[tip:core/mutexes] mutex: Add more tests to lib/locking-selftest.c

From: tip-bot for Maarten Lankhorst
Date: Wed Jun 26 2013 - 08:04:59 EST


Commit-ID: 2fe3d4b149ccebbb384062fbbe6634439f2bf120
Gitweb: http://git.kernel.org/tip/2fe3d4b149ccebbb384062fbbe6634439f2bf120
Author: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxx>
AuthorDate: Thu, 20 Jun 2013 13:31:30 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 26 Jun 2013 12:10:57 +0200

mutex: Add more tests to lib/locking-selftest.c

None of the ww_mutex codepaths should be taken in the 'normal'
mutex calls. The easiest way to verify this is by using the
normal mutex calls, and making sure o.ctx is unmodified.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linaro-mm-sig@xxxxxxxxxxxxxxxx
Cc: robclark@xxxxxxxxx
Cc: rostedt@xxxxxxxxxxx
Cc: daniel@xxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20130620113130.4001.45423.stgit@patser
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
lib/locking-selftest.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 9962262..37faefd 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -1162,6 +1162,67 @@ static void ww_test_fail_acquire(void)
#endif
}

+static void ww_test_normal(void)
+{
+ int ret;
+
+ WWAI(&t);
+
+ /*
+ * None of the ww_mutex codepaths should be taken in the 'normal'
+ * mutex calls. The easiest way to verify this is by using the
+ * normal mutex calls, and making sure o.ctx is unmodified.
+ */
+
+ /* mutex_lock (and indirectly, mutex_lock_nested) */
+ o.ctx = (void *)~0UL;
+ mutex_lock(&o.base);
+ mutex_unlock(&o.base);
+ WARN_ON(o.ctx != (void *)~0UL);
+
+ /* mutex_lock_interruptible (and *_nested) */
+ o.ctx = (void *)~0UL;
+ ret = mutex_lock_interruptible(&o.base);
+ if (!ret)
+ mutex_unlock(&o.base);
+ else
+ WARN_ON(1);
+ WARN_ON(o.ctx != (void *)~0UL);
+
+ /* mutex_lock_killable (and *_nested) */
+ o.ctx = (void *)~0UL;
+ ret = mutex_lock_killable(&o.base);
+ if (!ret)
+ mutex_unlock(&o.base);
+ else
+ WARN_ON(1);
+ WARN_ON(o.ctx != (void *)~0UL);
+
+ /* trylock, succeeding */
+ o.ctx = (void *)~0UL;
+ ret = mutex_trylock(&o.base);
+ WARN_ON(!ret);
+ if (ret)
+ mutex_unlock(&o.base);
+ else
+ WARN_ON(1);
+ WARN_ON(o.ctx != (void *)~0UL);
+
+ /* trylock, failing */
+ o.ctx = (void *)~0UL;
+ mutex_lock(&o.base);
+ ret = mutex_trylock(&o.base);
+ WARN_ON(ret);
+ mutex_unlock(&o.base);
+ WARN_ON(o.ctx != (void *)~0UL);
+
+ /* nest_lock */
+ o.ctx = (void *)~0UL;
+ mutex_lock_nest_lock(&o.base, &t);
+ mutex_unlock(&o.base);
+ WARN_ON(o.ctx != (void *)~0UL);
+}
+
static void ww_test_two_contexts(void)
{
WWAI(&t);
@@ -1415,6 +1476,7 @@ static void ww_tests(void)

print_testname("ww api failures");
dotest(ww_test_fail_acquire, SUCCESS, LOCKTYPE_WW);
+ dotest(ww_test_normal, SUCCESS, LOCKTYPE_WW);
dotest(ww_test_unneeded_slow, FAILURE, LOCKTYPE_WW);
printk("\n");

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