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-rw-r--r--mm/ksm.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 3bd54ce9eb38..e11e7a5ac84f 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -32,7 +32,6 @@
#include <linux/mmu_notifier.h>
#include <linux/ksm.h>
-#include <asm/tlb.h>
#include <asm/tlbflush.h>
/*
@@ -285,6 +284,19 @@ static inline int in_stable_tree(struct rmap_item *rmap_item)
}
/*
+ * ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's
+ * page tables after it has passed through ksm_exit() - which, if necessary,
+ * takes mmap_sem briefly to serialize against them. ksm_exit() does not set
+ * a special flag: they can just back out as soon as mm_users goes to zero.
+ * ksm_test_exit() is used throughout to make this test for exit: in some
+ * places for correctness, in some places just to avoid unnecessary work.
+ */
+static inline bool ksm_test_exit(struct mm_struct *mm)
+{
+ return atomic_read(&mm->mm_users) == 0;
+}
+
+/*
* We use break_ksm to break COW on a ksm page: it's a stripped down
*
* if (get_user_pages(current, mm, addr, 1, 1, 1, &page, NULL) == 1)