On 2021/3/13 3:58, Mike Kravetz wrote:
> On 3/8/21 3:28 AM, Miaohe Lin wrote:
>> Rework the error handling code when alloc_huge_page() failed to remove some
>> duplicated code and simplify the code slightly.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>> ---
>> mm/hugetlb.c | 9 +++------
>> 1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>> index 695603071f2c..69b8de866a24 100644
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -4337,13 +4337,10 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
>> * sure there really is no pte entry.
>> */
>> ptl = huge_pte_lock(h, mm, ptep);
>> - if (!huge_pte_none(huge_ptep_get(ptep))) {
>> - ret = 0;
>> - spin_unlock(ptl);
>> - goto out;
>> - }
>> + ret = 0;
>> + if (huge_pte_none(huge_ptep_get(ptep)))
>> + ret = vmf_error(PTR_ERR(page));
>
> This new code is simpler.
>
> The !huge_pte_none() catches an unlikely race. IMO, the existing code
> made that very clear. Would have been even more clear with an unlikely
> modifier. In any case, the lengthy comment above this code makes it
> clear why the check is there. Code changes are fine.
>
Yep, the lengthy comment above this code makes it much clear why we need the check.
Thanks for carefully review! :)
> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
>
