s390 needs a special version of cpu_relax() for the new lockref code. The new variant should be a no-op but also have memory barrier semantics, since that is what the default cpu_relax() variant implements.
Actually s390 had the same problem already in the past where we implemented arch_mutex_cpu_relax() for nearly the same reason within the common mutex code. So before we end up adding a special arch_lockref_cpu_relax() variant which would only differ in the name from arch_mutex_cpu_relax(), rename the current arch_mutex_cpu_relax() variant to a more general cpu_relax_simple(), which can be used also in the lockref code. Signed-off-by: Heiko Carstens <[email protected]> --- arch/Kconfig | 2 +- arch/s390/Kconfig | 2 +- arch/s390/include/asm/mutex.h | 2 -- arch/s390/include/asm/processor.h | 2 ++ include/linux/mutex.h | 4 ---- include/linux/spinlock_up.h | 4 ++++ kernel/mutex.c | 8 ++++---- 7 files changed, 12 insertions(+), 12 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 1feb169..74069bd 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -286,7 +286,7 @@ config HAVE_PERF_USER_STACK_DUMP config HAVE_ARCH_JUMP_LABEL bool -config HAVE_ARCH_MUTEX_CPU_RELAX +config HAVE_CPU_RELAX_SIMPLE bool config HAVE_RCU_TABLE_FREE diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index dcc6ac2..9789282 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -102,13 +102,13 @@ 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 select HAVE_BPF_JIT if 64BIT && PACK_STACK select HAVE_CMPXCHG_DOUBLE select HAVE_CMPXCHG_LOCAL + select HAVE_CPU_RELAX_SIMPLE select HAVE_C_RECORDMCOUNT select HAVE_DEBUG_KMEMLEAK select HAVE_DYNAMIC_FTRACE diff --git a/arch/s390/include/asm/mutex.h b/arch/s390/include/asm/mutex.h index 688271f..458c1f7 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 0eb3750..338a488 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 cpu_relax_simple() barrier() + static inline void psw_set_key(unsigned int key) { asm volatile("spka 0(%0)" : : "d" (key)); diff --git a/include/linux/mutex.h b/include/linux/mutex.h index ccd4260..084f799 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -175,8 +175,4 @@ 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() -#endif - #endif diff --git a/include/linux/spinlock_up.h b/include/linux/spinlock_up.h index 8b3ac0d..7e1cc42 100644 --- a/include/linux/spinlock_up.h +++ b/include/linux/spinlock_up.h @@ -7,6 +7,10 @@ #include <asm/processor.h> /* for cpu_relax() */ +#ifndef CONFIG_HAVE_CPU_RELAX_SIMPLE +#define cpu_relax_simple() cpu_relax() +#endif + /* * include/linux/spinlock_up.h - UP-debug version of spinlocks. * diff --git a/kernel/mutex.c b/kernel/mutex.c index 6d647ae..e0ce0da2 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -139,7 +139,7 @@ void mspin_lock(struct mspin_node **lock, struct mspin_node *node) smp_wmb(); /* Wait until the lock holder passes the lock down */ while (!ACCESS_ONCE(node->locked)) - arch_mutex_cpu_relax(); + cpu_relax_simple(); } static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node) @@ -154,7 +154,7 @@ static void mspin_unlock(struct mspin_node **lock, struct mspin_node *node) return; /* Wait until the next pointer is set */ while (!(next = ACCESS_ONCE(node->next))) - arch_mutex_cpu_relax(); + cpu_relax_simple(); } ACCESS_ONCE(next->locked) = 1; smp_wmb(); @@ -192,7 +192,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) if (need_resched()) break; - arch_mutex_cpu_relax(); + cpu_relax_simple(); } rcu_read_unlock(); @@ -509,7 +509,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, * memory barriers as we'll eventually observe the right * values at the cost of a few extra spins. */ - arch_mutex_cpu_relax(); + cpu_relax_simple(); } slowpath: #endif -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
