Allow opportunistic merging of VM_CAN_NONLINEAR areas

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index d3fa10a726cf7446a47a9aebd4db0d1a87b4cca2..c581df14d0de405fc1a2e43b2b939ecb151c5e8a 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -658,6 +658,9 @@ again:                      remove_next = 1 + (end > next->vm_end);
        validate_mm(mm);
 }
 
+/* Flags that can be inherited from an existing mapping when merging */
+#define VM_MERGEABLE_FLAGS (VM_CAN_NONLINEAR)
+
 /*
  * If the vma has a ->close operation then the driver probably needs to release
  * per-vma resources, so we don't attempt to merge those.
@@ -665,7 +668,7 @@ again:                      remove_next = 1 + (end > next->vm_end);
 static inline int is_mergeable_vma(struct vm_area_struct *vma,
                        struct file *file, unsigned long vm_flags)
 {
-       if (vma->vm_flags != vm_flags)
+       if ((vma->vm_flags ^ vm_flags) & ~VM_MERGEABLE_FLAGS)
                return 0;
        if (vma->vm_file != file)
                return 0;