userfaultfd: shmem: introduce vma_is_shmem
Currently userfault relies on vma_is_anonymous and vma_is_hugetlb to ensure compatibility of a VMA with userfault. Introduction of vma_is_shmem allows detection if tmpfs backed VMAs, so that they may be used with userfaultfd. Current implementation presumes usage of vma_is_shmem only by slow path routines in userfaultfd, therefore the vma_is_shmem is not made inline to leave the few remaining free bits in vm_flags. Link: http://lkml.kernel.org/r/20161216144821.5183-30-aarcange@redhat.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.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:
parent
4c27fe4c4c
commit
b0506e488d
|
@ -1383,6 +1383,16 @@ static inline bool vma_is_anonymous(struct vm_area_struct *vma)
|
|||
return !vma->vm_ops;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_SHMEM
|
||||
/*
|
||||
* The vma_is_shmem is not inline because it is used only by slow
|
||||
* paths in userfault.
|
||||
*/
|
||||
bool vma_is_shmem(struct vm_area_struct *vma);
|
||||
#else
|
||||
static inline bool vma_is_shmem(struct vm_area_struct *vma) { return false; }
|
||||
#endif
|
||||
|
||||
static inline int stack_guard_page_start(struct vm_area_struct *vma,
|
||||
unsigned long addr)
|
||||
{
|
||||
|
|
|
@ -191,6 +191,11 @@ static const struct inode_operations shmem_special_inode_operations;
|
|||
static const struct vm_operations_struct shmem_vm_ops;
|
||||
static struct file_system_type shmem_fs_type;
|
||||
|
||||
bool vma_is_shmem(struct vm_area_struct *vma)
|
||||
{
|
||||
return vma->vm_ops == &shmem_vm_ops;
|
||||
}
|
||||
|
||||
static LIST_HEAD(shmem_swaplist);
|
||||
static DEFINE_MUTEX(shmem_swaplist_mutex);
|
||||
|
||||
|
|
Loading…
Reference in New Issue