[PATCH 4/7]: changes notifier head of diechains and add notify_chain_unregister

[PATCH 4/7]: changes notifier head of diechains and add notify_chain_unregister

[Chandra Seetharaman]

This patch updates the usages of the various die_chains.  It includes the
changes posted by Keith Owens.  Among them is addition of an unregister
routine; with the new fixes unregister will not race with callouts.

Signed-off-by:  Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by:  Alan Stern <stern@rowland.harvard.edu>
-----

 arch/i386/kernel/traps.c     |   16 ++++++++--------
 arch/ia64/kernel/traps.c     |    2 +-
 arch/powerpc/kernel/traps.c  |   16 ++++++++--------
 arch/sparc64/kernel/traps.c  |   17 +++++++++--------
 arch/x86_64/kernel/traps.c   |   17 +++++++++--------
 include/asm-i386/kdebug.h    |    8 +++-----
 include/asm-ia64/kdebug.h    |    2 +-
 include/asm-powerpc/kdebug.h |   10 +++-------
 include/asm-sparc64/kdebug.h |    9 +++------
 include/asm-x86_64/kdebug.h  |   29 ++++++++++++++---------------
 10 files changed, 59 insertions(+), 67 deletions(-)

Index: l2615-rc1-notifiers/include/asm-i386/kdebug.h
===================================================================
--- l2615-rc1-notifiers.orig/include/asm-i386/kdebug.h
+++ l2615-rc1-notifiers/include/asm-i386/kdebug.h
@@ -17,11 +17,9 @@ struct die_args {
 	int signr;
 };
 
-/* Note - you should never unregister because that can race with NMIs.
-   If you really want to do it first unregister - then synchronize_sched - then free.
-  */
-int register_die_notifier(struct notifier_block *nb);
-extern struct notifier_block *i386die_chain;
+extern int register_die_notifier(struct notifier_block *);
+extern int unregister_die_notifier(struct notifier_block *);
+extern struct notifier_head i386die_chain;
 
 
 /* Grossly misnamed. */
Index: l2615-rc1-notifiers/arch/i386/kernel/traps.c
===================================================================
--- l2615-rc1-notifiers.orig/arch/i386/kernel/traps.c
+++ l2615-rc1-notifiers/arch/i386/kernel/traps.c
@@ -92,20 +92,20 @@ asmlinkage void spurious_interrupt_bug(v
 asmlinkage void machine_check(void);
 
 static int kstack_depth_to_print = 24;
-struct notifier_block *i386die_chain;
-static DEFINE_SPINLOCK(die_notifier_lock);
+ATOMIC_NOTIFIER_HEAD(i386die_chain);
 
 int register_die_notifier(struct notifier_block *nb)
 {
-	int err = 0;
-	unsigned long flags;
-	spin_lock_irqsave(&die_notifier_lock, flags);
-	err = notifier_chain_register(&i386die_chain, nb);
-	spin_unlock_irqrestore(&die_notifier_lock, flags);
-	return err;
+	return notifier_chain_register(&i386die_chain, nb);
 }
 EXPORT_SYMBOL(register_die_notifier);
 
+int unregister_die_notifier(struct notifier_block *nb)
+{
+	return notifier_chain_unregister(&i386die_chain, nb);
+}
+EXPORT_SYMBOL(unregister_die_notifier);
+
 static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
 {
 	return	p > (void *)tinfo &&
Index: l2615-rc1-notifiers/include/asm-ia64/kdebug.h
===================================================================
--- l2615-rc1-notifiers.orig/include/asm-ia64/kdebug.h
+++ l2615-rc1-notifiers/include/asm-ia64/kdebug.h
@@ -40,7 +40,7 @@ struct die_args {
 
 extern int register_die_notifier(struct notifier_block *);
 extern int unregister_die_notifier(struct notifier_block *);
-extern struct notifier_block *ia64die_chain;
+extern struct notifier_head ia64die_chain;
 
 enum die_val {
 	DIE_BREAK = 1,
Index: l2615-rc1-notifiers/arch/ia64/kernel/traps.c
===================================================================
--- l2615-rc1-notifiers.orig/arch/ia64/kernel/traps.c
+++ l2615-rc1-notifiers/arch/ia64/kernel/traps.c
@@ -29,7 +29,7 @@ extern spinlock_t timerlist_lock;
 fpswa_interface_t *fpswa_interface;
 EXPORT_SYMBOL(fpswa_interface);
 
-struct notifier_block *ia64die_chain;
+ATOMIC_NOTIFIER_HEAD(ia64die_chain);
 
 int
 register_die_notifier(struct notifier_block *nb)
Index: l2615-rc1-notifiers/include/asm-powerpc/kdebug.h
===================================================================
--- l2615-rc1-notifiers.orig/include/asm-powerpc/kdebug.h
+++ l2615-rc1-notifiers/include/asm-powerpc/kdebug.h
@@ -15,13 +15,9 @@ struct die_args {
 	int signr;
 };
 
-/*
-   Note - you should never unregister because that can race with NMIs.
-   If you really want to do it first unregister - then synchronize_sched -
-   then free.
- */
-int register_die_notifier(struct notifier_block *nb);
-extern struct notifier_block *powerpc_die_chain;
+extern int register_die_notifier(struct notifier_block *);
+extern int unregister_die_notifier(struct notifier_block *);
+extern struct notifier_head powerpc_die_chain;
 
 /* Grossly misnamed. */
 enum die_val {
Index: l2615-rc1-notifiers/arch/powerpc/kernel/traps.c
===================================================================
--- l2615-rc1-notifiers.orig/arch/powerpc/kernel/traps.c
+++ l2615-rc1-notifiers/arch/powerpc/kernel/traps.c
@@ -73,19 +73,19 @@ EXPORT_SYMBOL(__debugger_dabr_match);
 EXPORT_SYMBOL(__debugger_fault_handler);
 #endif
 
-struct notifier_block *powerpc_die_chain;
-static DEFINE_SPINLOCK(die_notifier_lock);
+ATOMIC_NOTIFIER_HEAD(powerpc_die_chain);
 
 int register_die_notifier(struct notifier_block *nb)
 {
-	int err = 0;
-	unsigned long flags;
+	return notifier_chain_register(&powerpc_die_chain, nb);
+}
+EXPORT_SYMBOL(register_die_notifier);
 
-	spin_lock_irqsave(&die_notifier_lock, flags);
-	err = notifier_chain_register(&powerpc_die_chain, nb);
-	spin_unlock_irqrestore(&die_notifier_lock, flags);
-	return err;
+int unregister_die_notifier(struct notifier_block *nb)
+{
+	return notifier_chain_unregister(&powerpc_die_chain, nb);
 }
+EXPORT_SYMBOL(unregister_die_notifier);
 
 /*
  * Trap & Exception support
Index: l2615-rc1-notifiers/include/asm-sparc64/kdebug.h
===================================================================
--- l2615-rc1-notifiers.orig/include/asm-sparc64/kdebug.h
+++ l2615-rc1-notifiers/include/asm-sparc64/kdebug.h
@@ -15,12 +15,9 @@ struct die_args {
 	int signr;
 };
 
-/* Note - you should never unregister because that can race with NMIs.
- * If you really want to do it first unregister - then synchronize_sched
- * - then free.
- */
-int register_die_notifier(struct notifier_block *nb);
-extern struct notifier_block *sparc64die_chain;
+extern int register_die_notifier(struct notifier_block *);
+extern int unregister_die_notifier(struct notifier_block *);
+extern struct notifier_head sparc64die_chain;
 
 extern void bad_trap(struct pt_regs *, long);
 
Index: l2615-rc1-notifiers/arch/sparc64/kernel/traps.c
===================================================================
--- l2615-rc1-notifiers.orig/arch/sparc64/kernel/traps.c
+++ l2615-rc1-notifiers/arch/sparc64/kernel/traps.c
@@ -42,18 +42,19 @@
 #include <linux/kmod.h>
 #endif
 
-struct notifier_block *sparc64die_chain;
-static DEFINE_SPINLOCK(die_notifier_lock);
+ATOMIC_NOTIFIER_HEAD(sparc64die_chain);
 
 int register_die_notifier(struct notifier_block *nb)
 {
-	int err = 0;
-	unsigned long flags;
-	spin_lock_irqsave(&die_notifier_lock, flags);
-	err = notifier_chain_register(&sparc64die_chain, nb);
-	spin_unlock_irqrestore(&die_notifier_lock, flags);
-	return err;
+	return notifier_chain_register(&sparc64die_chain, nb);
 }
+EXPORT_SYMBOL(register_die_notifier);
+
+int unregister_die_notifier(struct notifier_block *nb)
+{
+	return notifier_chain_unregister(&sparc64die_chain, nb);
+}
+EXPORT_SYMBOL(unregister_die_notifier);
 
 /* When an irrecoverable trap occurs at tl > 0, the trap entry
  * code logs the trap state registers at every level in the trap
Index: l2615-rc1-notifiers/include/asm-x86_64/kdebug.h
===================================================================
--- l2615-rc1-notifiers.orig/include/asm-x86_64/kdebug.h
+++ l2615-rc1-notifiers/include/asm-x86_64/kdebug.h
@@ -5,21 +5,20 @@
 
 struct pt_regs;
 
-struct die_args { 
+struct die_args {
 	struct pt_regs *regs;
 	const char *str;
-	long err; 
+	long err;
 	int trapnr;
 	int signr;
-}; 
+};
+
+extern int register_die_notifier(struct notifier_block *);
+extern int unregister_die_notifier(struct notifier_block *);
+extern struct notifier_head die_chain;
 
-/* Note - you should never unregister because that can race with NMIs.
-   If you really want to do it first unregister - then synchronize_sched - then free.
-  */
-int register_die_notifier(struct notifier_block *nb);
-extern struct notifier_block *die_chain;
 /* Grossly misnamed. */
-enum die_val { 
+enum die_val {
 	DIE_OOPS = 1,
 	DIE_INT3,
 	DIE_DEBUG,
@@ -33,13 +32,13 @@ enum die_val { 
 	DIE_CALL,
 	DIE_NMI_IPI,
 	DIE_PAGE_FAULT,
-}; 
-	
+};
+
 static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig)
-{ 
-	struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig }; 
-	return notifier_call_chain(&die_chain, val, &args); 
-} 
+{
+	struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig };
+	return notifier_call_chain(&die_chain, val, &args);
+}
 
 extern int printk_address(unsigned long address);
 extern void die(const char *,struct pt_regs *,long);
Index: l2615-rc1-notifiers/arch/x86_64/kernel/traps.c
===================================================================
--- l2615-rc1-notifiers.orig/arch/x86_64/kernel/traps.c
+++ l2615-rc1-notifiers/arch/x86_64/kernel/traps.c
@@ -72,18 +72,19 @@ asmlinkage void machine_check(void);
 asmlinkage void spurious_interrupt_bug(void);
 asmlinkage void call_debug(void);
 
-struct notifier_block *die_chain;
-static DEFINE_SPINLOCK(die_notifier_lock);
+ATOMIC_NOTIFIER_HEAD(die_chain);
 
 int register_die_notifier(struct notifier_block *nb)
 {
-	int err = 0;
-	unsigned long flags;
-	spin_lock_irqsave(&die_notifier_lock, flags);
-	err = notifier_chain_register(&die_chain, nb);
-	spin_unlock_irqrestore(&die_notifier_lock, flags);
-	return err;
+	return notifier_chain_register(&die_chain, nb);
+}
+EXPORT_SYMBOL(register_die_notifier);
+
+int unregister_die_notifier(struct notifier_block *nb)
+{
+	return notifier_chain_unregister(&die_chain, nb);
 }
+EXPORT_SYMBOL(unregister_die_notifier);
 
 static inline void conditional_sti(struct pt_regs *regs)
 {

-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

Re: [Lse-tech] [PATCH 4/7]: changes notifier head of diechains and add notify_chain_unregister

[Andi Kleen]

> Index: l2615-rc1-notifiers/include/asm-x86_64/kdebug.h
> ===================================================================
> --- l2615-rc1-notifiers.orig/include/asm-x86_64/kdebug.h
> +++ l2615-rc1-notifiers/include/asm-x86_64/kdebug.h
> @@ -5,21 +5,20 @@
>  
>  struct pt_regs;
>  
> -struct die_args { 
> +struct die_args {

etc. lots more occurrences.

Can you please repost the patch without arbitary white space changes
everywhere?  They make it hard to review what you actually changed.

-Andi

Re: [Lse-tech] [PATCH 4/7]: changes notifier head of diechains and add notify_chain_unregister

[Keith Owens]

On Thu, 24 Nov 2005 00:57:28 +0100, 
Andi Kleen <ak@suse.de> wrote:
>> Index: l2615-rc1-notifiers/include/asm-x86_64/kdebug.h
>> ===================================================================
>> --- l2615-rc1-notifiers.orig/include/asm-x86_64/kdebug.h
>> +++ l2615-rc1-notifiers/include/asm-x86_64/kdebug.h
>> @@ -5,21 +5,20 @@
>>  
>>  struct pt_regs;
>>  
>> -struct die_args { 
>> +struct die_args {
>
>etc. lots more occurrences.
>
>Can you please repost the patch without arbitary white space changes
>everywhere?

Not everywhere, only include/asm-x86_64/kdebug.h has trailing white
space and there was not enough white space changes to justify splitting
its change into two patches.  But since you insist ...

White space changes first.

Index: linux/include/asm-x86_64/kdebug.h
===================================================================
--- linux.orig/include/asm-x86_64/kdebug.h	2005-11-25 15:29:33.303590496 +1100
+++ linux/include/asm-x86_64/kdebug.h	2005-11-25 15:29:51.278657263 +1100
@@ -5,13 +5,13 @@
 
 struct pt_regs;
 
-struct die_args { 
+struct die_args {
 	struct pt_regs *regs;
 	const char *str;
-	long err; 
+	long err;
 	int trapnr;
 	int signr;
-}; 
+};
 
 /* Note - you should never unregister because that can race with NMIs.
    If you really want to do it first unregister - then synchronize_sched - then free.
@@ -19,7 +19,7 @@ struct die_args { 
 int register_die_notifier(struct notifier_block *nb);
 extern struct notifier_block *die_chain;
 /* Grossly misnamed. */
-enum die_val { 
+enum die_val {
 	DIE_OOPS = 1,
 	DIE_INT3,
 	DIE_DEBUG,
@@ -33,13 +33,13 @@ enum die_val { 
 	DIE_CALL,
 	DIE_NMI_IPI,
 	DIE_PAGE_FAULT,
-}; 
-	
+};
+
 static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig)
-{ 
-	struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig }; 
-	return notifier_call_chain(&die_chain, val, &args); 
-} 
+{
+	struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig };
+	return notifier_call_chain(&die_chain, val, &args);
+}
 
 extern int printk_address(unsigned long address);
 extern void die(const char *,struct pt_regs *,long);

This is what is really changed in include/asm-x86_64/kdebug.h, the same
basic change as in i386.

Index: linux/include/asm-x86_64/kdebug.h
===================================================================
--- linux.orig/include/asm-x86_64/kdebug.h	2005-10-28 10:02:08.000000000 +1000
+++ linux/include/asm-x86_64/kdebug.h	2005-11-25 15:20:16.553007734 +1100
@@ -13,11 +13,10 @@ struct die_args {
 	int signr;
 };
 
-/* Note - you should never unregister because that can race with NMIs.
-   If you really want to do it first unregister - then synchronize_sched - then free.
-  */
-int register_die_notifier(struct notifier_block *nb);
-extern struct notifier_block *die_chain;
+extern int register_die_notifier(struct notifier_block *);
+extern int unregister_die_notifier(struct notifier_block *);
+extern struct notifier_head die_chain;
+
 /* Grossly misnamed. */
 enum die_val {
 	DIE_OOPS = 1,