Re: [PATCH v2] mm: Fix modifying of page protection by insert_pfn_pmd()

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

On 4/24/19 11:43 PM, Dan Williams wrote:
> On Wed, Apr 24, 2019 at 10:38 AM Matthew Wilcox <willy@infradead.org> wrote:
>>
>> On Wed, Apr 24, 2019 at 10:13:15AM -0700, Dan Williams wrote:
>>> I think unaligned addresses have always been passed to
>>> vmf_insert_pfn_pmd(), but nothing cared until this patch. I *think*
>>> the only change needed is the following, thoughts?
>>>
>>> diff --git a/fs/dax.c b/fs/dax.c
>>> index ca0671d55aa6..82aee9a87efa 100644
>>> --- a/fs/dax.c
>>> +++ b/fs/dax.c
>>> @@ -1560,7 +1560,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct
>>> vm_fault *vmf, pfn_t *pfnp,
>>>                  }
>>>
>>>                  trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry);
>>> -               result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn,
>>> +               result = vmf_insert_pfn_pmd(vma, pmd_addr, vmf->pmd, pfn,
>>>                                              write);
>>
>> We also call vmf_insert_pfn_pmd() in dax_insert_pfn_mkwrite() -- does
>> that need to change too?
> 
> It wasn't clear to me that it was a problem. I think that one already
> happens to be pmd-aligned.
> 

How about vmf_insert_pfn_pud()?

-aneesh