commit 3ee1afa308f2a38e5d1e2ad3752ad7abcf480da1
author Nick Piggin <npiggin@suse.de> Wed Sep 10 13:37:17 2008 +0200
committer Ingo Molnar <mingo@elte.hu> Thu Sep 11 09:44:21 2008 +0200
tree 914e0f3bbd32a387cf6095c6955369fa8da7ebf6
parent c10d38dda1774ed4540380333cabd229eff37094

x86: some lock annotations for user copy paths, v2

 - introduce might_fault()
 - handle the atomic user copy paths correctly

[ mingo@elte.hu: move might_sleep() outside of in_atomic(). ]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

mm/memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 1002f47..b8fdf4e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3016,3 +3016,18 @@
 	}
 	up_read(&current->mm->mmap_sem);
 }
+
+#ifdef CONFIG_PROVE_LOCKING
+void might_fault(void)
+{
+	might_sleep();
+	/*
+	 * it would be nicer only to annotate paths which are not under
+	 * pagefault_disable, however that requires a larger audit and
+	 * providing helpers like get_user_atomic.
+	 */
+	if (!in_atomic() && current->mm)
+		might_lock_read(&current->mm->mmap_sem);
+}
+EXPORT_SYMBOL(might_fault);
+#endif