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

[Matthew Wilcox]

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?