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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-05 13:07:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-05 13:07:43 -0700
commite1d9694cae722d00a94fb58f901aa69c9c324a16 (patch)
tree19a7f36292adbc178ba4fac6f2f9e1acadb1b3f1
parent39c12be86aaedd2f81bfb2236aca5333a2334dea (diff)
parentb3a084b9b684622b149e8dcf03855bf0d5fb588b (diff)
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Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: rcu_read_lock_bh_held(): disabling irqs also disables bh generic-ipi: Fix deadlock in __smp_call_function_single
-rw-r--r--include/linux/rcupdate.h2
-rw-r--r--kernel/smp.c17
2 files changed, 15 insertions, 4 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 9fbc54a2585..83af1f8d8b7 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -454,7 +454,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* Makes rcu_dereference_check() do the dirty work.
*/
#define rcu_dereference_bh(p) \
- rcu_dereference_check(p, rcu_read_lock_bh_held())
+ rcu_dereference_check(p, rcu_read_lock_bh_held() || irqs_disabled())
/**
* rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched
diff --git a/kernel/smp.c b/kernel/smp.c
index 75c970c715d..ed6aacfcb7e 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -365,9 +365,10 @@ call:
EXPORT_SYMBOL_GPL(smp_call_function_any);
/**
- * __smp_call_function_single(): Run a function on another CPU
+ * __smp_call_function_single(): Run a function on a specific CPU
* @cpu: The CPU to run on.
* @data: Pre-allocated and setup data structure
+ * @wait: If true, wait until function has completed on specified CPU.
*
* Like smp_call_function_single(), but allow caller to pass in a
* pre-allocated data structure. Useful for embedding @data inside
@@ -376,8 +377,10 @@ EXPORT_SYMBOL_GPL(smp_call_function_any);
void __smp_call_function_single(int cpu, struct call_single_data *data,
int wait)
{
- csd_lock(data);
+ unsigned int this_cpu;
+ unsigned long flags;
+ this_cpu = get_cpu();
/*
* Can deadlock when called with interrupts disabled.
* We allow cpu's that are not yet online though, as no one else can
@@ -387,7 +390,15 @@ void __smp_call_function_single(int cpu, struct call_single_data *data,
WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled()
&& !oops_in_progress);
- generic_exec_single(cpu, data, wait);
+ if (cpu == this_cpu) {
+ local_irq_save(flags);
+ data->func(data->info);
+ local_irq_restore(flags);
+ } else {
+ csd_lock(data);
+ generic_exec_single(cpu, data, wait);
+ }
+ put_cpu();
}
/**