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userfaultfd: introduce vma_can_userfault

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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: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hillf 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Rapoport 2017-02-22 15:43:22 -08:00 committed by Linus Torvalds
parent 163e11bc4f
commit ba6907db6d
1 changed files with 9 additions and 4 deletions
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13
fs/userfaultfd.c
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@ -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