[PATCH 3/3] drm/i915: Markup expected timeline locks for i915_active

Chris Wilson
2019-08-16T09:26:08Z

As every i915_active_request should be serialised by a dedicated lock,
i915_active consists of a tree of locks; one for each node. Markup up
the i915_active_request with what lock is supposed to be guarding it so
that we can verify that the serialised updated are indeed serialised.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/display/intel_overlay.c | 2 +-
.../gpu/drm/i915/gem/i915_gem_client_blt.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_context.c | 2 +-
drivers/gpu/drm/i915/gt/intel_context.c | 11 +++--------
drivers/gpu/drm/i915/gt/intel_engine_pool.h | 2 +-
drivers/gpu/drm/i915/gt/intel_timeline.c | 7 +++----
drivers/gpu/drm/i915/gt/selftest_timeline.c | 4 ++++
.../gpu/drm/i915/gt/selftests/mock_timeline.c | 2 +-
drivers/gpu/drm/i915/i915_active.c | 19 +++++++++++++++----
drivers/gpu/drm/i915/i915_active.h | 12 ++++++++++--
drivers/gpu/drm/i915/i915_active_types.h | 3 +++
drivers/gpu/drm/i915/i915_vma.c | 4 ++--
drivers/gpu/drm/i915/selftests/i915_active.c | 3 +--
13 files changed, 46 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
index e1248eace0e1..eca41c4a5aa6 100644
--- a/drivers/gpu/drm/i915/display/intel_overlay.c
+++ b/drivers/gpu/drm/i915/display/intel_overlay.c
@@ -230,7 +230,7 @@ alloc_request(struct intel_overlay *overlay, void (*fn)(struct intel_overlay *))
if (IS_ERR(rq))
return rq;

- err = i915_active_ref(&overlay->last_flip, rq->fence.context, rq);
+ err = i915_active_ref(&overlay->last_flip, rq->timeline, rq);
if (err) {
i915_request_add(rq);
return ERR_PTR(err);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c b/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c
index 6a4e84157bf2..818ac6915bc5 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_client_blt.c
@@ -211,7 +211,7 @@ static void clear_pages_worker(struct work_struct *work)
* keep track of the GPU activity within this vma/request, and
* propagate the signal from the request to w->dma.
*/
- err = i915_active_ref(&vma->active, rq->fence.context, rq);
+ err = i915_active_ref(&vma->active, rq->timeline, rq);
if (err)
goto out_request;

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index a6b0cb714292..cd1fd2e5423a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -908,7 +908,7 @@ static int context_barrier_task(struct i915_gem_context *ctx,
if (emit)
err = emit(rq, data);
if (err == 0)
- err = i915_active_ref(&cb->base, rq->fence.context, rq);
+ err = i915_active_ref(&cb->base, rq->timeline, rq);

i915_request_add(rq);
if (err)
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index 9114953bf920..f55691d151ae 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -306,10 +306,10 @@ int intel_context_prepare_remote_request(struct intel_context *ce,

/* Queue this switch after current activity by this context. */
err = i915_active_request_set(&tl->last_request, rq);
+ mutex_unlock(&tl->mutex);
if (err)
- goto unlock;
+ return err;
}
- lockdep_assert_held(&tl->mutex);

/*
* Guarantee context image and the timeline remains pinned until the
@@ -319,12 +319,7 @@ int intel_context_prepare_remote_request(struct intel_context *ce,
* words transfer the pinned ce object to tracked active request.
*/
GEM_BUG_ON(i915_active_is_idle(&ce->active));
- err = i915_active_ref(&ce->active, rq->fence.context, rq);
-
-unlock:
- if (rq->timeline != tl)
- mutex_unlock(&tl->mutex);
- return err;
+ return i915_active_ref(&ce->active, rq->timeline, rq);
}

struct i915_request *intel_context_create_request(struct intel_context *ce)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pool.h b/drivers/gpu/drm/i915/gt/intel_engine_pool.h
index f7a0a660c1c9..8d069efd9457 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pool.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pool.h
@@ -18,7 +18,7 @@ static inline int
intel_engine_pool_mark_active(struct intel_engine_pool_node *node,
struct i915_request *rq)
{
- return i915_active_ref(&node->active, rq->fence.context, rq);
+ return i915_active_ref(&node->active, rq->timeline, rq);
}

static inline void
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c
index eafd94d5e211..02fbe11b671b 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline.c
+++ b/drivers/gpu/drm/i915/gt/intel_timeline.c
@@ -254,7 +254,7 @@ int intel_timeline_init(struct intel_timeline *timeline,

mutex_init(&timeline->mutex);

- INIT_ACTIVE_REQUEST(&timeline->last_request);
+ INIT_ACTIVE_REQUEST(&timeline->last_request, &timeline->mutex);
INIT_LIST_HEAD(&timeline->requests);

i915_syncmap_init(&timeline->sync);
@@ -440,8 +440,7 @@ __intel_timeline_get_seqno(struct intel_timeline *tl,
* free it after the current request is retired, which ensures that
* all writes into the cacheline from previous requests are complete.
*/
- err = i915_active_ref(&tl->hwsp_cacheline->active,
- tl->fence_context, rq);
+ err = i915_active_ref(&tl->hwsp_cacheline->active, tl, rq);
if (err)
goto err_cacheline;

@@ -492,7 +491,7 @@ int intel_timeline_get_seqno(struct intel_timeline *tl,
static int cacheline_ref(struct intel_timeline_cacheline *cl,
struct i915_request *rq)
{
- return i915_active_ref(&cl->active, rq->fence.context, rq);
+ return i915_active_ref(&cl->active, rq->timeline, rq);
}

int intel_timeline_read_hwsp(struct i915_request *from,
diff --git a/drivers/gpu/drm/i915/gt/selftest_timeline.c b/drivers/gpu/drm/i915/gt/selftest_timeline.c
index d54113697745..321481403165 100644
--- a/drivers/gpu/drm/i915/gt/selftest_timeline.c
+++ b/drivers/gpu/drm/i915/gt/selftest_timeline.c
@@ -689,7 +689,9 @@ static int live_hwsp_wrap(void *arg)

tl->seqno = -4u;

+ mutex_lock_nested(&tl->mutex, SINGLE_DEPTH_NESTING);
err = intel_timeline_get_seqno(tl, rq, &seqno[0]);
+ mutex_unlock(&tl->mutex);
if (err) {
i915_request_add(rq);
goto out;
@@ -704,7 +706,9 @@ static int live_hwsp_wrap(void *arg)
}
hwsp_seqno[0] = tl->hwsp_seqno;

+ mutex_lock_nested(&tl->mutex, SINGLE_DEPTH_NESTING);
err = intel_timeline_get_seqno(tl, rq, &seqno[1]);
+ mutex_unlock(&tl->mutex);
if (err) {
i915_request_add(rq);
goto out;
diff --git a/drivers/gpu/drm/i915/gt/selftests/mock_timeline.c b/drivers/gpu/drm/i915/gt/selftests/mock_timeline.c
index 5c549205828a..598170efcaf6 100644
--- a/drivers/gpu/drm/i915/gt/selftests/mock_timeline.c
+++ b/drivers/gpu/drm/i915/gt/selftests/mock_timeline.c
@@ -15,7 +15,7 @@ void mock_timeline_init(struct intel_timeline *timeline, u64 context)

mutex_init(&timeline->mutex);

- INIT_ACTIVE_REQUEST(&timeline->last_request);
+ INIT_ACTIVE_REQUEST(&timeline->last_request, &timeline->mutex);
INIT_LIST_HEAD(&timeline->requests);

i915_syncmap_init(&timeline->sync);
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index 2439c4f62ad8..df6164591702 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -169,10 +169,11 @@ node_retire(struct i915_active_request *base, struct i915_request *rq)
}

static struct i915_active_request *
-active_instance(struct i915_active *ref, u64 idx)
+active_instance(struct i915_active *ref, struct intel_timeline *tl)
{
struct active_node *node, *prealloc;
struct rb_node **p, *parent;
+ u64 idx = tl->fence_context;

/*
* We track the most recently used timeline to skip a rbtree search
@@ -211,7 +212,7 @@ active_instance(struct i915_active *ref, u64 idx)
}

node = prealloc;
- i915_active_request_init(&node->base, NULL, node_retire);
+ i915_active_request_init(&node->base, &tl->mutex, NULL, node_retire);
node->ref = ref;
node->timeline = idx;

@@ -294,18 +295,20 @@ __active_del_barrier(struct i915_active *ref, struct active_node *node)
}

int i915_active_ref(struct i915_active *ref,
- u64 timeline,
+ struct intel_timeline *tl,
struct i915_request *rq)
{
struct i915_active_request *active;
int err;

+ lockdep_assert_held(&tl->mutex);
+
/* Prevent reaping in case we malloc/wait while building the tree */
err = i915_active_acquire(ref);
if (err)
return err;

- active = active_instance(ref, timeline);
+ active = active_instance(ref, tl);
if (!active) {
err = -ENOMEM;
goto out;
@@ -596,6 +599,10 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
goto unwind;
}

+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
+ node->base.lock =
+ &engine->kernel_context->timeline->mutex;
+#endif
RCU_INIT_POINTER(node->base.request, NULL);
node->base.retire = node_retire;
node->timeline = idx;
@@ -701,6 +708,10 @@ int i915_active_request_set(struct i915_active_request *active,
{
int err;

+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
+ lockdep_assert_held(active->lock);
+#endif
+
/* Must maintain ordering wrt previous active requests */
err = i915_request_await_active_request(rq, active);
if (err)
diff --git a/drivers/gpu/drm/i915/i915_active.h b/drivers/gpu/drm/i915/i915_active.h
index f6d730cf2fe6..f95058f99057 100644
--- a/drivers/gpu/drm/i915/i915_active.h
+++ b/drivers/gpu/drm/i915/i915_active.h
@@ -58,15 +58,20 @@ void i915_active_retire_noop(struct i915_active_request *active,
*/
static inline void
i915_active_request_init(struct i915_active_request *active,
+ struct mutex *lock,
struct i915_request *rq,
i915_active_retire_fn retire)
{
RCU_INIT_POINTER(active->request, rq);
INIT_LIST_HEAD(&active->link);
active->retire = retire ?: i915_active_retire_noop;
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
+ active->lock = lock;
+#endif
}

-#define INIT_ACTIVE_REQUEST(name) i915_active_request_init((name), NULL, NULL)
+#define INIT_ACTIVE_REQUEST(name, lock) \
+ i915_active_request_init((name), (lock), NULL, NULL)

/**
* i915_active_request_set - updates the tracker to watch the current request
@@ -81,6 +86,9 @@ static inline void
__i915_active_request_set(struct i915_active_request *active,
struct i915_request *request)
{
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
+ lockdep_assert_held(active->lock);
+#endif
list_move(&active->link, &request->active_list);
rcu_assign_pointer(active->request, request);
}
@@ -362,7 +370,7 @@ void __i915_active_init(struct drm_i915_private *i915,
} while (0)

int i915_active_ref(struct i915_active *ref,
- u64 timeline,
+ struct intel_timeline *tl,
struct i915_request *rq);

int i915_active_wait(struct i915_active *ref);
diff --git a/drivers/gpu/drm/i915/i915_active_types.h b/drivers/gpu/drm/i915/i915_active_types.h
index ae3ee441c114..d857bd12aa7e 100644
--- a/drivers/gpu/drm/i915/i915_active_types.h
+++ b/drivers/gpu/drm/i915/i915_active_types.h
@@ -24,6 +24,9 @@ struct i915_active_request {
struct i915_request __rcu *request;
struct list_head link;
i915_active_retire_fn retire;
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
+ struct mutex *lock;
+#endif
};

struct active_node;
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index a32243951b29..73b02234affe 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -903,14 +903,14 @@ int i915_vma_move_to_active(struct i915_vma *vma,
* add the active reference first and queue for it to be dropped
* *last*.
*/
- err = i915_active_ref(&vma->active, rq->fence.context, rq);
+ err = i915_active_ref(&vma->active, rq->timeline, rq);
if (unlikely(err))
return err;

if (flags & EXEC_OBJECT_WRITE) {
if (intel_frontbuffer_invalidate(obj->frontbuffer, ORIGIN_CS))
i915_active_ref(&obj->frontbuffer->write,
- rq->fence.context,
+ rq->timeline,
rq);

dma_resv_add_excl_fence(vma->resv, &rq->fence);
diff --git a/drivers/gpu/drm/i915/selftests/i915_active.c b/drivers/gpu/drm/i915/selftests/i915_active.c
index e5cd5d47e380..77d844ac8b71 100644
--- a/drivers/gpu/drm/i915/selftests/i915_active.c
+++ b/drivers/gpu/drm/i915/selftests/i915_active.c
@@ -110,8 +110,7 @@ __live_active_setup(struct drm_i915_private *i915)
submit,
GFP_KERNEL);
if (err >= 0)
- err = i915_active_ref(&active->base,
- rq->fence.context, rq);
+ err = i915_active_ref(&active->base, rq->timeline, rq);
i915_request_add(rq);
if (err) {
pr_err("Failed to track active ref!\n");
--
2.23.0.rc1