Re: [PATCH RESEND 1/2] powerpc/mce: Add MCE notification chain

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 09/07/2020 à 09:56, Santosh Sivaraj a écrit :
> Introduce notification chain which lets know about uncorrected memory
> errors(UE). This would help prospective users in pmem or nvdimm subsystem
> to track bad blocks for better handling of persistent memory allocations.
> 
> Signed-off-by: Santosh S <santosh@fossix.org>
> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
> ---
>   arch/powerpc/include/asm/mce.h |  2 ++
>   arch/powerpc/kernel/mce.c      | 15 +++++++++++++++
>   2 files changed, 17 insertions(+)
> 
> Send the two patches together, so the dependencies are clear. The earlier patch reviews are
> here: https://lore.kernel.org/linuxppc-dev/20200330071219.12284-1-ganeshgr@linux.ibm.com/
> 
> Rebase the patches on top on 5.8-rc4
> 
> diff --git a/arch/powerpc/include/asm/mce.h b/arch/powerpc/include/asm/mce.h
> index 376a395daf329..a57b0772702a9 100644
> --- a/arch/powerpc/include/asm/mce.h
> +++ b/arch/powerpc/include/asm/mce.h
> @@ -220,6 +220,8 @@ extern void machine_check_print_event_info(struct machine_check_event *evt,
>   unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr);
>   extern void mce_common_process_ue(struct pt_regs *regs,
>   				  struct mce_error_info *mce_err);
> +extern int mce_register_notifier(struct notifier_block *nb);
> +extern int mce_unregister_notifier(struct notifier_block *nb);

Using the 'extern' keyword on function declaration is pointless and 
should be avoided in new patches. (checkpatch.pl --strict usually 
complains about it).

>   #ifdef CONFIG_PPC_BOOK3S_64
>   void flush_and_reload_slb(void);
>   #endif /* CONFIG_PPC_BOOK3S_64 */
> diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
> index fd90c0eda2290..b7b3ed4e61937 100644
> --- a/arch/powerpc/kernel/mce.c
> +++ b/arch/powerpc/kernel/mce.c
> @@ -49,6 +49,20 @@ static struct irq_work mce_ue_event_irq_work = {
>   
>   DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
>   
> +static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);
> +
> +int mce_register_notifier(struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_register(&mce_notifier_list, nb);
> +}
> +EXPORT_SYMBOL_GPL(mce_register_notifier);
> +
> +int mce_unregister_notifier(struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_unregister(&mce_notifier_list, nb);
> +}
> +EXPORT_SYMBOL_GPL(mce_unregister_notifier);
> +
>   static void mce_set_error_info(struct machine_check_event *mce,
>   			       struct mce_error_info *mce_err)
>   {
> @@ -278,6 +292,7 @@ static void machine_process_ue_event(struct work_struct *work)
>   	while (__this_cpu_read(mce_ue_count) > 0) {
>   		index = __this_cpu_read(mce_ue_count) - 1;
>   		evt = this_cpu_ptr(&mce_ue_event_queue[index]);
> +		blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
>   #ifdef CONFIG_MEMORY_FAILURE
>   		/*
>   		 * This should probably queued elsewhere, but
> 

Christophe