 unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
 {
         return __write_lock_irqsave(lock);
 }
 EXPORT_SYMBOL(_write_lock_irqsave);
+#endif
 
+#ifndef _write_lock_irq
 void __lockfunc _write_lock_irq(rwlock_t *lock)
 {
         __write_lock_irq(lock);
 }
 EXPORT_SYMBOL(_write_lock_irq);
+#endif
 
+#ifndef _write_lock_bh
 void __lockfunc _write_lock_bh(rwlock_t *lock)
 {
         __write_lock_bh(lock);
 }
 EXPORT_SYMBOL(_write_lock_bh);
+#endif
 
+#ifndef _spin_lock
 void __lockfunc _spin_lock(spinlock_t *lock)
 {
         __spin_lock(lock);
 }
 EXPORT_SYMBOL(_spin_lock);
+#endif
 
+#ifndef _write_lock
 void __lockfunc _write_lock(rwlock_t *lock)
 {
         __write_lock(lock);
 }
 EXPORT_SYMBOL(_write_lock);
+#endif
 
 #else /* CONFIG_PREEMPT: */
 
@@ -242,83 +272,109 @@ EXPORT_SYMBOL(_spin_lock_nest_lock);
 
 #endif
 
+#ifndef _spin_unlock
 void __lockfunc _spin_unlock(spinlock_t *lock)
 {
         __spin_unlock(lock);
 }
 EXPORT_SYMBOL(_spin_unlock);
+#endif
 
+#ifndef _write_unlock
 void __lockfunc _write_unlock(rwlock_t *lock)
 {
         __write_unlock(lock);
 }
 EXPORT_SYMBOL(_write_unlock);
+#endif
 
+#ifndef _read_unlock
 void __lockfunc _read_unlock(rwlock_t *lock)
 {
         __read_unlock(lock);
 }
 EXPORT_SYMBOL(_read_unlock);
+#endif
 
+#ifndef _spin_unlock_irqrestore
 void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 {
         __spin_unlock_irqrestore(lock, flags);
 }
 EXPORT_SYMBOL(_spin_unlock_irqrestore);
+#endif
 
+#ifndef _spin_unlock_irq
 void __lockfunc _spin_unlock_irq(spinlock_t *lock)
 {
         __spin_unlock_irq(lock);
 }
 EXPORT_SYMBOL(_spin_unlock_irq);
+#endif
 
+#ifndef _spin_unlock_bh
 void __lockfunc _spin_unlock_bh(spinlock_t *lock)
 {
         __spin_unlock_bh(lock);
 }
 EXPORT_SYMBOL(_spin_unlock_bh);
+#endif
 
+#ifndef _read_unlock_irqrestore
 void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 {
         __read_unlock_irqrestore(lock, flags);
 }
 EXPORT_SYMBOL(_read_unlock_irqrestore);
+#endif
 
+#ifndef _read_unlock_irq
 void __lockfunc _read_unlock_irq(rwlock_t *lock)
 {
         __read_unlock_irq(lock);
 }
 EXPORT_SYMBOL(_read_unlock_irq);
+#endif
 
+#ifndef _read_unlock_bh
 void __lockfunc _read_unlock_bh(rwlock_t *lock)
 {
         __read_unlock_bh(lock);
 }
 EXPORT_SYMBOL(_read_unlock_bh);
+#endif
 
+#ifndef _write_unlock_irqrestore
 void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 {
         __write_unlock_irqrestore(lock, flags);
 }
 EXPORT_SYMBOL(_write_unlock_irqrestore);
+#endif
 
+#ifndef _write_unlock_irq
 void __lockfunc _write_unlock_irq(rwlock_t *lock)
 {
         __write_unlock_irq(lock);
 }
 EXPORT_SYMBOL(_write_unlock_irq);
+#endif
 
+#ifndef _write_unlock_bh
 void __lockfunc _write_unlock_bh(rwlock_t *lock)
 {
         __write_unlock_bh(lock);
 }
 EXPORT_SYMBOL(_write_unlock_bh);
+#endif
 
+#ifndef _spin_trylock_bh
 int __lockfunc _spin_trylock_bh(spinlock_t *lock)
 {
         return __spin_trylock_bh(lock);
 }
 EXPORT_SYMBOL(_spin_trylock_bh);
+#endif
 
 notrace int in_lock_functions(unsigned long addr)
 {