locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage

Get rid of INLINE_SPIN_UNLOCK entirely replacing it with
UNINLINE_SPIN_UNLOCK instead of the reverse meaning.

Whoever wants to change the default spinlock inlining
behavior and uninline the spinlocks for some weird reason,
such as spinlock debugging, paravirt etc. can now all just
select UNINLINE_SPIN_UNLOCK

Original discussion at: https://lkml.org/lkml/2012/3/21/357

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20120322095502.30866.75756.sendpatchset@codeblue
[ tidied up the changelog a bit ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/mips/configs/db1300_defconfig

@@ -133,7 +133,7 @@ CONFIG_BLK_DEV_BSG=y
 CONFIG_IOSCHED_NOOP=y
 CONFIG_DEFAULT_NOOP=y
 CONFIG_DEFAULT_IOSCHED="noop"
-CONFIG_INLINE_SPIN_UNLOCK=y
+# CONFIG_UNINLINE_SPIN_UNLOCK is not set
 CONFIG_INLINE_SPIN_UNLOCK_IRQ=y
 CONFIG_INLINE_READ_UNLOCK=y
 CONFIG_INLINE_READ_UNLOCK_IRQ=y

arch/xtensa/configs/iss_defconfig

@@ -113,7 +113,7 @@ CONFIG_DEFAULT_IOSCHED="noop"
 # CONFIG_INLINE_SPIN_LOCK_BH is not set
 # CONFIG_INLINE_SPIN_LOCK_IRQ is not set
 # CONFIG_INLINE_SPIN_LOCK_IRQSAVE is not set
-CONFIG_INLINE_SPIN_UNLOCK=y
+# CONFIG_UNINLINE_SPIN_UNLOCK is not set
 # CONFIG_INLINE_SPIN_UNLOCK_BH is not set
 CONFIG_INLINE_SPIN_UNLOCK_IRQ=y
 # CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE is not set

include/linux/spinlock_api_smp.h

@@ -67,7 +67,7 @@ _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
 #define _raw_spin_trylock_bh(lock) __raw_spin_trylock_bh(lock)
 #endif
 
-#ifdef CONFIG_INLINE_SPIN_UNLOCK
+#ifndef CONFIG_UNINLINE_SPIN_UNLOCK
 #define _raw_spin_unlock(lock) __raw_spin_unlock(lock)
 #endif
 

kernel/Kconfig.locks

@@ -124,8 +124,8 @@ config INLINE_SPIN_LOCK_IRQSAVE
 	def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
 		 ARCH_INLINE_SPIN_LOCK_IRQSAVE
 
-config INLINE_SPIN_UNLOCK
-	def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_SPIN_UNLOCK)
+config UNINLINE_SPIN_UNLOCK
+	bool
 
 config INLINE_SPIN_UNLOCK_BH
 	def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_UNLOCK_BH

kernel/Kconfig.preempt

@@ -36,6 +36,7 @@ config PREEMPT_VOLUNTARY
 config PREEMPT
 	bool "Preemptible Kernel (Low-Latency Desktop)"
 	select PREEMPT_COUNT
+	select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
 	help
 	  This option reduces the latency of the kernel by making
 	  all kernel code (that is not executing in a critical section)

kernel/spinlock.c

@@ -163,7 +163,7 @@ void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
 EXPORT_SYMBOL(_raw_spin_lock_bh);
 #endif
 
-#ifndef CONFIG_INLINE_SPIN_UNLOCK
+#ifdef CONFIG_UNINLINE_SPIN_UNLOCK
 void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
 {
 	__raw_spin_unlock(lock);

lib/Kconfig.debug

@@ -499,6 +499,7 @@ config RT_MUTEX_TESTER
 config DEBUG_SPINLOCK
 	bool "Spinlock and rw-lock debugging: basic checks"
 	depends on DEBUG_KERNEL
+	select UNINLINE_SPIN_UNLOCK
 	help
 	  Say Y here and build SMP to catch missing spinlock initialization
 	  and certain other kinds of spinlock errors commonly made.  This is