Re: [PATCH] mm: Fix a race during split THP

[Huang, Ying]

Matthew Wilcox <willy@xxxxxxxxxxxxx> writes:

> On Fri, Oct 09, 2020 at 03:36:47PM +0800, Huang, Ying wrote:
>> +	if (PageSwapCache(head)) {
>> +		swp_entry_t entry = { .val = page_private(head) };
>> +
>> +		split_swap_cluster(entry);
>> +	}
> ...
>> -		if (PageSwapCache(head)) {
>> -			swp_entry_t entry = { .val = page_private(head) };
>> -
>> -			ret = split_swap_cluster(entry);
>
> Are we sure split_swap_cluster() can't fail?  Or if it does fail, it's
> OK to continue with the split and not report the error?

split_swap_cluster() can only fail for invalid swap entry.  Which isn't
expected to happen in this situation.

Best Regards,
Huang, Ying