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-rw-r--r--arch/Kconfig3
-rw-r--r--arch/s390/Kconfig2
-rw-r--r--arch/s390/include/asm/mutex.h2
-rw-r--r--arch/s390/include/asm/processor.h2
-rw-r--r--arch/s390/include/asm/spinlock.h5
-rw-r--r--include/linux/mutex.h6
-rw-r--r--lib/lockref.c10
7 files changed, 20 insertions, 10 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index 1feb169274fe..af2cc6eabcc7 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -286,9 +286,6 @@ config HAVE_PERF_USER_STACK_DUMP
config HAVE_ARCH_JUMP_LABEL
bool
-config HAVE_ARCH_MUTEX_CPU_RELAX
- bool
-
config HAVE_RCU_TABLE_FREE
bool
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index dcc6ac2d8026..7143793859fa 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -93,6 +93,7 @@ config S390
select ARCH_INLINE_WRITE_UNLOCK_IRQ
select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
select ARCH_SAVE_PAGE_KEYS if HIBERNATION
+ select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_WANT_IPC_PARSE_VERSION
select BUILDTIME_EXTABLE_SORT
select CLONE_BACKWARDS2
@@ -102,7 +103,6 @@ config S390
select GENERIC_TIME_VSYSCALL_OLD
select HAVE_ALIGNED_STRUCT_PAGE if SLUB
select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
- select HAVE_ARCH_MUTEX_CPU_RELAX
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
diff --git a/arch/s390/include/asm/mutex.h b/arch/s390/include/asm/mutex.h
index 688271f5f2e4..458c1f7fbc18 100644
--- a/arch/s390/include/asm/mutex.h
+++ b/arch/s390/include/asm/mutex.h
@@ -7,5 +7,3 @@
*/
#include <asm-generic/mutex-dec.h>
-
-#define arch_mutex_cpu_relax() barrier()
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 0eb37505cab1..ca7821f07260 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -198,6 +198,8 @@ static inline void cpu_relax(void)
barrier();
}
+#define arch_mutex_cpu_relax() barrier()
+
static inline void psw_set_key(unsigned int key)
{
asm volatile("spka 0(%0)" : : "d" (key));
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h
index 701fe8c59e1f..83e5d216105e 100644
--- a/arch/s390/include/asm/spinlock.h
+++ b/arch/s390/include/asm/spinlock.h
@@ -44,6 +44,11 @@ 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 int arch_spin_value_unlocked(arch_spinlock_t lock)
+{
+ return lock.owner_cpu == 0;
+}
+
static inline void arch_spin_lock(arch_spinlock_t *lp)
{
int old;
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index ccd4260834c5..bab49da8a0f0 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -15,8 +15,8 @@
#include <linux/spinlock_types.h>
#include <linux/linkage.h>
#include <linux/lockdep.h>
-
#include <linux/atomic.h>
+#include <asm/processor.h>
/*
* Simple, straightforward mutexes with strict semantics:
@@ -175,8 +175,8 @@ extern void mutex_unlock(struct mutex *lock);
extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
-#ifndef CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX
-#define arch_mutex_cpu_relax() cpu_relax()
+#ifndef arch_mutex_cpu_relax
+# define arch_mutex_cpu_relax() cpu_relax()
#endif
#endif
diff --git a/lib/lockref.c b/lib/lockref.c
index e294ae445c9a..6f9d434c1521 100644
--- a/lib/lockref.c
+++ b/lib/lockref.c
@@ -12,6 +12,14 @@
#endif
/*
+ * Allow architectures to override the default cpu_relax() within CMPXCHG_LOOP.
+ * This is useful for architectures with an expensive cpu_relax().
+ */
+#ifndef arch_mutex_cpu_relax
+# define arch_mutex_cpu_relax() cpu_relax()
+#endif
+
+/*
* Note that the "cmpxchg()" reloads the "old" value for the
* failure case.
*/
@@ -28,7 +36,7 @@
if (likely(old.lock_count == prev.lock_count)) { \
SUCCESS; \
} \
- cpu_relax(); \
+ arch_mutex_cpu_relax(); \
} \
} while (0)