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-rw-r--r--mm/mmap.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index d3fa10a726cf..c581df14d0de 100644
--- 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;