On 08/05/2015 08:11 AM, check.ker...@gmail.com wrote:
> From: yangdongdong <yangdongd...@xiaomi.com>
>
> This also enables panic and oops messages which
> in suspend context to be logged into ramoops console
> buffer where it can be read back at some later point.
>
> Signed-off-by: yangdongdong <yangdongd...@xiaomi.com>
> Signed-off-by: gulinghua <guling...@xiaomi.com>
I have a small comment on the code below.
-Alex
> ---
> fs/pstore/ram.c | 21 +++++++++++++++++++++
> include/linux/pstore_ram.h | 1 +
> kernel/printk/printk.c | 6 ++++++
> 3 files changed, 28 insertions(+)
>
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index 6c26c4d..f84c5ab 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -642,8 +642,28 @@ static void ramoops_register_dummy(void)
> }
> }
>
> +static int ramoops_console_notify(struct notifier_block *this,
> + unsigned long event, void *ptr)
> +{
> + pr_emerg("ramoops unlock console ...\n");
> + emergency_unlock_console();
> +
> + return 0;
> +}
> +
> +static struct notifier_block ramoop_nb = {
> + .notifier_call = ramoops_console_notify,
> + .priority = INT_MAX,
> +};
> +
> +static void ramoops_prepare(void)
> +{
> + atomic_notifier_chain_register(&panic_notifier_list, &ramoop_nb);
> +}
> +
> static int __init ramoops_init(void)
> {
> + ramoops_prepare();
> ramoops_register_dummy();
> return platform_driver_register(&ramoops_driver);
> }
> @@ -654,6 +674,7 @@ static void __exit ramoops_exit(void)
> platform_driver_unregister(&ramoops_driver);
> platform_device_unregister(dummy);
> kfree(dummy_data);
> + atomic_notifier_chain_unregister(&panic_notifier_list, &ramoop_nb);
I would say either wrap this atomic_notificer_chain_unregister()
call in a trivial function ramoops_unprepare(), or (preferably)
get rid of ramoops_prepare().
> }
> module_exit(ramoops_exit);
>
> diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
> index 9c9d6c1..826a35b 100644
> --- a/include/linux/pstore_ram.h
> +++ b/include/linux/pstore_ram.h
> @@ -52,6 +52,7 @@ struct persistent_ram_zone {
> size_t old_log_size;
> };
>
> +extern void emergency_unlock_console(void);
> struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t
> size,
> u32 sig, struct persistent_ram_ecc_info *ecc_info,
> unsigned int memtype);
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index cf8c242..ece645c 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2107,6 +2107,12 @@ void resume_console(void)
> console_unlock();
> }
>
> +void emergency_unlock_console(void)
> +{
> + resume_console();
> +}
> +EXPORT_SYMBOL(emergency_unlock_console);
> +
> /**
> * console_cpu_notify - print deferred console messages after CPU hotplug
> * @self: notifier struct
>
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