[PATCH v9 07/14] smp: Remove preempt_disable() from smp_call_function()

[Chuyi Zhou]

smp_call_function_many_cond() handles the preemption and CPU pinning
requirements internally. smp_call_function() only forwards the request to
that helper for cpu_online_mask and does not access CPU-local state on
its own.

Remove the outer preempt_disable() and preempt_enable() pair from
smp_call_function().

Signed-off-by: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Reviewed-by: Muchun Song <muchun.song@xxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
 kernel/smp.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index 92f984754139..933a14dbb8f8 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -994,10 +994,10 @@ EXPORT_SYMBOL(smp_call_function_many);
 
 /**
  * smp_call_function() - Run a function on all other CPUs.
- * @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.
+ * @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.
  *
  * If @wait is true, then returns once @func has returned; otherwise
  * it returns just before the target cpu calls @func.
@@ -1007,9 +1007,8 @@ EXPORT_SYMBOL(smp_call_function_many);
  */
 void smp_call_function(smp_call_func_t func, void *info, int wait)
 {
-	preempt_disable();
-	smp_call_function_many(cpu_online_mask, func, info, wait);
-	preempt_enable();
+	smp_call_function_many_cond(cpu_online_mask, func, info,
+				    wait ? SCF_WAIT : 0, NULL);
 }
 EXPORT_SYMBOL(smp_call_function);
 
-- 
2.20.1