On 9/27/19 3:10 PM, Andrew Morton wrote:
> On Fri, 27 Sep 2019 15:00:30 +0800 Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> wrote:
>
>> In function __mcopy_atomic_hugetlb, we use two variables to deal with
>> huge page size: vma_hpagesize and huge_page_size.
>>
>> Since they are the same, it is not necessary to use two different
>> mechanism. This patch makes it consistent by all using vma_hpagesize.
>>
>> --- a/mm/userfaultfd.c
>> +++ b/mm/userfaultfd.c
>> @@ -262,7 +262,7 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
>> pte_t dst_pteval;
>>
>> BUG_ON(dst_addr >= dst_start + len);
>> - VM_BUG_ON(dst_addr & ~huge_page_mask(h));
>> + VM_BUG_ON(dst_addr & (vma_hpagesize - 1));
>>
>> /*
>> * Serialize via hugetlb_fault_mutex
>> @@ -273,7 +273,7 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
>> mutex_lock(&hugetlb_fault_mutex_table[hash]);
>>
>> err = -ENOMEM;
>> - dst_pte = huge_pte_alloc(dst_mm, dst_addr, huge_page_size(h));
>> + dst_pte = huge_pte_alloc(dst_mm, dst_addr, vma_hpagesize);
>> if (!dst_pte) {
>> mutex_unlock(&hugetlb_fault_mutex_table[hash]);
>> goto out_unlock;
>> @@ -300,7 +300,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
>>
>> err = copy_huge_page_from_user(page,
>> (const void __user *)src_addr,
>> - pages_per_huge_page(h), true);
>> + vma_hpagesize / PAGE_SIZE,
>> + true);
>> if (unlikely(err)) {
>> err = -EFAULT;
>> goto out;
>
> Looks right.
>
> We could go ahead and remove local variable `h', given that
> hugetlb_fault_mutex_hash() doesn't actually use its first arg..
Good catch Andrew. I missed that, but I also wrote the original code that
is being cleaned up. :)
You can add,
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
to the series.
--
Mike Kravetz
