[patch 5/5] x86: nmi_watchdog - introduce nmi_watchdog_active() helper

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[patch 5/5] x86: nmi_watchdog - introduce nmi_watchdog_active() helper

Cyrill Gorcunov-2
Signed-off-by: Cyrill Gorcunov <[hidden email]>
---

Index: linux-2.6.git/include/asm-x86/nmi.h
====================================================================
--- linux-2.6.git.orig/include/asm-x86/nmi.h 2008-06-24 19:32:44.000000000 +0400
+++ linux-2.6.git/include/asm-x86/nmi.h 2008-06-24 19:45:13.000000000 +0400
@@ -56,6 +56,19 @@ static inline void localise_nmi_watchdog
  if (nmi_watchdog == NMI_IO_APIC)
  nmi_watchdog = NMI_LOCAL_APIC;
 }
+
+/* check if nmi_watchdog is active (ie was specified at boot) */
+static inline int nmi_watchdog_active(void)
+{
+ /*
+ * actually it should be:
+ * return (nmi_watchdog == NMI_LOCAL_APIC ||
+ * nmi_watchdog == NMI_IO_APIC)
+ * but since they are power of two we could use a
+ * cheaper way --cvg
+ */
+ return nmi_watchdog & 0x3;
+}
 #endif
 
 void lapic_watchdog_stop(void);
Index: linux-2.6.git/arch/x86/kernel/nmi.c
====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/nmi.c 2008-06-24 19:32:09.000000000 +0400
+++ linux-2.6.git/arch/x86/kernel/nmi.c 2008-06-24 19:34:16.000000000 +0400
@@ -116,10 +116,7 @@ int __init check_nmi_watchdog(void)
  unsigned int *prev_nmi_count;
  int cpu;
 
- if (nmi_watchdog == NMI_NONE)
- return 0;
-
- if (!atomic_read(&nmi_active))
+ if (!nmi_watchdog_active() || !atomic_read(&nmi_active))
  return 0;
 
  prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
@@ -316,8 +313,7 @@ void setup_apic_nmi_watchdog(void *unuse
 void stop_apic_nmi_watchdog(void *unused)
 {
  /* only support LOCAL and IO APICs for now */
- if (nmi_watchdog != NMI_LOCAL_APIC &&
-    nmi_watchdog != NMI_IO_APIC)
+ if (!nmi_watchdog_active())
  return;
  if (__get_cpu_var(wd_enabled) == 0)
  return;
@@ -347,8 +343,7 @@ static DEFINE_PER_CPU(int, nmi_touch);
 
 void touch_nmi_watchdog(void)
 {
- if (nmi_watchdog == NMI_LOCAL_APIC ||
- nmi_watchdog == NMI_IO_APIC) {
+ if (nmi_watchdog_active()) {
  unsigned cpu;
 
  /*
@@ -473,7 +468,7 @@ int proc_nmi_enabled(struct ctl_table *t
  if (!!old_state == !!nmi_watchdog_enabled)
  return 0;
 
- if (atomic_read(&nmi_active) < 0 || nmi_watchdog == NMI_NONE) {
+ if (atomic_read(&nmi_active) < 0 || !nmi_watchdog_active()) {
  printk(KERN_WARNING
  "NMI watchdog is permanently disabled\n");
  return -EIO;

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