Re: [PATCH v4 3/5] mm, thp: introduce FOLL_SPLIT_PMD

[Song Liu]

> On Jun 21, 2019, at 5:44 AM, Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote:
> 
> On Thu, Jun 13, 2019 at 10:57:45AM -0700, Song Liu wrote:
>> @@ -419,6 +419,11 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
>> 			put_page(page);
>> 			if (pmd_none(*pmd))
>> 				return no_page_table(vma, flags);
>> +		} else {  /* flags & FOLL_SPLIT_PMD */
>> +			spin_unlock(ptl);
>> +			ret = 0;
>> +			split_huge_pmd(vma, pmd, address);
>> +			pte_alloc(mm, pmd);
> 
> pte_alloc() can fail and the failure should be propogated to the caller.

Good catch! Fixing it now. 

Thanks,
Song