1 files changed, 16 insertions, 41 deletions

diff --git a/arch/x86/kernel/smp_64.c b/arch/x86/kernel/smp_64.c
index aa2edb7f3a51..e4494e829dfa 100644
--- a/arch/x86/kernel/smp_64.c
+++ b/arch/x86/kernel/smp_64.c
@@ -354,26 +354,30 @@ static void __smp_call_function(void (*func) (void *info), void *info,
 }
 
 
-/*
- * this function sends a 'generic call function' IPI to all other CPU
- * of the system defined in the mask.
- */
-static int __smp_call_function_mask(cpumask_t mask,
-                                    void (*func)(void *), void *info,
-                                    int wait)
+int native_smp_call_function_mask(cpumask_t mask,
+                                  void (*func)(void *), void *info,
+                                  int wait)
 {
         struct call_data_struct data;
         cpumask_t allbutself;
         int cpus;
 
+        /* Can deadlock when called with interrupts disabled */
+        WARN_ON(irqs_disabled());
+
+        /* Holding any lock stops cpus from going down. */
+        spin_lock(&call_lock);
+
         allbutself = cpu_online_map;
         cpu_clear(smp_processor_id(), allbutself);
 
         cpus_and(mask, mask, allbutself);
         cpus = cpus_weight(mask);
 
-        if (!cpus)
+        if (!cpus) {
+                spin_unlock(&call_lock);
                 return 0;
+        }
 
         data.func = func;
         data.info = info;
@@ -395,43 +399,14 @@ static int __smp_call_function_mask(cpumask_t mask,
         while (atomic_read(&data.started) != cpus)
                 cpu_relax();
 
-        if (!wait)
-                return 0;
+        if (wait)
+                 while (atomic_read(&data.finished) != cpus)
+                        cpu_relax();
 
-        while (atomic_read(&data.finished) != cpus)
-                cpu_relax();
+        spin_unlock(&call_lock);
 
         return 0;
 }
-/**
- * smp_call_function_mask(): Run a function on a set of other CPUs.
- * @mask: The set of cpus to run on.  Must not include the current cpu.
- * @func: The function to run. This must be fast and non-blocking.
- * @info: An arbitrary pointer to pass to the function.
- * @wait: If true, wait (atomically) until function has completed on other CPUs.
- *
- * Returns 0 on success, else a negative status code.
- *
- * If @wait is true, then returns once @func has returned; otherwise
- * it returns just before the target cpu calls @func.
- *
- * You must not call this function with disabled interrupts or from a
- * hardware interrupt handler or from a bottom half handler.
- */
-int native_smp_call_function_mask(cpumask_t mask,
-                                  void (*func)(void *), void *info,
-                                  int wait)
-{
-        int ret;
-
-        /* Can deadlock when called with interrupts disabled */
-        WARN_ON(irqs_disabled());
-
-        spin_lock(&call_lock);
-        ret = __smp_call_function_mask(mask, func, info, wait);
-        spin_unlock(&call_lock);
-        return ret;
-}
 
 static void stop_this_cpu(void *dummy)
 {