[PATCH 6/9] dma-buf/selftests: test RCU ops and inline lock v2

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Drop the mock_fence and the kmem_cache, instead use the inline lock and
test if the ops are properly dropped after signaling.

v2: move the RCU check to the end of the test

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
---
 drivers/dma-buf/st-dma-fence.c | 44 ++++++++--------------------------
 1 file changed, 10 insertions(+), 34 deletions(-)

diff --git a/drivers/dma-buf/st-dma-fence.c b/drivers/dma-buf/st-dma-fence.c
index 5d0d9abc6e21..0d9d524d79b6 100644
--- a/drivers/dma-buf/st-dma-fence.c
+++ b/drivers/dma-buf/st-dma-fence.c
@@ -14,43 +14,26 @@
 
 #include "selftest.h"
 
-static struct kmem_cache *slab_fences;
-
-static struct mock_fence {
-	struct dma_fence base;
-	struct spinlock lock;
-} *to_mock_fence(struct dma_fence *f) {
-	return container_of(f, struct mock_fence, base);
-}
-
 static const char *mock_name(struct dma_fence *f)
 {
 	return "mock";
 }
 
-static void mock_fence_release(struct dma_fence *f)
-{
-	kmem_cache_free(slab_fences, to_mock_fence(f));
-}
-
 static const struct dma_fence_ops mock_ops = {
 	.get_driver_name = mock_name,
 	.get_timeline_name = mock_name,
-	.release = mock_fence_release,
 };
 
 static struct dma_fence *mock_fence(void)
 {
-	struct mock_fence *f;
+	struct dma_fence *f;
 
-	f = kmem_cache_alloc(slab_fences, GFP_KERNEL);
+	f = kmalloc(sizeof(*f), GFP_KERNEL);
 	if (!f)
 		return NULL;
 
-	spin_lock_init(&f->lock);
-	dma_fence_init(&f->base, &mock_ops, &f->lock, 0, 0);
-
-	return &f->base;
+	dma_fence_init(f, &mock_ops, NULL, 0, 0);
+	return f;
 }
 
 static int sanitycheck(void *arg)
@@ -100,6 +83,11 @@ static int test_signaling(void *arg)
 		goto err_free;
 	}
 
+	if (rcu_dereference_protected(f->ops, true)) {
+		pr_err("Fence ops not cleared on signal\n");
+		goto err_free;
+	}
+
 	err = 0;
 err_free:
 	dma_fence_put(f);
@@ -540,19 +528,7 @@ int dma_fence(void)
 		SUBTEST(test_stub),
 		SUBTEST(race_signal_callback),
 	};
-	int ret;
 
 	pr_info("sizeof(dma_fence)=%zu\n", sizeof(struct dma_fence));
-
-	slab_fences = KMEM_CACHE(mock_fence,
-				 SLAB_TYPESAFE_BY_RCU |
-				 SLAB_HWCACHE_ALIGN);
-	if (!slab_fences)
-		return -ENOMEM;
-
-	ret = subtests(tests, NULL);
-
-	kmem_cache_destroy(slab_fences);
-
-	return ret;
+	return subtests(tests, NULL);
 }
-- 
2.43.0