Re: [PATCH v2 09/26] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers

From: Mike Rapoport <rppt@linux.ibm.com>
To: Peter Xu <peterx@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	David Hildenbrand <david@redhat.com>,
	Hugh Dickins <hughd@google.com>, Maya Gokhale <gokhale2@llnl.gov>,
	Jerome Glisse <jglisse@redhat.com>,
	Pavel Emelyanov <xemul@virtuozzo.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Martin Cracauer <cracauer@cons.org>, Shaohua Li <shli@fb.com>,
	Marty McFadden <mcfadden8@llnl.gov>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Denis Plotnikov <dplotnikov@virtuozzo.com>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Mel Gorman <mgorman@suse.de>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [PATCH v2 09/26] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers
Date: Mon, 25 Feb 2019 19:12:15 +0200	[thread overview]
Message-ID: <20190225171214.GE24917@rapoport-lnx> (raw)
In-Reply-To: <20190212025632.28946-10-peterx@redhat.com>

On Tue, Feb 12, 2019 at 10:56:15AM +0800, Peter Xu wrote:
> From: Andrea Arcangeli <aarcange@redhat.com>
> 
> Implement helpers methods to invoke userfaultfd wp faults more
> selectively: not only when a wp fault triggers on a vma with
> vma->vm_flags VM_UFFD_WP set, but only if the _PAGE_UFFD_WP bit is set
> in the pagetable too.
> 
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>

> ---
>  include/linux/userfaultfd_k.h | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
> index 38f748e7186e..c6590c58ce28 100644
> --- a/include/linux/userfaultfd_k.h
> +++ b/include/linux/userfaultfd_k.h
> @@ -14,6 +14,8 @@
>  #include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
> 
>  #include <linux/fcntl.h>
> +#include <linux/mm.h>
> +#include <asm-generic/pgtable_uffd.h>
> 
>  /*
>   * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
> @@ -55,6 +57,18 @@ static inline bool userfaultfd_wp(struct vm_area_struct *vma)
>  	return vma->vm_flags & VM_UFFD_WP;
>  }
> 
> +static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
> +				      pte_t pte)
> +{
> +	return userfaultfd_wp(vma) && pte_uffd_wp(pte);
> +}
> +
> +static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
> +					   pmd_t pmd)
> +{
> +	return userfaultfd_wp(vma) && pmd_uffd_wp(pmd);
> +}
> +
>  static inline bool userfaultfd_armed(struct vm_area_struct *vma)
>  {
>  	return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
> @@ -104,6 +118,19 @@ static inline bool userfaultfd_wp(struct vm_area_struct *vma)
>  	return false;
>  }
> 
> +static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
> +				      pte_t pte)
> +{
> +	return false;
> +}
> +
> +static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
> +					   pmd_t pmd)
> +{
> +	return false;
> +}
> +
> +
>  static inline bool userfaultfd_armed(struct vm_area_struct *vma)
>  {
>  	return false;
> -- 
> 2.17.1
> 

-- 
Sincerely yours,
Mike.