Re: [RFC PATCH v2 1/5] userfaultfd: introduce uffd_flags

[Nadav Amit <namit@vmware.com>]

On Jun 21, 2022, at 8:29 AM, Peter Xu <peterx@redhat.com> wrote:

> ⚠ External Email
> 
> On Sun, Jun 19, 2022 at 04:34:45PM -0700, Nadav Amit wrote:
>> @@ -683,30 +681,33 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
>> 
>> ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
>>                   unsigned long src_start, unsigned long len,
>> -                  atomic_t *mmap_changing, __u64 mode)
>> +                  atomic_t *mmap_changing, uffd_flags_t uffd_flags)
>> {
>>      return __mcopy_atomic(dst_mm, dst_start, src_start, len,
>> -                           MCOPY_ATOMIC_NORMAL, mmap_changing, mode);
>> +                           MCOPY_ATOMIC_NORMAL, mmap_changing, uffd_flags);
>> }
>> 
>> ssize_t mfill_zeropage(struct mm_struct *dst_mm, unsigned long start,
>> -                    unsigned long len, atomic_t *mmap_changing)
>> +                    unsigned long len, atomic_t *mmap_changing,
>> +                    uffd_flags_t uffd_flags)
> 
> Should this be fed into the last parameter of __mcopy_atomic() below?
> 
>> {
>>      return __mcopy_atomic(dst_mm, start, 0, len, MCOPY_ATOMIC_ZEROPAGE,
>>                            mmap_changing, 0);
>> }
>> 
>> ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long start,
>> -                    unsigned long len, atomic_t *mmap_changing)
>> +                    unsigned long len, atomic_t *mmap_changing,
>> +                    uffd_flags_t uffd_flags)
> 
> Same question here..

Yes it should. I think I will add flags for CONTINUE/ZERO ACCESS/WRITE
just for consistency, even if we eventually decide to disregard them.