On Fri, Sep 27, 2019 at 03:21:38PM -0700, Mike Kravetz wrote:
>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. :)
>
I did a cleanup to remove the first parameter of function
hugetlb_fault_mutex_hash(). Look forward your comment.
>You can add,
>Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
>to the series.
>--
>Mike Kravetz
--
Wei Yang
Help you, Help me
