drm/i915: Pull i915_gem_active into the i915_active family

Looking forward, we need to break the struct_mutex dependency on
i915_gem_active. In the meantime, external use of i915_gem_active is
quite beguiling, little do new users suspect that it implies a barrier
as each request it tracks must be ordered wrt the previous one. As one
of many, it can be used to track activity across multiple timelines, a
shared fence, which fits our unordered request submission much better. We
need to steer external users away from the singular, exclusive fence
imposed by i915_gem_active to i915_active instead. As part of that
process, we move i915_gem_active out of i915_request.c into
i915_active.c to start separating the two concepts, and rename it to
i915_active_request (both to tie it to the concept of tracking just one
request, and to give it a longer, less appealing name).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190205130005.2807-5-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_active.c

@@ -21,7 +21,7 @@ static struct i915_global_active {
 } global;
 
 struct active_node {
-	struct i915_gem_active base;
+	struct i915_active_request base;
 	struct i915_active *ref;
 	struct rb_node node;
 	u64 timeline;
@@ -33,7 +33,7 @@ __active_park(struct i915_active *ref)
 	struct active_node *it, *n;
 
 	rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
-		GEM_BUG_ON(i915_gem_active_isset(&it->base));
+		GEM_BUG_ON(i915_active_request_isset(&it->base));
 		kmem_cache_free(global.slab_cache, it);
 	}
 	ref->tree = RB_ROOT;
@@ -53,18 +53,18 @@ __active_retire(struct i915_active *ref)
 }
 
 static void
-node_retire(struct i915_gem_active *base, struct i915_request *rq)
+node_retire(struct i915_active_request *base, struct i915_request *rq)
 {
 	__active_retire(container_of(base, struct active_node, base)->ref);
 }
 
 static void
-last_retire(struct i915_gem_active *base, struct i915_request *rq)
+last_retire(struct i915_active_request *base, struct i915_request *rq)
 {
 	__active_retire(container_of(base, struct i915_active, last));
 }
 
-static struct i915_gem_active *
+static struct i915_active_request *
 active_instance(struct i915_active *ref, u64 idx)
 {
 	struct active_node *node;
@@ -85,7 +85,7 @@ active_instance(struct i915_active *ref, u64 idx)
 	 * twice for the same timeline (as the older rbtree element will be
 	 * retired before the new request added to last).
 	 */
-	old = i915_gem_active_raw(&ref->last, BKL(ref));
+	old = i915_active_request_raw(&ref->last, BKL(ref));
 	if (!old || old->fence.context == idx)
 		goto out;
 
@@ -110,7 +110,7 @@ active_instance(struct i915_active *ref, u64 idx)
 	node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
 
 	/* kmalloc may retire the ref->last (thanks shrinker)! */
-	if (unlikely(!i915_gem_active_raw(&ref->last, BKL(ref)))) {
+	if (unlikely(!i915_active_request_raw(&ref->last, BKL(ref)))) {
 		kmem_cache_free(global.slab_cache, node);
 		goto out;
 	}
@@ -118,7 +118,7 @@ active_instance(struct i915_active *ref, u64 idx)
 	if (unlikely(!node))
 		return ERR_PTR(-ENOMEM);
 
-	init_request_active(&node->base, node_retire);
+	i915_active_request_init(&node->base, NULL, node_retire);
 	node->ref = ref;
 	node->timeline = idx;
 
@@ -133,7 +133,7 @@ active_instance(struct i915_active *ref, u64 idx)
 	 * callback not two, and so much undo the active counting for the
 	 * overwritten slot.
 	 */
-	if (i915_gem_active_isset(&node->base)) {
+	if (i915_active_request_isset(&node->base)) {
 		/* Retire ourselves from the old rq->active_list */
 		__list_del_entry(&node->base.link);
 		ref->count--;
@@ -154,7 +154,7 @@ void i915_active_init(struct drm_i915_private *i915,
 	ref->i915 = i915;
 	ref->retire = retire;
 	ref->tree = RB_ROOT;
-	init_request_active(&ref->last, last_retire);
+	i915_active_request_init(&ref->last, NULL, last_retire);
 	ref->count = 0;
 }
 
@@ -162,15 +162,15 @@ int i915_active_ref(struct i915_active *ref,
 		    u64 timeline,
 		    struct i915_request *rq)
 {
-	struct i915_gem_active *active;
+	struct i915_active_request *active;
 
 	active = active_instance(ref, timeline);
 	if (IS_ERR(active))
 		return PTR_ERR(active);
 
-	if (!i915_gem_active_isset(active))
+	if (!i915_active_request_isset(active))
 		ref->count++;
-	i915_gem_active_set(active, rq);
+	__i915_active_request_set(active, rq);
 
 	GEM_BUG_ON(!ref->count);
 	return 0;
@@ -196,12 +196,12 @@ int i915_active_wait(struct i915_active *ref)
 	if (i915_active_acquire(ref))
 		goto out_release;
 
-	ret = i915_gem_active_retire(&ref->last, BKL(ref));
+	ret = i915_active_request_retire(&ref->last, BKL(ref));
 	if (ret)
 		goto out_release;
 
 	rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
-		ret = i915_gem_active_retire(&it->base, BKL(ref));
+		ret = i915_active_request_retire(&it->base, BKL(ref));
 		if (ret)
 			break;
 	}
@@ -211,11 +211,11 @@ int i915_active_wait(struct i915_active *ref)
 	return ret;
 }
 
-static int __i915_request_await_active(struct i915_request *rq,
-				       struct i915_gem_active *active)
+int i915_request_await_active_request(struct i915_request *rq,
+				      struct i915_active_request *active)
 {
 	struct i915_request *barrier =
-		i915_gem_active_raw(active, &rq->i915->drm.struct_mutex);
+		i915_active_request_raw(active, &rq->i915->drm.struct_mutex);
 
 	return barrier ? i915_request_await_dma_fence(rq, &barrier->fence) : 0;
 }
@@ -225,12 +225,12 @@ int i915_request_await_active(struct i915_request *rq, struct i915_active *ref)
 	struct active_node *it, *n;
 	int ret;
 
-	ret = __i915_request_await_active(rq, &ref->last);
+	ret = i915_request_await_active_request(rq, &ref->last);
 	if (ret)
 		return ret;
 
 	rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
-		ret = __i915_request_await_active(rq, &it->base);
+		ret = i915_request_await_active_request(rq, &it->base);
 		if (ret)
 			return ret;
 	}
@@ -241,12 +241,32 @@ int i915_request_await_active(struct i915_request *rq, struct i915_active *ref)
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
 void i915_active_fini(struct i915_active *ref)
 {
-	GEM_BUG_ON(i915_gem_active_isset(&ref->last));
+	GEM_BUG_ON(i915_active_request_isset(&ref->last));
 	GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree));
 	GEM_BUG_ON(ref->count);
 }
 #endif
 
+int i915_active_request_set(struct i915_active_request *active,
+			    struct i915_request *rq)
+{
+	int err;
+
+	/* Must maintain ordering wrt previous active requests */
+	err = i915_request_await_active_request(rq, active);
+	if (err)
+		return err;
+
+	__i915_active_request_set(active, rq);
+	return 0;
+}
+
+void i915_active_retire_noop(struct i915_active_request *active,
+			     struct i915_request *request)
+{
+	/* Space left intentionally blank */
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/i915_active.c"
 #endif

drivers/gpu/drm/i915/i915_active.h

@@ -7,7 +7,354 @@
 #ifndef _I915_ACTIVE_H_
 #define _I915_ACTIVE_H_
 
+#include <linux/lockdep.h>
+
 #include "i915_active_types.h"
+#include "i915_request.h"
+
+/*
+ * We treat requests as fences. This is not be to confused with our
+ * "fence registers" but pipeline synchronisation objects ala GL_ARB_sync.
+ * We use the fences to synchronize access from the CPU with activity on the
+ * GPU, for example, we should not rewrite an object's PTE whilst the GPU
+ * is reading them. We also track fences at a higher level to provide
+ * implicit synchronisation around GEM objects, e.g. set-domain will wait
+ * for outstanding GPU rendering before marking the object ready for CPU
+ * access, or a pageflip will wait until the GPU is complete before showing
+ * the frame on the scanout.
+ *
+ * In order to use a fence, the object must track the fence it needs to
+ * serialise with. For example, GEM objects want to track both read and
+ * write access so that we can perform concurrent read operations between
+ * the CPU and GPU engines, as well as waiting for all rendering to
+ * complete, or waiting for the last GPU user of a "fence register". The
+ * object then embeds a #i915_active_request to track the most recent (in
+ * retirement order) request relevant for the desired mode of access.
+ * The #i915_active_request is updated with i915_active_request_set() to
+ * track the most recent fence request, typically this is done as part of
+ * i915_vma_move_to_active().
+ *
+ * When the #i915_active_request completes (is retired), it will
+ * signal its completion to the owner through a callback as well as mark
+ * itself as idle (i915_active_request.request == NULL). The owner
+ * can then perform any action, such as delayed freeing of an active
+ * resource including itself.
+ */
+
+void i915_active_retire_noop(struct i915_active_request *active,
+			     struct i915_request *request);
+
+/**
+ * i915_active_request_init - prepares the activity tracker for use
+ * @active - the active tracker
+ * @rq - initial request to track, can be NULL
+ * @func - a callback when then the tracker is retired (becomes idle),
+ *         can be NULL
+ *
+ * i915_active_request_init() prepares the embedded @active struct for use as
+ * an activity tracker, that is for tracking the last known active request
+ * associated with it. When the last request becomes idle, when it is retired
+ * after completion, the optional callback @func is invoked.
+ */
+static inline void
+i915_active_request_init(struct i915_active_request *active,
+			 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;
+}
+
+#define INIT_ACTIVE_REQUEST(name) i915_active_request_init((name), NULL, NULL)
+
+/**
+ * i915_active_request_set - updates the tracker to watch the current request
+ * @active - the active tracker
+ * @request - the request to watch
+ *
+ * __i915_active_request_set() watches the given @request for completion. Whilst
+ * that @request is busy, the @active reports busy. When that @request is
+ * retired, the @active tracker is updated to report idle.
+ */
+static inline void
+__i915_active_request_set(struct i915_active_request *active,
+			  struct i915_request *request)
+{
+	list_move(&active->link, &request->active_list);
+	rcu_assign_pointer(active->request, request);
+}
+
+int __must_check
+i915_active_request_set(struct i915_active_request *active,
+			struct i915_request *rq);
+
+/**
+ * i915_active_request_set_retire_fn - updates the retirement callback
+ * @active - the active tracker
+ * @fn - the routine called when the request is retired
+ * @mutex - struct_mutex used to guard retirements
+ *
+ * i915_active_request_set_retire_fn() updates the function pointer that
+ * is called when the final request associated with the @active tracker
+ * is retired.
+ */
+static inline void
+i915_active_request_set_retire_fn(struct i915_active_request *active,
+				  i915_active_retire_fn fn,
+				  struct mutex *mutex)
+{
+	lockdep_assert_held(mutex);
+	active->retire = fn ?: i915_active_retire_noop;
+}
+
+static inline struct i915_request *
+__i915_active_request_peek(const struct i915_active_request *active)
+{
+	/*
+	 * Inside the error capture (running with the driver in an unknown
+	 * state), we want to bend the rules slightly (a lot).
+	 *
+	 * Work is in progress to make it safer, in the meantime this keeps
+	 * the known issue from spamming the logs.
+	 */
+	return rcu_dereference_protected(active->request, 1);
+}
+
+/**
+ * i915_active_request_raw - return the active request
+ * @active - the active tracker
+ *
+ * i915_active_request_raw() returns the current request being tracked, or NULL.
+ * It does not obtain a reference on the request for the caller, so the caller
+ * must hold struct_mutex.
+ */
+static inline struct i915_request *
+i915_active_request_raw(const struct i915_active_request *active,
+			struct mutex *mutex)
+{
+	return rcu_dereference_protected(active->request,
+					 lockdep_is_held(mutex));
+}
+
+/**
+ * i915_active_request_peek - report the active request being monitored
+ * @active - the active tracker
+ *
+ * i915_active_request_peek() returns the current request being tracked if
+ * still active, or NULL. It does not obtain a reference on the request
+ * for the caller, so the caller must hold struct_mutex.
+ */
+static inline struct i915_request *
+i915_active_request_peek(const struct i915_active_request *active,
+			 struct mutex *mutex)
+{
+	struct i915_request *request;
+
+	request = i915_active_request_raw(active, mutex);
+	if (!request || i915_request_completed(request))
+		return NULL;
+
+	return request;
+}
+
+/**
+ * i915_active_request_get - return a reference to the active request
+ * @active - the active tracker
+ *
+ * i915_active_request_get() returns a reference to the active request, or NULL
+ * if the active tracker is idle. The caller must hold struct_mutex.
+ */
+static inline struct i915_request *
+i915_active_request_get(const struct i915_active_request *active,
+			struct mutex *mutex)
+{
+	return i915_request_get(i915_active_request_peek(active, mutex));
+}
+
+/**
+ * __i915_active_request_get_rcu - return a reference to the active request
+ * @active - the active tracker
+ *
+ * __i915_active_request_get() returns a reference to the active request,
+ * or NULL if the active tracker is idle. The caller must hold the RCU read
+ * lock, but the returned pointer is safe to use outside of RCU.
+ */
+static inline struct i915_request *
+__i915_active_request_get_rcu(const struct i915_active_request *active)
+{
+	/*
+	 * Performing a lockless retrieval of the active request is super
+	 * tricky. SLAB_TYPESAFE_BY_RCU merely guarantees that the backing
+	 * slab of request objects will not be freed whilst we hold the
+	 * RCU read lock. It does not guarantee that the request itself
+	 * will not be freed and then *reused*. Viz,
+	 *
+	 * Thread A			Thread B
+	 *
+	 * rq = active.request
+	 *				retire(rq) -> free(rq);
+	 *				(rq is now first on the slab freelist)
+	 *				active.request = NULL
+	 *
+	 *				rq = new submission on a new object
+	 * ref(rq)
+	 *
+	 * To prevent the request from being reused whilst the caller
+	 * uses it, we take a reference like normal. Whilst acquiring
+	 * the reference we check that it is not in a destroyed state
+	 * (refcnt == 0). That prevents the request being reallocated
+	 * whilst the caller holds on to it. To check that the request
+	 * was not reallocated as we acquired the reference we have to
+	 * check that our request remains the active request across
+	 * the lookup, in the same manner as a seqlock. The visibility
+	 * of the pointer versus the reference counting is controlled
+	 * by using RCU barriers (rcu_dereference and rcu_assign_pointer).
+	 *
+	 * In the middle of all that, we inspect whether the request is
+	 * complete. Retiring is lazy so the request may be completed long
+	 * before the active tracker is updated. Querying whether the
+	 * request is complete is far cheaper (as it involves no locked
+	 * instructions setting cachelines to exclusive) than acquiring
+	 * the reference, so we do it first. The RCU read lock ensures the
+	 * pointer dereference is valid, but does not ensure that the
+	 * seqno nor HWS is the right one! However, if the request was
+	 * reallocated, that means the active tracker's request was complete.
+	 * If the new request is also complete, then both are and we can
+	 * just report the active tracker is idle. If the new request is
+	 * incomplete, then we acquire a reference on it and check that
+	 * it remained the active request.
+	 *
+	 * It is then imperative that we do not zero the request on
+	 * reallocation, so that we can chase the dangling pointers!
+	 * See i915_request_alloc().
+	 */
+	do {
+		struct i915_request *request;
+
+		request = rcu_dereference(active->request);
+		if (!request || i915_request_completed(request))
+			return NULL;
+
+		/*
+		 * An especially silly compiler could decide to recompute the
+		 * result of i915_request_completed, more specifically
+		 * re-emit the load for request->fence.seqno. A race would catch
+		 * a later seqno value, which could flip the result from true to
+		 * false. Which means part of the instructions below might not
+		 * be executed, while later on instructions are executed. Due to
+		 * barriers within the refcounting the inconsistency can't reach
+		 * past the call to i915_request_get_rcu, but not executing
+		 * that while still executing i915_request_put() creates
+		 * havoc enough.  Prevent this with a compiler barrier.
+		 */
+		barrier();
+
+		request = i915_request_get_rcu(request);
+
+		/*
+		 * What stops the following rcu_access_pointer() from occurring
+		 * before the above i915_request_get_rcu()? If we were
+		 * to read the value before pausing to get the reference to
+		 * the request, we may not notice a change in the active
+		 * tracker.
+		 *
+		 * The rcu_access_pointer() is a mere compiler barrier, which
+		 * means both the CPU and compiler are free to perform the
+		 * memory read without constraint. The compiler only has to
+		 * ensure that any operations after the rcu_access_pointer()
+		 * occur afterwards in program order. This means the read may
+		 * be performed earlier by an out-of-order CPU, or adventurous
+		 * compiler.
+		 *
+		 * The atomic operation at the heart of
+		 * i915_request_get_rcu(), see dma_fence_get_rcu(), is
+		 * atomic_inc_not_zero() which is only a full memory barrier
+		 * when successful. That is, if i915_request_get_rcu()
+		 * returns the request (and so with the reference counted
+		 * incremented) then the following read for rcu_access_pointer()
+		 * must occur after the atomic operation and so confirm
+		 * that this request is the one currently being tracked.
+		 *
+		 * The corresponding write barrier is part of
+		 * rcu_assign_pointer().
+		 */
+		if (!request || request == rcu_access_pointer(active->request))
+			return rcu_pointer_handoff(request);
+
+		i915_request_put(request);
+	} while (1);
+}
+
+/**
+ * i915_active_request_get_unlocked - return a reference to the active request
+ * @active - the active tracker
+ *
+ * i915_active_request_get_unlocked() returns a reference to the active request,
+ * or NULL if the active tracker is idle. The reference is obtained under RCU,
+ * so no locking is required by the caller.
+ *
+ * The reference should be freed with i915_request_put().
+ */
+static inline struct i915_request *
+i915_active_request_get_unlocked(const struct i915_active_request *active)
+{
+	struct i915_request *request;
+
+	rcu_read_lock();
+	request = __i915_active_request_get_rcu(active);
+	rcu_read_unlock();
+
+	return request;
+}
+
+/**
+ * i915_active_request_isset - report whether the active tracker is assigned
+ * @active - the active tracker
+ *
+ * i915_active_request_isset() returns true if the active tracker is currently
+ * assigned to a request. Due to the lazy retiring, that request may be idle
+ * and this may report stale information.
+ */
+static inline bool
+i915_active_request_isset(const struct i915_active_request *active)
+{
+	return rcu_access_pointer(active->request);
+}
+
+/**
+ * i915_active_request_retire - waits until the request is retired
+ * @active - the active request on which to wait
+ *
+ * i915_active_request_retire() waits until the request is completed,
+ * and then ensures that at least the retirement handler for this
+ * @active tracker is called before returning. If the @active
+ * tracker is idle, the function returns immediately.
+ */
+static inline int __must_check
+i915_active_request_retire(struct i915_active_request *active,
+			   struct mutex *mutex)
+{
+	struct i915_request *request;
+	long ret;
+
+	request = i915_active_request_raw(active, mutex);
+	if (!request)
+		return 0;
+
+	ret = i915_request_wait(request,
+				I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
+				MAX_SCHEDULE_TIMEOUT);
+	if (ret < 0)
+		return ret;
+
+	list_del_init(&active->link);
+	RCU_INIT_POINTER(active->request, NULL);
+
+	active->retire(active, request);
+
+	return 0;
+}
 
 /*
  * GPU activity tracking
@@ -47,6 +394,8 @@ int i915_active_wait(struct i915_active *ref);
 
 int i915_request_await_active(struct i915_request *rq,
 			      struct i915_active *ref);
+int i915_request_await_active_request(struct i915_request *rq,
+				      struct i915_active_request *active);
 
 bool i915_active_acquire(struct i915_active *ref);
 

drivers/gpu/drm/i915/i915_active_types.h

@@ -8,16 +8,26 @@
 #define _I915_ACTIVE_TYPES_H_
 
 #include <linux/rbtree.h>
-
-#include "i915_request.h"
+#include <linux/rcupdate.h>
 
 struct drm_i915_private;
+struct i915_active_request;
+struct i915_request;
+
+typedef void (*i915_active_retire_fn)(struct i915_active_request *,
+				      struct i915_request *);
+
+struct i915_active_request {
+	struct i915_request __rcu *request;
+	struct list_head link;
+	i915_active_retire_fn retire;
+};
 
 struct i915_active {
 	struct drm_i915_private *i915;
 
 	struct rb_root tree;
-	struct i915_gem_active last;
+	struct i915_active_request last;
 	unsigned int count;
 
 	void (*retire)(struct i915_active *ref);

drivers/gpu/drm/i915/i915_debugfs.c

@@ -206,7 +206,7 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 		if (vma->fence)
 			seq_printf(m, " , fence: %d%s",
 				   vma->fence->id,
-				   i915_gem_active_isset(&vma->last_fence) ? "*" : "");
+				   i915_active_request_isset(&vma->last_fence) ? "*" : "");
 		seq_puts(m, ")");
 	}
 	if (obj->stolen)

drivers/gpu/drm/i915/i915_gem.c

@@ -3018,7 +3018,7 @@ static void assert_kernel_context_is_current(struct drm_i915_private *i915)
 
 	GEM_BUG_ON(i915->gt.active_requests);
 	for_each_engine(engine, i915, id) {
-		GEM_BUG_ON(__i915_gem_active_peek(&engine->timeline.last_request));
+		GEM_BUG_ON(__i915_active_request_peek(&engine->timeline.last_request));
 		GEM_BUG_ON(engine->last_retired_context !=
 			   to_intel_context(i915->kernel_context, engine));
 	}
@@ -3264,7 +3264,7 @@ wait_for_timelines(struct drm_i915_private *i915,
 	list_for_each_entry(tl, &gt->active_list, link) {
 		struct i915_request *rq;
 
-		rq = i915_gem_active_get_unlocked(&tl->last_request);
+		rq = i915_active_request_get_unlocked(&tl->last_request);
 		if (!rq)
 			continue;
 
@@ -4165,7 +4165,8 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 }
 
 static void
-frontbuffer_retire(struct i915_gem_active *active, struct i915_request *request)
+frontbuffer_retire(struct i915_active_request *active,
+		   struct i915_request *request)
 {
 	struct drm_i915_gem_object *obj =
 		container_of(active, typeof(*obj), frontbuffer_write);
@@ -4192,7 +4193,8 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
 	obj->resv = &obj->__builtin_resv;
 
 	obj->frontbuffer_ggtt_origin = ORIGIN_GTT;
-	init_request_active(&obj->frontbuffer_write, frontbuffer_retire);
+	i915_active_request_init(&obj->frontbuffer_write,
+				 NULL, frontbuffer_retire);
 
 	obj->mm.madv = I915_MADV_WILLNEED;
 	INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN);

drivers/gpu/drm/i915/i915_gem_context.c

@@ -322,7 +322,7 @@ static u32 default_desc_template(const struct drm_i915_private *i915,
 	return desc;
 }
 
-static void intel_context_retire(struct i915_gem_active *active,
+static void intel_context_retire(struct i915_active_request *active,
 				 struct i915_request *rq)
 {
 	struct intel_context *ce =
@@ -344,7 +344,8 @@ intel_context_init(struct intel_context *ce,
 	/* Use the whole device by default */
 	ce->sseu = intel_device_default_sseu(ctx->i915);
 
-	init_request_active(&ce->active_tracker, intel_context_retire);
+	i915_active_request_init(&ce->active_tracker,
+				 NULL, intel_context_retire);
 }
 
 static struct i915_gem_context *
@@ -668,8 +669,8 @@ last_request_on_engine(struct i915_timeline *timeline,
 
 	GEM_BUG_ON(timeline == &engine->timeline);
 
-	rq = i915_gem_active_raw(&timeline->last_request,
-				 &engine->i915->drm.struct_mutex);
+	rq = i915_active_request_raw(&timeline->last_request,
+				     &engine->i915->drm.struct_mutex);
 	if (rq && rq->engine == engine) {
 		GEM_TRACE("last request for %s on engine %s: %llx:%llu\n",
 			  timeline->name, engine->name,
@@ -1015,8 +1016,8 @@ gen8_modify_rpcs_gpu(struct intel_context *ce,
 	}
 
 	/* Queue this switch after all other activity by this context. */
-	prev = i915_gem_active_raw(&ce->ring->timeline->last_request,
-				   &i915->drm.struct_mutex);
+	prev = i915_active_request_raw(&ce->ring->timeline->last_request,
+				       &i915->drm.struct_mutex);
 	if (prev && !i915_request_completed(prev)) {
 		ret = i915_request_await_dma_fence(rq, &prev->fence);
 		if (ret < 0)
@@ -1039,9 +1040,9 @@ gen8_modify_rpcs_gpu(struct intel_context *ce,
 	 * But we only need to take one pin on the account of it. Or in other
 	 * words transfer the pinned ce object to tracked active request.
 	 */
-	if (!i915_gem_active_isset(&ce->active_tracker))
+	if (!i915_active_request_isset(&ce->active_tracker))
 		__intel_context_pin(ce);
-	i915_gem_active_set(&ce->active_tracker, rq);
+	__i915_active_request_set(&ce->active_tracker, rq);
 
 out_add:
 	i915_request_add(rq);

drivers/gpu/drm/i915/i915_gem_context.h

@@ -187,7 +187,7 @@ struct i915_gem_context {
 		 * active_tracker: Active tracker for the external rq activity
 		 * on this intel_context object.
 		 */
-		struct i915_gem_active active_tracker;
+		struct i915_active_request active_tracker;
 
 		const struct intel_context_ops *ops;
 

drivers/gpu/drm/i915/i915_gem_fence_reg.c

@@ -223,7 +223,7 @@ static int fence_update(struct drm_i915_fence_reg *fence,
 			 i915_gem_object_get_tiling(vma->obj)))
 			return -EINVAL;
 
-		ret = i915_gem_active_retire(&vma->last_fence,
+		ret = i915_active_request_retire(&vma->last_fence,
 					     &vma->obj->base.dev->struct_mutex);
 		if (ret)
 			return ret;
@@ -232,7 +232,7 @@ static int fence_update(struct drm_i915_fence_reg *fence,
 	if (fence->vma) {
 		struct i915_vma *old = fence->vma;
 
-		ret = i915_gem_active_retire(&old->last_fence,
+		ret = i915_active_request_retire(&old->last_fence,
 					     &old->obj->base.dev->struct_mutex);
 		if (ret)
 			return ret;

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -1918,7 +1918,7 @@ static struct i915_vma *pd_vma_create(struct gen6_hw_ppgtt *ppgtt, int size)
 		return ERR_PTR(-ENOMEM);
 
 	i915_active_init(i915, &vma->active, NULL);
-	init_request_active(&vma->last_fence, NULL);
+	INIT_ACTIVE_REQUEST(&vma->last_fence);
 
 	vma->vm = &ggtt->vm;
 	vma->ops = &pd_vma_ops;

drivers/gpu/drm/i915/i915_gem_object.h

@@ -175,7 +175,7 @@ struct drm_i915_gem_object {
 
 	atomic_t frontbuffer_bits;
 	unsigned int frontbuffer_ggtt_origin; /* write once */
-	struct i915_gem_active frontbuffer_write;
+	struct i915_active_request frontbuffer_write;
 
 	/** Current tiling stride for the object, if it's tiled. */
 	unsigned int tiling_and_stride;

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -1062,23 +1062,23 @@ i915_error_object_create(struct drm_i915_private *i915,
 }
 
 /* The error capture is special as tries to run underneath the normal
- * locking rules - so we use the raw version of the i915_gem_active lookup.
+ * locking rules - so we use the raw version of the i915_active_request lookup.
  */
 static inline u32
-__active_get_seqno(struct i915_gem_active *active)
+__active_get_seqno(struct i915_active_request *active)
 {
 	struct i915_request *request;
 
-	request = __i915_gem_active_peek(active);
+	request = __i915_active_request_peek(active);
 	return request ? request->global_seqno : 0;
 }
 
 static inline int
-__active_get_engine_id(struct i915_gem_active *active)
+__active_get_engine_id(struct i915_active_request *active)
 {
 	struct i915_request *request;
 
-	request = __i915_gem_active_peek(active);
+	request = __i915_active_request_peek(active);
 	return request ? request->engine->id : -1;
 }
 

drivers/gpu/drm/i915/i915_request.c

@@ -29,6 +29,7 @@
 #include <linux/sched/signal.h>
 
 #include "i915_drv.h"
+#include "i915_active.h"
 #include "i915_reset.h"
 
 static const char *i915_fence_get_driver_name(struct dma_fence *fence)
@@ -125,12 +126,6 @@ static void unreserve_gt(struct drm_i915_private *i915)
 		i915_gem_park(i915);
 }
 
-void i915_gem_retire_noop(struct i915_gem_active *active,
-			  struct i915_request *request)
-{
-	/* Space left intentionally blank */
-}
-
 static void advance_ring(struct i915_request *request)
 {
 	struct intel_ring *ring = request->ring;
@@ -244,7 +239,7 @@ static void __retire_engine_upto(struct intel_engine_cs *engine,
 
 static void i915_request_retire(struct i915_request *request)
 {
-	struct i915_gem_active *active, *next;
+	struct i915_active_request *active, *next;
 
 	GEM_TRACE("%s fence %llx:%lld, global=%d, current %d:%d\n",
 		  request->engine->name,
@@ -278,10 +273,10 @@ static void i915_request_retire(struct i915_request *request)
 		 * we may spend an inordinate amount of time simply handling
 		 * the retirement of requests and processing their callbacks.
 		 * Of which, this loop itself is particularly hot due to the
-		 * cache misses when jumping around the list of i915_gem_active.
-		 * So we try to keep this loop as streamlined as possible and
-		 * also prefetch the next i915_gem_active to try and hide
-		 * the likely cache miss.
+		 * cache misses when jumping around the list of
+		 * i915_active_request.  So we try to keep this loop as
+		 * streamlined as possible and also prefetch the next
+		 * i915_active_request to try and hide the likely cache miss.
 		 */
 		prefetchw(next);
 
@@ -526,17 +521,9 @@ i915_request_alloc_slow(struct intel_context *ce)
 	return kmem_cache_alloc(ce->gem_context->i915->requests, GFP_KERNEL);
 }
 
-static int add_barrier(struct i915_request *rq, struct i915_gem_active *active)
-{
-	struct i915_request *barrier =
-		i915_gem_active_raw(active, &rq->i915->drm.struct_mutex);
-
-	return barrier ? i915_request_await_dma_fence(rq, &barrier->fence) : 0;
-}
-
 static int add_timeline_barrier(struct i915_request *rq)
 {
-	return add_barrier(rq, &rq->timeline->barrier);
+	return i915_request_await_active_request(rq, &rq->timeline->barrier);
 }
 
 /**
@@ -595,7 +582,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
 	 * We use RCU to look up requests in flight. The lookups may
 	 * race with the request being allocated from the slab freelist.
 	 * That is the request we are writing to here, may be in the process
-	 * of being read by __i915_gem_active_get_rcu(). As such,
+	 * of being read by __i915_active_request_get_rcu(). As such,
 	 * we have to be very careful when overwriting the contents. During
 	 * the RCU lookup, we change chase the request->engine pointer,
 	 * read the request->global_seqno and increment the reference count.
@@ -937,8 +924,8 @@ void i915_request_add(struct i915_request *request)
 	 * see a more recent value in the hws than we are tracking.
 	 */
 
-	prev = i915_gem_active_raw(&timeline->last_request,
-				   &request->i915->drm.struct_mutex);
+	prev = i915_active_request_raw(&timeline->last_request,
+				       &request->i915->drm.struct_mutex);
 	if (prev && !i915_request_completed(prev)) {
 		i915_sw_fence_await_sw_fence(&request->submit, &prev->submit,
 					     &request->submitq);
@@ -954,7 +941,7 @@ void i915_request_add(struct i915_request *request)
 	spin_unlock_irq(&timeline->lock);
 
 	GEM_BUG_ON(timeline->seqno != request->fence.seqno);
-	i915_gem_active_set(&timeline->last_request, request);
+	__i915_active_request_set(&timeline->last_request, request);
 
 	list_add_tail(&request->ring_link, &ring->request_list);
 	if (list_is_first(&request->ring_link, &ring->request_list)) {

drivers/gpu/drm/i915/i915_request.h

@@ -403,387 +403,4 @@ static inline void i915_request_mark_complete(struct i915_request *rq)
 
 void i915_retire_requests(struct drm_i915_private *i915);
 
-/*
- * We treat requests as fences. This is not be to confused with our
- * "fence registers" but pipeline synchronisation objects ala GL_ARB_sync.
- * We use the fences to synchronize access from the CPU with activity on the
- * GPU, for example, we should not rewrite an object's PTE whilst the GPU
- * is reading them. We also track fences at a higher level to provide
- * implicit synchronisation around GEM objects, e.g. set-domain will wait
- * for outstanding GPU rendering before marking the object ready for CPU
- * access, or a pageflip will wait until the GPU is complete before showing
- * the frame on the scanout.
- *
- * In order to use a fence, the object must track the fence it needs to
- * serialise with. For example, GEM objects want to track both read and
- * write access so that we can perform concurrent read operations between
- * the CPU and GPU engines, as well as waiting for all rendering to
- * complete, or waiting for the last GPU user of a "fence register". The
- * object then embeds a #i915_gem_active to track the most recent (in
- * retirement order) request relevant for the desired mode of access.
- * The #i915_gem_active is updated with i915_gem_active_set() to track the
- * most recent fence request, typically this is done as part of
- * i915_vma_move_to_active().
- *
- * When the #i915_gem_active completes (is retired), it will
- * signal its completion to the owner through a callback as well as mark
- * itself as idle (i915_gem_active.request == NULL). The owner
- * can then perform any action, such as delayed freeing of an active
- * resource including itself.
- */
-struct i915_gem_active;
-
-typedef void (*i915_gem_retire_fn)(struct i915_gem_active *,
-				   struct i915_request *);
-
-struct i915_gem_active {
-	struct i915_request __rcu *request;
-	struct list_head link;
-	i915_gem_retire_fn retire;
-};
-
-void i915_gem_retire_noop(struct i915_gem_active *,
-			  struct i915_request *request);
-
-/**
- * init_request_active - prepares the activity tracker for use
- * @active - the active tracker
- * @func - a callback when then the tracker is retired (becomes idle),
- *         can be NULL
- *
- * init_request_active() prepares the embedded @active struct for use as
- * an activity tracker, that is for tracking the last known active request
- * associated with it. When the last request becomes idle, when it is retired
- * after completion, the optional callback @func is invoked.
- */
-static inline void
-init_request_active(struct i915_gem_active *active,
-		    i915_gem_retire_fn retire)
-{
-	RCU_INIT_POINTER(active->request, NULL);
-	INIT_LIST_HEAD(&active->link);
-	active->retire = retire ?: i915_gem_retire_noop;
-}
-
-/**
- * i915_gem_active_set - updates the tracker to watch the current request
- * @active - the active tracker
- * @request - the request to watch
- *
- * i915_gem_active_set() watches the given @request for completion. Whilst
- * that @request is busy, the @active reports busy. When that @request is
- * retired, the @active tracker is updated to report idle.
- */
-static inline void
-i915_gem_active_set(struct i915_gem_active *active,
-		    struct i915_request *request)
-{
-	list_move(&active->link, &request->active_list);
-	rcu_assign_pointer(active->request, request);
-}
-
-/**
- * i915_gem_active_set_retire_fn - updates the retirement callback
- * @active - the active tracker
- * @fn - the routine called when the request is retired
- * @mutex - struct_mutex used to guard retirements
- *
- * i915_gem_active_set_retire_fn() updates the function pointer that
- * is called when the final request associated with the @active tracker
- * is retired.
- */
-static inline void
-i915_gem_active_set_retire_fn(struct i915_gem_active *active,
-			      i915_gem_retire_fn fn,
-			      struct mutex *mutex)
-{
-	lockdep_assert_held(mutex);
-	active->retire = fn ?: i915_gem_retire_noop;
-}
-
-static inline struct i915_request *
-__i915_gem_active_peek(const struct i915_gem_active *active)
-{
-	/*
-	 * Inside the error capture (running with the driver in an unknown
-	 * state), we want to bend the rules slightly (a lot).
-	 *
-	 * Work is in progress to make it safer, in the meantime this keeps
-	 * the known issue from spamming the logs.
-	 */
-	return rcu_dereference_protected(active->request, 1);
-}
-
-/**
- * i915_gem_active_raw - return the active request
- * @active - the active tracker
- *
- * i915_gem_active_raw() returns the current request being tracked, or NULL.
- * It does not obtain a reference on the request for the caller, so the caller
- * must hold struct_mutex.
- */
-static inline struct i915_request *
-i915_gem_active_raw(const struct i915_gem_active *active, struct mutex *mutex)
-{
-	return rcu_dereference_protected(active->request,
-					 lockdep_is_held(mutex));
-}
-
-/**
- * i915_gem_active_peek - report the active request being monitored
- * @active - the active tracker
- *
- * i915_gem_active_peek() returns the current request being tracked if
- * still active, or NULL. It does not obtain a reference on the request
- * for the caller, so the caller must hold struct_mutex.
- */
-static inline struct i915_request *
-i915_gem_active_peek(const struct i915_gem_active *active, struct mutex *mutex)
-{
-	struct i915_request *request;
-
-	request = i915_gem_active_raw(active, mutex);
-	if (!request || i915_request_completed(request))
-		return NULL;
-
-	return request;
-}
-
-/**
- * i915_gem_active_get - return a reference to the active request
- * @active - the active tracker
- *
- * i915_gem_active_get() returns a reference to the active request, or NULL
- * if the active tracker is idle. The caller must hold struct_mutex.
- */
-static inline struct i915_request *
-i915_gem_active_get(const struct i915_gem_active *active, struct mutex *mutex)
-{
-	return i915_request_get(i915_gem_active_peek(active, mutex));
-}
-
-/**
- * __i915_gem_active_get_rcu - return a reference to the active request
- * @active - the active tracker
- *
- * __i915_gem_active_get() returns a reference to the active request, or NULL
- * if the active tracker is idle. The caller must hold the RCU read lock, but
- * the returned pointer is safe to use outside of RCU.
- */
-static inline struct i915_request *
-__i915_gem_active_get_rcu(const struct i915_gem_active *active)
-{
-	/*
-	 * Performing a lockless retrieval of the active request is super
-	 * tricky. SLAB_TYPESAFE_BY_RCU merely guarantees that the backing
-	 * slab of request objects will not be freed whilst we hold the
-	 * RCU read lock. It does not guarantee that the request itself
-	 * will not be freed and then *reused*. Viz,
-	 *
-	 * Thread A			Thread B
-	 *
-	 * rq = active.request
-	 *				retire(rq) -> free(rq);
-	 *				(rq is now first on the slab freelist)
-	 *				active.request = NULL
-	 *
-	 *				rq = new submission on a new object
-	 * ref(rq)
-	 *
-	 * To prevent the request from being reused whilst the caller
-	 * uses it, we take a reference like normal. Whilst acquiring
-	 * the reference we check that it is not in a destroyed state
-	 * (refcnt == 0). That prevents the request being reallocated
-	 * whilst the caller holds on to it. To check that the request
-	 * was not reallocated as we acquired the reference we have to
-	 * check that our request remains the active request across
-	 * the lookup, in the same manner as a seqlock. The visibility
-	 * of the pointer versus the reference counting is controlled
-	 * by using RCU barriers (rcu_dereference and rcu_assign_pointer).
-	 *
-	 * In the middle of all that, we inspect whether the request is
-	 * complete. Retiring is lazy so the request may be completed long
-	 * before the active tracker is updated. Querying whether the
-	 * request is complete is far cheaper (as it involves no locked
-	 * instructions setting cachelines to exclusive) than acquiring
-	 * the reference, so we do it first. The RCU read lock ensures the
-	 * pointer dereference is valid, but does not ensure that the
-	 * seqno nor HWS is the right one! However, if the request was
-	 * reallocated, that means the active tracker's request was complete.
-	 * If the new request is also complete, then both are and we can
-	 * just report the active tracker is idle. If the new request is
-	 * incomplete, then we acquire a reference on it and check that
-	 * it remained the active request.
-	 *
-	 * It is then imperative that we do not zero the request on
-	 * reallocation, so that we can chase the dangling pointers!
-	 * See i915_request_alloc().
-	 */
-	do {
-		struct i915_request *request;
-
-		request = rcu_dereference(active->request);
-		if (!request || i915_request_completed(request))
-			return NULL;
-
-		/*
-		 * An especially silly compiler could decide to recompute the
-		 * result of i915_request_completed, more specifically
-		 * re-emit the load for request->fence.seqno. A race would catch
-		 * a later seqno value, which could flip the result from true to
-		 * false. Which means part of the instructions below might not
-		 * be executed, while later on instructions are executed. Due to
-		 * barriers within the refcounting the inconsistency can't reach
-		 * past the call to i915_request_get_rcu, but not executing
-		 * that while still executing i915_request_put() creates
-		 * havoc enough.  Prevent this with a compiler barrier.
-		 */
-		barrier();
-
-		request = i915_request_get_rcu(request);
-
-		/*
-		 * What stops the following rcu_access_pointer() from occurring
-		 * before the above i915_request_get_rcu()? If we were
-		 * to read the value before pausing to get the reference to
-		 * the request, we may not notice a change in the active
-		 * tracker.
-		 *
-		 * The rcu_access_pointer() is a mere compiler barrier, which
-		 * means both the CPU and compiler are free to perform the
-		 * memory read without constraint. The compiler only has to
-		 * ensure that any operations after the rcu_access_pointer()
-		 * occur afterwards in program order. This means the read may
-		 * be performed earlier by an out-of-order CPU, or adventurous
-		 * compiler.
-		 *
-		 * The atomic operation at the heart of
-		 * i915_request_get_rcu(), see dma_fence_get_rcu(), is
-		 * atomic_inc_not_zero() which is only a full memory barrier
-		 * when successful. That is, if i915_request_get_rcu()
-		 * returns the request (and so with the reference counted
-		 * incremented) then the following read for rcu_access_pointer()
-		 * must occur after the atomic operation and so confirm
-		 * that this request is the one currently being tracked.
-		 *
-		 * The corresponding write barrier is part of
-		 * rcu_assign_pointer().
-		 */
-		if (!request || request == rcu_access_pointer(active->request))
-			return rcu_pointer_handoff(request);
-
-		i915_request_put(request);
-	} while (1);
-}
-
-/**
- * i915_gem_active_get_unlocked - return a reference to the active request
- * @active - the active tracker
- *
- * i915_gem_active_get_unlocked() returns a reference to the active request,
- * or NULL if the active tracker is idle. The reference is obtained under RCU,
- * so no locking is required by the caller.
- *
- * The reference should be freed with i915_request_put().
- */
-static inline struct i915_request *
-i915_gem_active_get_unlocked(const struct i915_gem_active *active)
-{
-	struct i915_request *request;
-
-	rcu_read_lock();
-	request = __i915_gem_active_get_rcu(active);
-	rcu_read_unlock();
-
-	return request;
-}
-
-/**
- * i915_gem_active_isset - report whether the active tracker is assigned
- * @active - the active tracker
- *
- * i915_gem_active_isset() returns true if the active tracker is currently
- * assigned to a request. Due to the lazy retiring, that request may be idle
- * and this may report stale information.
- */
-static inline bool
-i915_gem_active_isset(const struct i915_gem_active *active)
-{
-	return rcu_access_pointer(active->request);
-}
-
-/**
- * i915_gem_active_wait - waits until the request is completed
- * @active - the active request on which to wait
- * @flags - how to wait
- * @timeout - how long to wait at most
- * @rps - userspace client to charge for a waitboost
- *
- * i915_gem_active_wait() waits until the request is completed before
- * returning, without requiring any locks to be held. Note that it does not
- * retire any requests before returning.
- *
- * This function relies on RCU in order to acquire the reference to the active
- * request without holding any locks. See __i915_gem_active_get_rcu() for the
- * glory details on how that is managed. Once the reference is acquired, we
- * can then wait upon the request, and afterwards release our reference,
- * free of any locking.
- *
- * This function wraps i915_request_wait(), see it for the full details on
- * the arguments.
- *
- * Returns 0 if successful, or a negative error code.
- */
-static inline int
-i915_gem_active_wait(const struct i915_gem_active *active, unsigned int flags)
-{
-	struct i915_request *request;
-	long ret = 0;
-
-	request = i915_gem_active_get_unlocked(active);
-	if (request) {
-		ret = i915_request_wait(request, flags, MAX_SCHEDULE_TIMEOUT);
-		i915_request_put(request);
-	}
-
-	return ret < 0 ? ret : 0;
-}
-
-/**
- * i915_gem_active_retire - waits until the request is retired
- * @active - the active request on which to wait
- *
- * i915_gem_active_retire() waits until the request is completed,
- * and then ensures that at least the retirement handler for this
- * @active tracker is called before returning. If the @active
- * tracker is idle, the function returns immediately.
- */
-static inline int __must_check
-i915_gem_active_retire(struct i915_gem_active *active,
-		       struct mutex *mutex)
-{
-	struct i915_request *request;
-	long ret;
-
-	request = i915_gem_active_raw(active, mutex);
-	if (!request)
-		return 0;
-
-	ret = i915_request_wait(request,
-				I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
-				MAX_SCHEDULE_TIMEOUT);
-	if (ret < 0)
-		return ret;
-
-	list_del_init(&active->link);
-	RCU_INIT_POINTER(active->request, NULL);
-
-	active->retire(active, request);
-
-	return 0;
-}
-
-#define for_each_active(mask, idx) \
-	for (; mask ? idx = ffs(mask) - 1, 1 : 0; mask &= ~BIT(idx))
-
 #endif /* I915_REQUEST_H */

drivers/gpu/drm/i915/i915_reset.c

@@ -862,7 +862,7 @@ bool i915_gem_unset_wedged(struct drm_i915_private *i915)
 		struct i915_request *rq;
 		long timeout;
 
-		rq = i915_gem_active_get_unlocked(&tl->last_request);
+		rq = i915_active_request_get_unlocked(&tl->last_request);
 		if (!rq)
 			continue;
 

drivers/gpu/drm/i915/i915_timeline.c

@@ -163,8 +163,8 @@ int i915_timeline_init(struct drm_i915_private *i915,
 
 	spin_lock_init(&timeline->lock);
 
-	init_request_active(&timeline->barrier, NULL);
-	init_request_active(&timeline->last_request, NULL);
+	INIT_ACTIVE_REQUEST(&timeline->barrier);
+	INIT_ACTIVE_REQUEST(&timeline->last_request);
 	INIT_LIST_HEAD(&timeline->requests);
 
 	i915_syncmap_init(&timeline->sync);
@@ -236,7 +236,7 @@ void i915_timeline_fini(struct i915_timeline *timeline)
 {
 	GEM_BUG_ON(timeline->pin_count);
 	GEM_BUG_ON(!list_empty(&timeline->requests));
-	GEM_BUG_ON(i915_gem_active_isset(&timeline->barrier));
+	GEM_BUG_ON(i915_active_request_isset(&timeline->barrier));
 
 	i915_syncmap_free(&timeline->sync);
 	hwsp_free(timeline);
@@ -311,25 +311,6 @@ void i915_timeline_unpin(struct i915_timeline *tl)
 	__i915_vma_unpin(tl->hwsp_ggtt);
 }
 
-int i915_timeline_set_barrier(struct i915_timeline *tl, struct i915_request *rq)
-{
-	struct i915_request *old;
-	int err;
-
-	lockdep_assert_held(&rq->i915->drm.struct_mutex);
-
-	/* Must maintain ordering wrt existing barriers */
-	old = i915_gem_active_raw(&tl->barrier, &rq->i915->drm.struct_mutex);
-	if (old) {
-		err = i915_request_await_dma_fence(rq, &old->fence);
-		if (err)
-			return err;
-	}
-
-	i915_gem_active_set(&tl->barrier, rq);
-	return 0;
-}
-
 void __i915_timeline_free(struct kref *kref)
 {
 	struct i915_timeline *timeline =

drivers/gpu/drm/i915/i915_timeline.h

@@ -28,6 +28,7 @@
 #include <linux/list.h>
 #include <linux/kref.h>
 
+#include "i915_active.h"
 #include "i915_request.h"
 #include "i915_syncmap.h"
 #include "i915_utils.h"
@@ -58,10 +59,10 @@ struct i915_timeline {
 
 	/* Contains an RCU guarded pointer to the last request. No reference is
 	 * held to the request, users must carefully acquire a reference to
-	 * the request using i915_gem_active_get_request_rcu(), or hold the
+	 * the request using i915_active_request_get_request_rcu(), or hold the
 	 * struct_mutex.
 	 */
-	struct i915_gem_active last_request;
+	struct i915_active_request last_request;
 
 	/**
 	 * We track the most recent seqno that we wait on in every context so
@@ -82,7 +83,7 @@ struct i915_timeline {
 	 * subsequent submissions to this timeline be executed only after the
 	 * barrier has been completed.
 	 */
-	struct i915_gem_active barrier;
+	struct i915_active_request barrier;
 
 	struct list_head link;
 	const char *name;
@@ -174,7 +175,10 @@ void i915_timelines_fini(struct drm_i915_private *i915);
  * submissions on @timeline. Subsequent requests will not be submitted to GPU
  * until the barrier has been completed.
  */
-int i915_timeline_set_barrier(struct i915_timeline *timeline,
-			      struct i915_request *rq);
+static inline int
+i915_timeline_set_barrier(struct i915_timeline *tl, struct i915_request *rq)
+{
+	return i915_active_request_set(&tl->barrier, rq);
+}
 
 #endif

drivers/gpu/drm/i915/i915_vma.c

@@ -120,7 +120,7 @@ vma_create(struct drm_i915_gem_object *obj,
 		return ERR_PTR(-ENOMEM);
 
 	i915_active_init(vm->i915, &vma->active, __i915_vma_retire);
-	init_request_active(&vma->last_fence, NULL);
+	INIT_ACTIVE_REQUEST(&vma->last_fence);
 
 	vma->vm = vm;
 	vma->ops = &vm->vma_ops;
@@ -808,7 +808,7 @@ static void __i915_vma_destroy(struct i915_vma *vma)
 	GEM_BUG_ON(vma->node.allocated);
 	GEM_BUG_ON(vma->fence);
 
-	GEM_BUG_ON(i915_gem_active_isset(&vma->last_fence));
+	GEM_BUG_ON(i915_active_request_isset(&vma->last_fence));
 
 	mutex_lock(&vma->vm->mutex);
 	list_del(&vma->vm_link);
@@ -942,14 +942,14 @@ int i915_vma_move_to_active(struct i915_vma *vma,
 		obj->write_domain = I915_GEM_DOMAIN_RENDER;
 
 		if (intel_fb_obj_invalidate(obj, ORIGIN_CS))
-			i915_gem_active_set(&obj->frontbuffer_write, rq);
+			__i915_active_request_set(&obj->frontbuffer_write, rq);
 
 		obj->read_domains = 0;
 	}
 	obj->read_domains |= I915_GEM_GPU_DOMAINS;
 
 	if (flags & EXEC_OBJECT_NEEDS_FENCE)
-		i915_gem_active_set(&vma->last_fence, rq);
+		__i915_active_request_set(&vma->last_fence, rq);
 
 	export_fence(vma, rq, flags);
 	return 0;
@@ -986,8 +986,8 @@ int i915_vma_unbind(struct i915_vma *vma)
 		if (ret)
 			goto unpin;
 
-		ret = i915_gem_active_retire(&vma->last_fence,
-					     &vma->vm->i915->drm.struct_mutex);
+		ret = i915_active_request_retire(&vma->last_fence,
+					      &vma->vm->i915->drm.struct_mutex);
 unpin:
 		__i915_vma_unpin(vma);
 		if (ret)

drivers/gpu/drm/i915/i915_vma.h

@@ -110,7 +110,7 @@ struct i915_vma {
 #define I915_VMA_GGTT_WRITE	BIT(15)
 
 	struct i915_active active;
-	struct i915_gem_active last_fence;
+	struct i915_active_request last_fence;
 
 	/**
 	 * Support different GGTT views into the same object.

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -1086,7 +1086,7 @@ bool intel_engine_has_kernel_context(const struct intel_engine_cs *engine)
 	 * the last request that remains in the timeline. When idle, it is
 	 * the last executed context as tracked by retirement.
 	 */
-	rq = __i915_gem_active_peek(&engine->timeline.last_request);
+	rq = __i915_active_request_peek(&engine->timeline.last_request);
 	if (rq)
 		return rq->hw_context == kernel_context;
 	else

drivers/gpu/drm/i915/intel_overlay.c

@@ -184,7 +184,7 @@ struct intel_overlay {
 	struct overlay_registers __iomem *regs;
 	u32 flip_addr;
 	/* flip handling */
-	struct i915_gem_active last_flip;
+	struct i915_active_request last_flip;
 };
 
 static void i830_overlay_clock_gating(struct drm_i915_private *dev_priv,
@@ -212,23 +212,23 @@ static void i830_overlay_clock_gating(struct drm_i915_private *dev_priv,
 
 static void intel_overlay_submit_request(struct intel_overlay *overlay,
 					 struct i915_request *rq,
-					 i915_gem_retire_fn retire)
+					 i915_active_retire_fn retire)
 {
-	GEM_BUG_ON(i915_gem_active_peek(&overlay->last_flip,
-					&overlay->i915->drm.struct_mutex));
-	i915_gem_active_set_retire_fn(&overlay->last_flip, retire,
-				      &overlay->i915->drm.struct_mutex);
-	i915_gem_active_set(&overlay->last_flip, rq);
+	GEM_BUG_ON(i915_active_request_peek(&overlay->last_flip,
+					    &overlay->i915->drm.struct_mutex));
+	i915_active_request_set_retire_fn(&overlay->last_flip, retire,
+					  &overlay->i915->drm.struct_mutex);
+	__i915_active_request_set(&overlay->last_flip, rq);
 	i915_request_add(rq);
 }
 
 static int intel_overlay_do_wait_request(struct intel_overlay *overlay,
 					 struct i915_request *rq,
-					 i915_gem_retire_fn retire)
+					 i915_active_retire_fn retire)
 {
 	intel_overlay_submit_request(overlay, rq, retire);
-	return i915_gem_active_retire(&overlay->last_flip,
-				      &overlay->i915->drm.struct_mutex);
+	return i915_active_request_retire(&overlay->last_flip,
+					  &overlay->i915->drm.struct_mutex);
 }
 
 static struct i915_request *alloc_request(struct intel_overlay *overlay)
@@ -349,8 +349,9 @@ static void intel_overlay_release_old_vma(struct intel_overlay *overlay)
 	i915_vma_put(vma);
 }
 
-static void intel_overlay_release_old_vid_tail(struct i915_gem_active *active,
-					       struct i915_request *rq)
+static void
+intel_overlay_release_old_vid_tail(struct i915_active_request *active,
+				   struct i915_request *rq)
 {
 	struct intel_overlay *overlay =
 		container_of(active, typeof(*overlay), last_flip);
@@ -358,7 +359,7 @@ static void intel_overlay_release_old_vid_tail(struct i915_gem_active *active,
 	intel_overlay_release_old_vma(overlay);
 }
 
-static void intel_overlay_off_tail(struct i915_gem_active *active,
+static void intel_overlay_off_tail(struct i915_active_request *active,
 				   struct i915_request *rq)
 {
 	struct intel_overlay *overlay =
@@ -421,8 +422,8 @@ static int intel_overlay_off(struct intel_overlay *overlay)
  * We have to be careful not to repeat work forever an make forward progess. */
 static int intel_overlay_recover_from_interrupt(struct intel_overlay *overlay)
 {
-	return i915_gem_active_retire(&overlay->last_flip,
-				      &overlay->i915->drm.struct_mutex);
+	return i915_active_request_retire(&overlay->last_flip,
+					  &overlay->i915->drm.struct_mutex);
 }
 
 /* Wait for pending overlay flip and release old frame.
@@ -1355,7 +1356,7 @@ void intel_overlay_setup(struct drm_i915_private *dev_priv)
 	overlay->contrast = 75;
 	overlay->saturation = 146;
 
-	init_request_active(&overlay->last_flip, NULL);
+	INIT_ACTIVE_REQUEST(&overlay->last_flip);
 
 	mutex_lock(&dev_priv->drm.struct_mutex);
 

drivers/gpu/drm/i915/selftests/mock_timeline.c

@@ -15,8 +15,8 @@ void mock_timeline_init(struct i915_timeline *timeline, u64 context)
 
 	spin_lock_init(&timeline->lock);
 
-	init_request_active(&timeline->barrier, NULL);
-	init_request_active(&timeline->last_request, NULL);
+	INIT_ACTIVE_REQUEST(&timeline->barrier);
+	INIT_ACTIVE_REQUEST(&timeline->last_request);
 	INIT_LIST_HEAD(&timeline->requests);
 
 	i915_syncmap_init(&timeline->sync);