Hello
2014-11-13 23:22 GMT+08:00 Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>:
> On (11/13/14 21:37), Mahendran Ganesh wrote:
>> Now zsmalloc can be registered as a zpool driver into zpool when
>> CONFIG_ZPOOL is enabled. During the init of zsmalloc, when error happens,
>> we need to do cleanup. But in current code, it will unregister a not yet
>> registered zsmalloc zpool driver(*zs_zpool_driver*).
>>
>> This patch puts the cleanup in zs_init() instead of calling zs_exit()
>> where it will unregister a not-registered zpool driver.
>>
>> Signed-off-by: Mahendran Ganesh <opensource.ganesh@xxxxxxxxx>
>> ---
>> mm/zsmalloc.c | 12 ++++++++----
>> 1 file changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
>> index 839a48c..3d2bb36 100644
>> --- a/mm/zsmalloc.c
>> +++ b/mm/zsmalloc.c
>> @@ -907,10 +907,8 @@ static int zs_init(void)
>> __register_cpu_notifier(&zs_cpu_nb);
>> for_each_online_cpu(cpu) {
>> ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
>> - if (notifier_to_errno(ret)) {
>> - cpu_notifier_register_done();
>> + if (notifier_to_errno(ret))
>> goto fail;
>> - }
>> }
>>
>> cpu_notifier_register_done();
>> @@ -920,8 +918,14 @@ static int zs_init(void)
>> #endif
>>
>> return 0;
>> +
>> fail:
>> - zs_exit();
>> + for_each_online_cpu(cpu)
>> + zs_cpu_notifier(NULL, CPU_UP_CANCELED, (void *)(long)cpu);
>> + __unregister_cpu_notifier(&zs_cpu_nb);
>> +
>> + cpu_notifier_register_done();
>> +
>> return notifier_to_errno(ret);
>
> so we duplicate same code, and there is a bit confusing part
> now: zs_cpu_notifier(CPU_UP_CANCELED) and zs_cpu_notifier(CPU_DEAD)
> calls.
Thanks for your review.
CPU_UP_CANCELED and CPU_DEAD have different scenario.
CPU_UP_CANCELED is better for fail to complete initialization. While
CPU_DEAD is better for exit(such as removing module)
Thanks.
>
> how about something like this?
>
> Factor out zsmalloc cpu notifier unregistration code and call
> it from both zs_exit() and zs_init() error path.
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
>
> ---
>
> mm/zsmalloc.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index b3b57ef..c4d2d60 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -881,14 +881,10 @@ static struct notifier_block zs_cpu_nb = {
> .notifier_call = zs_cpu_notifier
> };
>
> -static void zs_exit(void)
> +static inline void zs_unregister_cpu_notifier()
> {
> int cpu;
>
> -#ifdef CONFIG_ZPOOL
> - zpool_unregister_driver(&zs_zpool_driver);
> -#endif
> -
> cpu_notifier_register_begin();
>
> for_each_online_cpu(cpu)
> @@ -898,6 +894,14 @@ static void zs_exit(void)
> cpu_notifier_register_done();
> }
>
> +static void zs_exit(void)
> +{
> +#ifdef CONFIG_ZPOOL
> + zpool_unregister_driver(&zs_zpool_driver);
> +#endif
> + zs_unregister_cpu_notifier();
> +}
> +
> static int zs_init(void)
> {
> int cpu, ret;
> @@ -907,10 +911,8 @@ static int zs_init(void)
> __register_cpu_notifier(&zs_cpu_nb);
> for_each_online_cpu(cpu) {
> ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
> - if (notifier_to_errno(ret)) {
> - cpu_notifier_register_done();
> + if (notifier_to_errno(ret))
> goto fail;
> - }
> }
>
> cpu_notifier_register_done();
> @@ -921,7 +923,7 @@ static int zs_init(void)
>
> return 0;
> fail:
> - zs_exit();
> + zs_unregister_cpu_notifier();
> return notifier_to_errno(ret);
> }
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>