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-rw-r--r--mm/mmap.c41
1 files changed, 27 insertions, 14 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index eeefe19a0fac..a3984fad3fc2 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -181,26 +181,44 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma,
}
/*
- * Remove one vm structure and free it.
+ * Unlink a file-based vm structure from its prio_tree, to hide
+ * vma from rmap and vmtruncate before freeing its page tables.
*/
-static void remove_vm_struct(struct vm_area_struct *vma)
+void unlink_file_vma(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
- might_sleep();
if (file) {
struct address_space *mapping = file->f_mapping;
spin_lock(&mapping->i_mmap_lock);
__remove_shared_vm_struct(vma, file, mapping);
spin_unlock(&mapping->i_mmap_lock);
}
+}
+
+/*
+ * Close a vm structure and free it, returning the next.
+ */
+static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
+{
+ struct vm_area_struct *next = vma->vm_next;
+
+ /*
+ * Hide vma from rmap and vmtruncate before freeing page tables:
+ * to be moved into free_pgtables once page_table_lock is lifted
+ * from it, but until then lock ordering forbids that move.
+ */
+ anon_vma_unlink(vma);
+ unlink_file_vma(vma);
+
+ might_sleep();
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
- if (file)
- fput(file);
- anon_vma_unlink(vma);
+ if (vma->vm_file)
+ fput(vma->vm_file);
mpol_free(vma_policy(vma));
kmem_cache_free(vm_area_cachep, vma);
+ return next;
}
asmlinkage unsigned long sys_brk(unsigned long brk)
@@ -1612,15 +1630,13 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr)
static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
{
do {
- struct vm_area_struct *next = vma->vm_next;
long nrpages = vma_pages(vma);
mm->total_vm -= nrpages;
if (vma->vm_flags & VM_LOCKED)
mm->locked_vm -= nrpages;
vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
- remove_vm_struct(vma);
- vma = next;
+ vma = remove_vma(vma);
} while (vma);
validate_mm(mm);
}
@@ -1944,11 +1960,8 @@ void exit_mmap(struct mm_struct *mm)
* Walk the list again, actually closing and freeing it
* without holding any MM locks.
*/
- while (vma) {
- struct vm_area_struct *next = vma->vm_next;
- remove_vm_struct(vma);
- vma = next;
- }
+ while (vma)
+ vma = remove_vma(vma);
BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
}