locking/mcs: Allow architecture specific asm files to be used for contended case

This patch allows each architecture to add its specific assembly optimized
arch_mcs_spin_lock_contended and arch_mcs_spinlock_uncontended for
MCS lock and unlock functions.

Signed-off-by: Tim Chen <[e-mail]>
Cc: Scott J Norton <[e-mail]>
Cc: Raghavendra K T <[e-mail]>
Cc: AswinChandramouleeswaran <[e-mail]>
Cc: George Spelvin <[e-mail]>
Cc: Rik vanRiel <[e-mail]>
Cc: Andrea Arcangeli <[e-mail]>
Cc: MichelLespinasse <[e-mail]>
Cc: Peter Hurley <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Alex Shi <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Tim Chen <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: "Figo.zhang" <[e-mail]>
Cc: "Paul E.McKenney" <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Davidlohr Bueso <[e-mail]>
Cc: Waiman Long <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Matthew R Wilcox <[e-mail]>
Signed-off-by: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/1390347382.3138.67.camel@schen9-DESK
Signed-off-by: Ingo Molnar <[e-mail]>

arch/alpha/include/asm/Kbuild

···
 generic-y += clkdev.h
 generic-y += exec.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += trace_clock.h

arch/arc/include/asm/Kbuild

···
 generic-y += kvm_para.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += msgbuf.h
 generic-y += param.h

arch/arm/include/asm/Kbuild

···
 generic-y += kdebug.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += msgbuf.h
 generic-y += param.h
 generic-y += parport.h

arch/arm64/include/asm/Kbuild

···
 generic-y += kvm_para.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += msgbuf.h
 generic-y += mutex.h

arch/avr32/include/asm/Kbuild

···
 generic-y += irq_regs.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += param.h
 generic-y += percpu.h
 generic-y += preempt.h

arch/blackfin/include/asm/Kbuild

···
 generic-y += kvm_para.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += msgbuf.h
 generic-y += mutex.h

arch/c6x/include/asm/Kbuild

···
 generic-y += kdebug.h
 generic-y += kmap_types.h
 generic-y += local.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += mmu.h
 generic-y += mmu_context.h

arch/cris/include/asm/Kbuild

···
 generic-y += hash.h
 generic-y += kvm_para.h
 generic-y += linkage.h
+generic-y += mcs_spinlock.h
 generic-y += module.h
 generic-y += preempt.h
 generic-y += trace_clock.h

arch/frv/include/asm/Kbuild

···
 generic-y += clkdev.h
 generic-y += exec.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += trace_clock.h

arch/hexagon/include/asm/Kbuild

···
 generic-y += kmap_types.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += msgbuf.h
 generic-y += pci.h

arch/ia64/include/asm/Kbuild

···
 generic-y += exec.h
 generic-y += hash.h
 generic-y += kvm_para.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += trace_clock.h
 generic-y += vtime.h

arch/m32r/include/asm/Kbuild

···
 generic-y += clkdev.h
 generic-y += exec.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += module.h
 generic-y += preempt.h
 generic-y += trace_clock.h

arch/m68k/include/asm/Kbuild

···
 generic-y += kvm_para.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += mutex.h
 generic-y += percpu.h

arch/metag/include/asm/Kbuild

···
 generic-y += kvm_para.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += msgbuf.h
 generic-y += mutex.h
 generic-y += param.h

arch/microblaze/include/asm/Kbuild

···
 generic-y += clkdev.h
 generic-y += exec.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += syscalls.h
 generic-y += trace_clock.h

arch/mips/include/asm/Kbuild

···
 generic-y += emergency-restart.h
 generic-y += hash.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mutex.h
 generic-y += parport.h
 generic-y += percpu.h

arch/mn10300/include/asm/Kbuild

···
 generic-y += clkdev.h
 generic-y += exec.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += trace_clock.h

arch/openrisc/include/asm/Kbuild

···
 generic-y += kmap_types.h
 generic-y += kvm_para.h
 generic-y += local.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += module.h
 generic-y += msgbuf.h

arch/parisc/include/asm/Kbuild

···
 generic-y += kvm_para.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mutex.h
 generic-y += param.h
 generic-y += percpu.h

arch/powerpc/include/asm/Kbuild

···
 
 generic-y += clkdev.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += rwsem.h
 generic-y += trace_clock.h

arch/s390/include/asm/Kbuild

···
 
 generic-y += clkdev.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += trace_clock.h

arch/score/include/asm/Kbuild

···
 generic-y += barrier.h
 generic-y += clkdev.h
 generic-y += hash.h
+generic-y += mcs_spinlock.h
 generic-y += preempt.h
 generic-y += trace_clock.h
 generic-y += xor.h

arch/sh/include/asm/Kbuild

···
 generic-y += kvm_para.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += msgbuf.h
 generic-y += param.h

arch/sparc/include/asm/Kbuild

···
 generic-y += linkage.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += module.h
 generic-y += mutex.h
 generic-y += preempt.h

arch/tile/include/asm/Kbuild

···
 generic-y += irq_regs.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += msgbuf.h
 generic-y += mutex.h
 generic-y += param.h

arch/um/include/asm/Kbuild

···
 generic-y += io.h
 generic-y += irq_regs.h
 generic-y += kdebug.h
+generic-y += mcs_spinlock.h
 generic-y += mutex.h
 generic-y += param.h
 generic-y += pci.h

arch/unicore32/include/asm/Kbuild

···
 generic-y += kdebug.h
 generic-y += kmap_types.h
 generic-y += local.h
+generic-y += mcs_spinlock.h
 generic-y += mman.h
 generic-y += module.h
 generic-y += msgbuf.h

arch/x86/include/asm/Kbuild

···
 genhdr-y += unistd_x32.h
 
 generic-y += clkdev.h
+generic-y += mcs_spinlock.h

arch/xtensa/include/asm/Kbuild

···
 generic-y += linkage.h
 generic-y += local.h
 generic-y += local64.h
+generic-y += mcs_spinlock.h
 generic-y += percpu.h
 generic-y += preempt.h
 generic-y += resource.h

include/asm-generic/mcs_spinlock.h

···
+#ifndef __ASM_MCS_SPINLOCK_H
+#define __ASM_MCS_SPINLOCK_H
+
+/*
+ * Architectures can define their own:
+ *
+ *   arch_mcs_spin_lock_contended(l)
+ *   arch_mcs_spin_unlock_contended(l)
+ *
+ * See kernel/locking/mcs_spinlock.c.
+ */
+
+#endif /* __ASM_MCS_SPINLOCK_H */

include/linux/mcs_spinlock.h

···
 #ifndef __LINUX_MCS_SPINLOCK_H
 #define __LINUX_MCS_SPINLOCK_H
 
+#include <asm/mcs_spinlock.h>
+
 struct mcs_spinlock {
 	struct mcs_spinlock *next;
 	int locked; /* 1 if lock acquired */