[PATCH 3/3] x86: oprofile: fix oprofile_arch_init behaviour on failure

[Will Deacon]

The OProfile driver no longer calls oprofile_arch_exit when
oprofile_arch_init return failure.

This patch fixes the x86 implementation of oprofile_arch_init
to ensure that op_nmi_exit is called if necessary.

Cc: Robert Richter <robert.richter@xxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
---
 arch/x86/oprofile/init.c |   26 +++++++++++++++-----------
 1 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/arch/x86/oprofile/init.c b/arch/x86/oprofile/init.c
index cdfe4c5..886b2c4 100644
--- a/arch/x86/oprofile/init.c
+++ b/arch/x86/oprofile/init.c
@@ -16,34 +16,38 @@
  * with the NMI mode driver.
  */
 
+#ifdef CONFIG_X86_LOCAL_APIC
 extern int op_nmi_init(struct oprofile_operations *ops);
-extern int op_nmi_timer_init(struct oprofile_operations *ops);
 extern void op_nmi_exit(void);
-extern void x86_backtrace(struct pt_regs * const regs, unsigned int depth);
+#else
+static int op_nmi_init(struct oprofile_operations *ops) { return -ENODEV; }
+static void op_nmi_exit(void) {}
+#endif
 
+extern int op_nmi_timer_init(struct oprofile_operations *ops);
+extern void x86_backtrace(struct pt_regs * const regs, unsigned int depth);
 
 int __init oprofile_arch_init(struct oprofile_operations *ops)
 {
 	int ret;
 
-	ret = -ENODEV;
-
-#ifdef CONFIG_X86_LOCAL_APIC
 	ret = op_nmi_init(ops);
-#endif
-#ifdef CONFIG_X86_IO_APIC
 	if (ret < 0)
+#ifdef CONFIG_X86_IO_APIC
 		ret = op_nmi_timer_init(ops);
+#else
+		return ret;
 #endif
+
 	ops->backtrace = x86_backtrace;
 
+	if (ret < 0)
+		op_nmi_exit();
+
 	return ret;
 }
 
-
-void oprofile_arch_exit(void)
+void __exit oprofile_arch_exit(void)
 {
-#ifdef CONFIG_X86_LOCAL_APIC
 	op_nmi_exit();
-#endif
 }
-- 
1.6.3.3

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