On 2021/6/18 10:42, Nathan Chancellor wrote:
> On 6/17/2021 7:28 PM, Miaohe Lin wrote:
>> Hi:
>> On 2021/6/18 8:44, Nathan Chancellor wrote:
>>> On Tue, Jun 08, 2021 at 07:45:15PM +0800, Miaohe Lin wrote:
>>>> The zbud doesn't need to export any API and it is meant to be used via
>>>> zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use
>>>> zpool"). So we can remove the unneeded zbud.h and move down zpool API
>>>> to avoid any forward declaration.
>>>>
>>>> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>>>
>>
>> Thank you for help figure these warnings out. It seems zbud module won't do
>> anything when CONFIG_ZPOOL is disabled. I think we should make zbud depends
>> on ZPOOL and eliminate the CONFIG_ZPOOL macro in zbud.c like what z3fold does.
>> Does this make sense for you?
>> Thanks again. :)
>
> That seems logical to me. It probably makes sense to send that as a fix patch for this one so Andrew can squash it in.
Sure. This is also what I meant to do. Will do it later.
Many thanks!
>
> Cheers,
> Nathan
>
>> diff --git a/mm/Kconfig b/mm/Kconfig
>> index 8f748010f7ea..5dc28e9205e0 100644
>> --- a/mm/Kconfig
>> +++ b/mm/Kconfig
>> @@ -674,6 +674,7 @@ config ZPOOL
>>
>> config ZBUD
>> tristate "Low (Up to 2x) density storage for compressed pages"
>> + depends on ZPOOL
>> help
>> A special purpose allocator for storing compressed pages.
>> It is designed to store up to two compressed pages per physical
>> diff --git a/mm/zbud.c b/mm/zbud.c
>> index 3f61304405cb..6348932430b8 100644
>> --- a/mm/zbud.c
>> +++ b/mm/zbud.c
>> @@ -111,10 +111,8 @@ struct zbud_pool {
>> struct list_head lru;
>> u64 pages_nr;
>> const struct zbud_ops *ops;
>> -#ifdef CONFIG_ZPOOL
>> struct zpool *zpool;
>> const struct zpool_ops *zpool_ops;
>> -#endif
>> };
>>
>> /*
>> @@ -526,8 +524,6 @@ static u64 zbud_get_pool_size(struct zbud_pool *pool)
>> * zpool
>> ****************/
>>
>> -#ifdef CONFIG_ZPOOL
>> -
>> static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
>> {
>> if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
>> @@ -618,7 +614,6 @@ static struct zpool_driver zbud_zpool_driver = {
>> };
>>
>> MODULE_ALIAS("zpool-zbud");
>> -#endif /* CONFIG_ZPOOL */
>>
>> static int __init init_zbud(void)
>> {
>> @@ -626,19 +621,14 @@ static int __init init_zbud(void)
>> BUILD_BUG_ON(sizeof(struct zbud_header) > ZHDR_SIZE_ALIGNED);
>> pr_info("loaded\n");
>>
>> -#ifdef CONFIG_ZPOOL
>> zpool_register_driver(&zbud_zpool_driver);
>> -#endif
>>
>> return 0;
>> }
>>
>> static void __exit exit_zbud(void)
>> {
>> -#ifdef CONFIG_ZPOOL
>> zpool_unregister_driver(&zbud_zpool_driver);
>> -#endif
>> -
>> pr_info("unloaded\n");
>> }
>>
>>> This patch causes several new warnings when CONFIG_ZPOOL is disabled:
>>>
>>> mm/zbud.c:222:26: warning: unused function 'zbud_create_pool' [-Wunused-function]
>>> mm/zbud.c:246:13: warning: unused function 'zbud_destroy_pool' [-Wunused-function]
>>> mm/zbud.c:270:12: warning: unused function 'zbud_alloc' [-Wunused-function]
>>> mm/zbud.c:345:13: warning: unused function 'zbud_free' [-Wunused-function]
>>> mm/zbud.c:417:12: warning: unused function 'zbud_reclaim_page' [-Wunused-function]
>>> mm/zbud.c:499:14: warning: unused function 'zbud_map' [-Wunused-function]
>>> mm/zbud.c:509:13: warning: unused function 'zbud_unmap' [-Wunused-function]
>>> mm/zbud.c:520:12: warning: unused function 'zbud_get_pool_size' [-Wunused-function]
>>>
>>> It seems to me like all of these functions should be sunk into their
>>> callers and eliminated entirely as part of this refactoring. I took a
>>> whack at it but got lost with the kernel docs so someone who is familiar
>>> with this should probably do it.
>>>
>>> Cheers,
>>> Nathan
>>> .
>>>
>>
>
> .
