Commit 643aa36e authored by Wei Yang's avatar Wei Yang Committed by Linus Torvalds
Browse files

userfaultfd: wrap the common dst_vma check into an inlined function 

When doing UFFDIO_COPY, it is necessary to find the correct destination
vma and make sure fault range is in it.

Since there are two places need to do the same task, just wrap those
common check into an inlined function.

Link: http://lkml.kernel.org/r/20190927070032.2129-3-richardw.yang@linux.intel.com


Signed-off-by: default avatarWei Yang <richardw.yang@linux.intel.com>
Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 53eaa14b

mm/userfaultfd.c

+32 −24
Original line number Diff line number Diff line
@@ -18,6 +18,36 @@ 
#include <asm/tlbflush.h>

#include "internal.h"



static __always_inline

struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm,

				    unsigned long dst_start,

				    unsigned long len)

{

	/*

	 * Make sure that the dst range is both valid and fully within a

	 * single existing vma.

	 */

	struct vm_area_struct *dst_vma;



	dst_vma = find_vma(dst_mm, dst_start);

	if (!dst_vma)

		return NULL;



	if (dst_start < dst_vma->vm_start ||

	    dst_start + len > dst_vma->vm_end)

		return NULL;



	/*

	 * Check the vma is registered in uffd, this is required to

	 * enforce the VM_MAYWRITE check done at uffd registration

	 * time.

	 */

	if (!dst_vma->vm_userfaultfd_ctx.ctx)

		return NULL;



	return dst_vma;

}



static int mcopy_atomic_pte(struct mm_struct *dst_mm,

			    pmd_t *dst_pmd,

			    struct vm_area_struct *dst_vma,
@@ -220,20 +250,9 @@ retry: 
	 */

	if (!dst_vma) {

		err = -ENOENT;

		dst_vma = find_vma(dst_mm, dst_start);

		dst_vma = find_dst_vma(dst_mm, dst_start, len);

		if (!dst_vma || !is_vm_hugetlb_page(dst_vma))

			goto out_unlock;

		/*

		 * Check the vma is registered in uffd, this is

		 * required to enforce the VM_MAYWRITE check done at

		 * uffd registration time.

		 */

		if (!dst_vma->vm_userfaultfd_ctx.ctx)

			goto out_unlock;



		if (dst_start < dst_vma->vm_start ||

		    dst_start + len > dst_vma->vm_end)

			goto out_unlock;



		err = -EINVAL;

		if (vma_hpagesize != vma_kernel_pagesize(dst_vma))
@@ -468,20 +487,9 @@ retry: 
	 * both valid and fully within a single existing vma.

	 */

	err = -ENOENT;

	dst_vma = find_vma(dst_mm, dst_start);

	dst_vma = find_dst_vma(dst_mm, dst_start, len);

	if (!dst_vma)

		goto out_unlock;

	/*

	 * Check the vma is registered in uffd, this is required to

	 * enforce the VM_MAYWRITE check done at uffd registration

	 * time.

	 */

	if (!dst_vma->vm_userfaultfd_ctx.ctx)

		goto out_unlock;



	if (dst_start < dst_vma->vm_start ||

	    dst_start + len > dst_vma->vm_end)

		goto out_unlock;



	err = -EINVAL;

	/*

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