@@ -627,6 +627,43 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
INIT_LIST_HEAD(&vma->anon_vma_chain);
}
+/* Use when VMA is not part of the VMA tree and needs no locking */
+static inline void init_vm_flags(struct vm_area_struct *vma,
+ unsigned long flags)
+{
+ vma->vm_flags = flags;
+}
+
+/* Use when VMA is part of the VMA tree and modifications need coordination */
+static inline void reset_vm_flags(struct vm_area_struct *vma,
+ unsigned long flags)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ init_vm_flags(vma, flags);
+}
+
+static inline void set_vm_flags(struct vm_area_struct *vma,
+ unsigned long flags)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ vma->vm_flags |= flags;
+}
+
+static inline void clear_vm_flags(struct vm_area_struct *vma,
+ unsigned long flags)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ vma->vm_flags &= ~flags;
+}
+
+static inline void mod_vm_flags(struct vm_area_struct *vma,
+ unsigned long set, unsigned long clear)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ vma->vm_flags |= set;
+ vma->vm_flags &= ~clear;
+}
+
static inline void vma_set_anonymous(struct vm_area_struct *vma)
{
vma->vm_ops = NULL;
@@ -491,7 +491,13 @@ struct vm_area_struct {
* See vmf_insert_mixed_prot() for discussion.
*/
pgprot_t vm_page_prot;
- unsigned long vm_flags; /* Flags, see mm.h. */
+
+ /*
+ * Flags, see mm.h.
+ * WARNING! Do not modify directly.
+ * Use {init|reset|set|clear|mod}_vm_flags() functions instead.
+ */
+ unsigned long vm_flags;
/*
* For areas with an address space and backing store,
vm_flags are among VMA attributes which affect decisions like VMA merging and splitting. Therefore all vm_flags modifications are performed after taking exclusive mmap_lock to prevent vm_flags updates racing with such operations. Introduce modifier functions for vm_flags to be used whenever flags are updated. This way we can better check and control correct locking behavior during these updates. Signed-off-by: Suren Baghdasaryan <surenb@google.com> --- include/linux/mm.h | 37 +++++++++++++++++++++++++++++++++++++ include/linux/mm_types.h | 8 +++++++- 2 files changed, 44 insertions(+), 1 deletion(-)