ring-buffer: use generic version of in_nmi

[linux-2.6-block.git] / kernel / trace / ring_buffer.c

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index a60a6a852f4285a15191f5b9bbfa34f661ade832..5ee344417cd50b627202ee2b04adffbbad85b453 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -8,6 +8,7 @@
 #include <linux/spinlock.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
+#include <linux/hardirq.h>
 #include <linux/module.h>
 #include <linux/percpu.h>
 #include <linux/mutex.h>
@@ -19,35 +20,6 @@
 
 #include "trace.h"
 
-/*
- * Since the write to the buffer is still not fully lockless,
- * we must be careful with NMIs. The locks in the writers
- * are taken when a write crosses to a new page. The locks
- * protect against races with the readers (this will soon
- * be fixed with a lockless solution).
- *
- * Because we can not protect against NMIs, and we want to
- * keep traces reentrant, we need to manage what happens
- * when we are in an NMI.
- */
-static DEFINE_PER_CPU(int, rb_in_nmi);
-
-void ftrace_nmi_enter(void)
-{
-       __get_cpu_var(rb_in_nmi)++;
-       /* call arch specific handler too */
-       arch_ftrace_nmi_enter();
-}
-
-void ftrace_nmi_exit(void)
-{
-       arch_ftrace_nmi_exit();
-       __get_cpu_var(rb_in_nmi)--;
-       /* NMIs are not recursive */
-       WARN_ON_ONCE(__get_cpu_var(rb_in_nmi));
-}
-
-
 /*
  * A fast way to enable or disable all ring buffers is to
  * call tracing_on or tracing_off. Turning off the ring buffers
@@ -1027,12 +999,23 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 
                local_irq_save(flags);
                /*
+                * Since the write to the buffer is still not
+                * fully lockless, we must be careful with NMIs.
+                * The locks in the writers are taken when a write
+                * crosses to a new page. The locks protect against
+                * races with the readers (this will soon be fixed
+                * with a lockless solution).
+                *
+                * Because we can not protect against NMIs, and we
+                * want to keep traces reentrant, we need to manage
+                * what happens when we are in an NMI.
+                *
                 * NMIs can happen after we take the lock.
                 * If we are in an NMI, only take the lock
                 * if it is not already taken. Otherwise
                 * simply fail.
                 */
-               if (unlikely(__get_cpu_var(rb_in_nmi))) {
+               if (unlikely(in_nmi())) {
                        if (!__raw_spin_trylock(&cpu_buffer->lock))
                                goto out_unlock;
                } else