On Tue, Jan 21, 2020 at 09:53:26AM +0800, Wei Yang wrote:
>On Sun, Jan 19, 2020 at 02:57:53PM +0800, Wei Yang wrote:
>>If we get here after successfully adding page to list, err would be
>>1 to indicate the page is queued in the list.
>>
>>Current code has two problems:
>>
>> * on success, 0 is not returned
>> * on error, if add_page_for_migratioin() return 1, and the following err1
>> from do_move_pages_to_node() is set, the err1 is not returned since err
>> is 1
>>
>>And these behaviors break the user interface.
>>
>>Fixes: e0153fc2c760 ("mm: move_pages: return valid node id in status if the
>>page is already on the target node").
>>Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>>
>>---
>>v2:
>> * put more words to explain the error case
>>---
>> mm/migrate.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>>diff --git a/mm/migrate.c b/mm/migrate.c
>>index 86873b6f38a7..430fdccc733e 100644
>>--- a/mm/migrate.c
>>+++ b/mm/migrate.c
>>@@ -1676,7 +1676,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>> err1 = do_move_pages_to_node(mm, &pagelist, current_node);
>> if (!err1)
>> err1 = store_status(status, start, current_node, i - start);
>>- if (!err)
>>+ if (err >= 0)
>> err = err1;
>
>Ok, as mentioned by Yang and Michal, only err == 0 means no error.
>
>Sounds this regression should be fixed in another place. Let me send out
>another patch.
>
Hmm... I took another look into the case, this fix should work.
But yes, the semantic here is a little confusion. Look forward your comments
here.
>> out:
>> return err;
>>--
>>2.17.1
>
>--
>Wei Yang
>Help you, Help me
--
Wei Yang
Help you, Help me
