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authorDave Airlie <airlied@redhat.com>2018-03-28 14:30:41 +1000
committerDave Airlie <airlied@redhat.com>2018-03-28 14:30:41 +1000
commit2b4f44eec2be2688511c2b617d0e1b4f94c45ba4 (patch)
tree533c03602f4ae6d6404db6fa56c88e6f83e1bebe /include/linux/sched/mm.h
parent33d009cd889490838c5db9b9339856c9e3d3facc (diff)
parent3eb2ce825ea1ad89d20f7a3b5780df850e4be274 (diff)
Backmerge tag 'v4.16-rc7' into drm-next
Linux 4.16-rc7 This was requested by Daniel, and things were getting a bit hard to reconcile, most of the conflicts were trivial though.
Diffstat (limited to 'include/linux/sched/mm.h')
-rw-r--r--include/linux/sched/mm.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 1149533aa2fa..9806184bb3d5 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -36,7 +36,18 @@ static inline void mmgrab(struct mm_struct *mm)
atomic_inc(&mm->mm_count);
}
-extern void mmdrop(struct mm_struct *mm);
+extern void __mmdrop(struct mm_struct *mm);
+
+static inline void mmdrop(struct mm_struct *mm)
+{
+ /*
+ * The implicit full barrier implied by atomic_dec_and_test() is
+ * required by the membarrier system call before returning to
+ * user-space, after storing to rq->curr.
+ */
+ if (unlikely(atomic_dec_and_test(&mm->mm_count)))
+ __mmdrop(mm);
+}
/**
* mmget() - Pin the address space associated with a &struct mm_struct.