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Diffstat (limited to 'fs/userfaultfd.c')
-rw-r--r--fs/userfaultfd.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 44d1ee429eb0..881e9c82b9d1 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -108,6 +108,21 @@ static bool userfaultfd_is_initialized(struct userfaultfd_ctx *ctx)
return ctx->features & UFFD_FEATURE_INITIALIZED;
}
+/*
+ * Whether WP_UNPOPULATED is enabled on the uffd context. It is only
+ * meaningful when userfaultfd_wp()==true on the vma and when it's
+ * anonymous.
+ */
+bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma)
+{
+ struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
+
+ if (!ctx)
+ return false;
+
+ return ctx->features & UFFD_FEATURE_WP_UNPOPULATED;
+}
+
static void userfaultfd_set_vm_flags(struct vm_area_struct *vma,
vm_flags_t flags)
{
@@ -1971,6 +1986,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
#endif
#ifndef CONFIG_PTE_MARKER_UFFD_WP
uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM;
+ uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED;
#endif
uffdio_api.ioctls = UFFD_API_IOCTLS;
ret = -EFAULT;