diff options
| author | Mike Rapoport <rppt@linux.vnet.ibm.com> | 2017-02-22 15:43:28 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-22 16:41:28 -0800 |
| commit | b0506e488da5cf2f07f3a4f6d7acaa8f459ad714 (patch) | |
| tree | cad7fd2c8c6e3a5d762824925bc6e468dc02ccb6 | |
| parent | 4c27fe4c4c84f3afd504ecff2420cc1ad420d38e (diff) | |
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>
| -rw-r--r-- | include/linux/mm.h | 10 | ||||
| -rw-r--r-- | mm/shmem.c | 5 |
2 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index c3e2be2b3296..bb997493e15d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -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) { diff --git a/mm/shmem.c b/mm/shmem.c index 14de2a9e5083..8412baec17cd 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -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); |