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Commit ba6907db authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

userfaultfd: introduce vma_can_userfault 

Check whether a VMA can be used with userfault in more compact way

Link: http://lkml.kernel.org/r/20161216144821.5183-28-aarcange@redhat.com


Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Acked-by: default avatarHillf Danton <hillf.zj@alibaba-inc.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 163e11bc

fs/userfaultfd.c

+9 −4
Original line number Original line Diff line number Diff line
@@ -1096,6 +1096,11 @@ static __always_inline int validate_range(struct mm_struct *mm, 
	return 0;

	return 0;

}

}





static inline bool vma_can_userfault(struct vm_area_struct *vma)

{

	return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma);

}



static int userfaultfd_register(struct userfaultfd_ctx *ctx,

static int userfaultfd_register(struct userfaultfd_ctx *ctx,

				unsigned long arg)

				unsigned long arg)

{

{
@@ -1185,7 +1190,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 




		/* check not compatible vmas */

		/* check not compatible vmas */

		ret = -EINVAL;

		ret = -EINVAL;

		if (!vma_is_anonymous(cur) && !is_vm_hugetlb_page(cur))

		if (!vma_can_userfault(cur))

			goto out_unlock;

			goto out_unlock;

		/*

		/*

		 * If this vma contains ending address, and huge pages

		 * If this vma contains ending address, and huge pages
@@ -1229,7 +1234,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 
	do {

	do {

		cond_resched();

		cond_resched();





		BUG_ON(!vma_is_anonymous(vma) && !is_vm_hugetlb_page(vma));

		BUG_ON(!vma_can_userfault(vma));

		BUG_ON(vma->vm_userfaultfd_ctx.ctx &&

		BUG_ON(vma->vm_userfaultfd_ctx.ctx &&

		       vma->vm_userfaultfd_ctx.ctx != ctx);

		       vma->vm_userfaultfd_ctx.ctx != ctx);
@@ -1367,7 +1372,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, 
		 * provides for more strict behavior to notice

		 * provides for more strict behavior to notice

		 * unregistration errors.

		 * unregistration errors.

		 */

		 */

		if (!vma_is_anonymous(cur) && !is_vm_hugetlb_page(cur))

		if (!vma_can_userfault(cur))

			goto out_unlock;

			goto out_unlock;





		found = true;

		found = true;
@@ -1381,7 +1386,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, 
	do {

	do {

		cond_resched();

		cond_resched();





		BUG_ON(!vma_is_anonymous(vma) && !is_vm_hugetlb_page(vma));

		BUG_ON(!vma_can_userfault(vma));





		/*

		/*

		 * Nothing to do: this vma is already registered into this

		 * Nothing to do: this vma is already registered into this