We introduce a configuration variable for the feature to make it easier for
various architectures and/or configs to enable or disable it based on their
requirements.
Signed-off-by: Gregory Haskins <ghaskins@xxxxxxxxxx>
---
kernel/Kconfig.preempt | 9 +++++++++
kernel/spinlock.c | 7 +++----
lib/Kconfig.debug | 1 +
3 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 41a0d88..5b45213 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -86,6 +86,15 @@ config PREEMPT
default y
depends on PREEMPT_DESKTOP || PREEMPT_RT
+config DISABLE_PREEMPT_SPINLOCK_WAITERS
+ bool
+ default n
+
+config PREEMPT_SPINLOCK_WAITERS
+ bool
+ default y
+ depends on PREEMPT && SMP && !DISABLE_PREEMPT_SPINLOCK_WAITERS
+
config PREEMPT_SOFTIRQS
bool "Thread Softirqs"
default n
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index b0e7f02..2e6a904 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -116,8 +116,7 @@ EXPORT_SYMBOL(__write_trylock_irqsave);
* even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
* not re-enabled during lock-acquire (which the preempt-spin-ops do):
*/
-#if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP) || \
- defined(CONFIG_DEBUG_LOCK_ALLOC)
+#if !defined(CONFIG_PREEMPT_SPINLOCK_WAITERS)
void __lockfunc __read_lock(raw_rwlock_t *lock)
{
@@ -244,7 +243,7 @@ void __lockfunc __write_lock(raw_rwlock_t *lock)
EXPORT_SYMBOL(__write_lock);
-#else /* CONFIG_PREEMPT: */
+#else /* CONFIG_PREEMPT_SPINLOCK_WAITERS */
/*
* This could be a long-held lock. We both prepare to spin for a long
@@ -334,7 +333,7 @@ BUILD_LOCK_OPS(spin, raw_spinlock);
BUILD_LOCK_OPS(read, raw_rwlock);
BUILD_LOCK_OPS(write, raw_rwlock);
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPT_SPINLOCK_WAITERS */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9208791..f2889b2 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -233,6 +233,7 @@ config DEBUG_LOCK_ALLOC
bool "Lock debugging: detect incorrect freeing of live locks"
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
select DEBUG_SPINLOCK
+ select DISABLE_PREEMPT_SPINLOCK_WAITERS
select DEBUG_MUTEXES
select LOCKDEP
help
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