[PATCH 05/21] userfaultfd: add vm_userfaultfd_ctx to the vm_area_struct

Andrea Arcangeli
2015-03-05T17:17:48Z

This adds the vm_userfaultfd_ctx to the vm_area_struct.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
include/linux/mm_types.h | 11 +++++++++++
kernel/fork.c | 1 +
2 files changed, 12 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 199a03a..fbf21f5 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -247,6 +247,16 @@ struct vm_region {
* this region */
};

+#ifdef CONFIG_USERFAULTFD
+#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
+struct vm_userfaultfd_ctx {
+ struct userfaultfd_ctx *ctx;
+};
+#else /* CONFIG_USERFAULTFD */
+#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
+struct vm_userfaultfd_ctx {};
+#endif /* CONFIG_USERFAULTFD */
+
/*
* This struct defines a memory VMM memory area. There is one of these
* per VM-area/task. A VM area is any part of the process virtual memory
@@ -313,6 +323,7 @@ struct vm_area_struct {
#ifdef CONFIG_NUMA
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
#endif
+ struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
};

struct core_thread {
diff --git a/kernel/fork.c b/kernel/fork.c
index cf65139..cb215c0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -425,6 +425,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
goto fail_nomem_anon_vma_fork;
tmp->vm_flags &= ~VM_LOCKED;
tmp->vm_next = tmp->vm_prev = NULL;
+ tmp->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
file = tmp->vm_file;
if (file) {
struct inode *inode = file_inode(file);