Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 75 insertions, 54 deletions

diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 83e5d216105e..96879f7ad6da 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -11,18 +11,21 @@
 
 #include <linux/smp.h>
 
+#define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval)
+
 extern int spin_retry;
 
 static inline int
-_raw_compare_and_swap(volatile unsigned int *lock,
-		      unsigned int old, unsigned int new)
+_raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new)
 {
+	unsigned int old_expected = old;
+
 	asm volatile(
 		"	cs	%0,%3,%1"
 		: "=d" (old), "=Q" (*lock)
 		: "0" (old), "d" (new), "Q" (*lock)
 		: "cc", "memory" );
-	return old;
+	return old == old_expected;
 }
 
 /*
@@ -34,57 +37,69 @@ _raw_compare_and_swap(volatile unsigned int *lock,
  * (the type definitions are in asm/spinlock_types.h)
  */
 
-#define arch_spin_is_locked(x) ((x)->owner_cpu != 0)
-#define arch_spin_unlock_wait(lock) \
-	do { while (arch_spin_is_locked(lock)) \
-		 arch_spin_relax(lock); } while (0)
+void arch_spin_lock_wait(arch_spinlock_t *);
+int arch_spin_trylock_retry(arch_spinlock_t *);
+void arch_spin_relax(arch_spinlock_t *);
+void arch_spin_lock_wait_flags(arch_spinlock_t *, unsigned long flags);
 
-extern void arch_spin_lock_wait(arch_spinlock_t *);
-extern void arch_spin_lock_wait_flags(arch_spinlock_t *, unsigned long flags);
-extern int arch_spin_trylock_retry(arch_spinlock_t *);
-extern void arch_spin_relax(arch_spinlock_t *lock);
+static inline u32 arch_spin_lockval(int cpu)
+{
+	return ~cpu;
+}
 
 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
 {
-	return lock.owner_cpu == 0;
+	return lock.lock == 0;
 }
 
-static inline void arch_spin_lock(arch_spinlock_t *lp)
+static inline int arch_spin_is_locked(arch_spinlock_t *lp)
 {
-	int old;
+	return ACCESS_ONCE(lp->lock) != 0;
+}
 
-	old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
-	if (likely(old == 0))
-		return;
-	arch_spin_lock_wait(lp);
+static inline int arch_spin_trylock_once(arch_spinlock_t *lp)
+{
+	barrier();
+	return likely(arch_spin_value_unlocked(*lp) &&
+		      _raw_compare_and_swap(&lp->lock, 0, SPINLOCK_LOCKVAL));
 }
 
-static inline void arch_spin_lock_flags(arch_spinlock_t *lp,
-					 unsigned long flags)
+static inline int arch_spin_tryrelease_once(arch_spinlock_t *lp)
 {
-	int old;
+	return _raw_compare_and_swap(&lp->lock, SPINLOCK_LOCKVAL, 0);
+}
 
-	old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
-	if (likely(old == 0))
-		return;
-	arch_spin_lock_wait_flags(lp, flags);
+static inline void arch_spin_lock(arch_spinlock_t *lp)
+{
+	if (!arch_spin_trylock_once(lp))
+		arch_spin_lock_wait(lp);
 }
 
-static inline int arch_spin_trylock(arch_spinlock_t *lp)
+static inline void arch_spin_lock_flags(arch_spinlock_t *lp,
+					unsigned long flags)
 {
-	int old;
+	if (!arch_spin_trylock_once(lp))
+		arch_spin_lock_wait_flags(lp, flags);
+}
 
-	old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
-	if (likely(old == 0))
-		return 1;
-	return arch_spin_trylock_retry(lp);
+static inline int arch_spin_trylock(arch_spinlock_t *lp)
+{
+	if (!arch_spin_trylock_once(lp))
+		return arch_spin_trylock_retry(lp);
+	return 1;
 }
 
 static inline void arch_spin_unlock(arch_spinlock_t *lp)
 {
-	_raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0);
+	arch_spin_tryrelease_once(lp);
+}
+
+static inline void arch_spin_unlock_wait(arch_spinlock_t *lock)
+{
+	while (arch_spin_is_locked(lock))
+		arch_spin_relax(lock);
 }
-		
+
 /*
  * Read-write spinlocks, allowing multiple readers
  * but only one writer.
@@ -115,42 +130,50 @@ extern void _raw_write_lock_wait(arch_rwlock_t *lp);
 extern void _raw_write_lock_wait_flags(arch_rwlock_t *lp, unsigned long flags);
 extern int _raw_write_trylock_retry(arch_rwlock_t *lp);
 
+static inline int arch_read_trylock_once(arch_rwlock_t *rw)
+{
+	unsigned int old = ACCESS_ONCE(rw->lock);
+	return likely((int) old >= 0 &&
+		      _raw_compare_and_swap(&rw->lock, old, old + 1));
+}
+
+static inline int arch_write_trylock_once(arch_rwlock_t *rw)
+{
+	unsigned int old = ACCESS_ONCE(rw->lock);
+	return likely(old == 0 &&
+		      _raw_compare_and_swap(&rw->lock, 0, 0x80000000));
+}
+
 static inline void arch_read_lock(arch_rwlock_t *rw)
 {
-	unsigned int old;
-	old = rw->lock & 0x7fffffffU;
-	if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old)
+	if (!arch_read_trylock_once(rw))
 		_raw_read_lock_wait(rw);
 }
 
 static inline void arch_read_lock_flags(arch_rwlock_t *rw, unsigned long flags)
 {
-	unsigned int old;
-	old = rw->lock & 0x7fffffffU;
-	if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old)
+	if (!arch_read_trylock_once(rw))
 		_raw_read_lock_wait_flags(rw, flags);
 }
 
 static inline void arch_read_unlock(arch_rwlock_t *rw)
 {
-	unsigned int old, cmp;
+	unsigned int old;
 
-	old = rw->lock;
 	do {
-		cmp = old;
-		old = _raw_compare_and_swap(&rw->lock, old, old - 1);
-	} while (cmp != old);
+		old = ACCESS_ONCE(rw->lock);
+	} while (!_raw_compare_and_swap(&rw->lock, old, old - 1));
 }
 
 static inline void arch_write_lock(arch_rwlock_t *rw)
 {
-	if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
+	if (!arch_write_trylock_once(rw))
 		_raw_write_lock_wait(rw);
 }
 
 static inline void arch_write_lock_flags(arch_rwlock_t *rw, unsigned long flags)
 {
-	if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
+	if (!arch_write_trylock_once(rw))
 		_raw_write_lock_wait_flags(rw, flags);
 }
 
@@ -161,18 +184,16 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
 
 static inline int arch_read_trylock(arch_rwlock_t *rw)
 {
-	unsigned int old;
-	old = rw->lock & 0x7fffffffU;
-	if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1) == old))
-		return 1;
-	return _raw_read_trylock_retry(rw);
+	if (!arch_read_trylock_once(rw))
+		return _raw_read_trylock_retry(rw);
+	return 1;
 }
 
 static inline int arch_write_trylock(arch_rwlock_t *rw)
 {
-	if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))
-		return 1;
-	return _raw_write_trylock_retry(rw);
+	if (!arch_write_trylock_once(rw))
+		return _raw_write_trylock_retry(rw);
+	return 1;
 }
 
 #define arch_read_relax(lock)	cpu_relax()