smp: quit unconditionally enabling irq in on_each_cpu_mask and on_each_cpu_cond

As in commit f21afc25f9ed ("smp.h: Use local_irq_{save,restore}() in
!SMP version of on_each_cpu()"), we don't want to enable irqs if they
are not already enabled.  There are currently no known problematical
callers of these functions, but since it is a known failure pattern, we
preemptively fix them.

Since they are not trivial functions, make them non-inline by moving
them to up.c.  This also makes it so we don't have to fix #include
dependancies for preempt_{disable,enable}.

Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 39 insertions, 0 deletions

diff --git a/kernel/up.c b/kernel/up.c
index c54c75e9faf7..144e57255234 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -19,3 +19,42 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
         return 0;
 }
 EXPORT_SYMBOL(smp_call_function_single);
+
+/*
+ * Note we still need to test the mask even for UP
+ * because we actually can get an empty mask from
+ * code that on SMP might call us without the local
+ * CPU in the mask.
+ */
+void on_each_cpu_mask(const struct cpumask *mask,
+                      smp_call_func_t func, void *info, bool wait)
+{
+        unsigned long flags;
+
+        if (cpumask_test_cpu(0, mask)) {
+                local_irq_save(flags);
+                func(info);
+                local_irq_restore(flags);
+        }
+}
+EXPORT_SYMBOL(on_each_cpu_mask);
+
+/*
+ * Preemption is disabled here to make sure the cond_func is called under the
+ * same condtions in UP and SMP.
+ */
+void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
+                      smp_call_func_t func, void *info, bool wait,
+                      gfp_t gfp_flags)
+{
+        unsigned long flags;
+
+        preempt_disable();
+        if (cond_func(0, info)) {
+                local_irq_save(flags);
+                func(info);
+                local_irq_restore(flags);
+        }
+        preempt_enable();
+}
+EXPORT_SYMBOL(on_each_cpu_cond);