drm/ttm: make ttm reservation calls behave like reservation calls

This commit converts the source of the val_seq counter to
the ww_mutex api. The reservation objects are converted later,
because there is still a lockdep splat in nouveau that has to
resolved first.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/nouveau/nouveau_gem.c

@@ -277,10 +277,12 @@ struct validate_op {
 	struct list_head vram_list;
 	struct list_head gart_list;
 	struct list_head both_list;
+	struct ww_acquire_ctx ticket;
 };
 
 static void
-validate_fini_list(struct list_head *list, struct nouveau_fence *fence)
+validate_fini_list(struct list_head *list, struct nouveau_fence *fence,
+		   struct ww_acquire_ctx *ticket)
 {
 	struct list_head *entry, *tmp;
 	struct nouveau_bo *nvbo;
@@ -297,17 +299,24 @@ validate_fini_list(struct list_head *list, struct nouveau_fence *fence)
 
 		list_del(&nvbo->entry);
 		nvbo->reserved_by = NULL;
-		ttm_bo_unreserve(&nvbo->bo);
+		ttm_bo_unreserve_ticket(&nvbo->bo, ticket);
 		drm_gem_object_unreference_unlocked(nvbo->gem);
 	}
 }
 
 static void
-validate_fini(struct validate_op *op, struct nouveau_fence* fence)
+validate_fini_no_ticket(struct validate_op *op, struct nouveau_fence *fence)
 {
-	validate_fini_list(&op->vram_list, fence);
-	validate_fini_list(&op->gart_list, fence);
-	validate_fini_list(&op->both_list, fence);
+	validate_fini_list(&op->vram_list, fence, &op->ticket);
+	validate_fini_list(&op->gart_list, fence, &op->ticket);
+	validate_fini_list(&op->both_list, fence, &op->ticket);
+}
+
+static void
+validate_fini(struct validate_op *op, struct nouveau_fence *fence)
+{
+	validate_fini_no_ticket(op, fence);
+	ww_acquire_fini(&op->ticket);
 }
 
 static int
@@ -317,13 +326,11 @@ validate_init(struct nouveau_channel *chan, struct drm_file *file_priv,
 {
 	struct nouveau_cli *cli = nouveau_cli(file_priv);
 	struct drm_device *dev = chan->drm->dev;
-	struct nouveau_drm *drm = nouveau_drm(dev);
-	uint32_t sequence;
 	int trycnt = 0;
 	int ret, i;
 	struct nouveau_bo *res_bo = NULL;
 
-	sequence = atomic_add_return(1, &drm->ttm.validate_sequence);
+	ww_acquire_init(&op->ticket, &reservation_ww_class);
 retry:
 	if (++trycnt > 100000) {
 		NV_ERROR(cli, "%s failed and gave up.\n", __func__);
@@ -338,6 +345,7 @@ validate_init(struct nouveau_channel *chan, struct drm_file *file_priv,
 		gem = drm_gem_object_lookup(dev, file_priv, b->handle);
 		if (!gem) {
 			NV_ERROR(cli, "Unknown handle 0x%08x\n", b->handle);
+			ww_acquire_done(&op->ticket);
 			validate_fini(op, NULL);
 			return -ENOENT;
 		}
@@ -352,21 +360,23 @@ validate_init(struct nouveau_channel *chan, struct drm_file *file_priv,
 			NV_ERROR(cli, "multiple instances of buffer %d on "
 				      "validation list\n", b->handle);
 			drm_gem_object_unreference_unlocked(gem);
+			ww_acquire_done(&op->ticket);
 			validate_fini(op, NULL);
 			return -EINVAL;
 		}
 
-		ret = ttm_bo_reserve(&nvbo->bo, true, false, true, sequence);
+		ret = ttm_bo_reserve(&nvbo->bo, true, false, true, &op->ticket);
 		if (ret) {
-			validate_fini(op, NULL);
+			validate_fini_no_ticket(op, NULL);
 			if (unlikely(ret == -EAGAIN)) {
-				sequence = atomic_add_return(1, &drm->ttm.validate_sequence);
 				ret = ttm_bo_reserve_slowpath(&nvbo->bo, true,
-							      sequence);
+							      &op->ticket);
 				if (!ret)
 					res_bo = nvbo;
 			}
 			if (unlikely(ret)) {
+				ww_acquire_done(&op->ticket);
+				ww_acquire_fini(&op->ticket);
 				drm_gem_object_unreference_unlocked(gem);
 				if (ret != -ERESTARTSYS)
 					NV_ERROR(cli, "fail reserve\n");
@@ -390,6 +400,7 @@ validate_init(struct nouveau_channel *chan, struct drm_file *file_priv,
 			NV_ERROR(cli, "invalid valid domains: 0x%08x\n",
 				 b->valid_domains);
 			list_add_tail(&nvbo->entry, &op->both_list);
+			ww_acquire_done(&op->ticket);
 			validate_fini(op, NULL);
 			return -EINVAL;
 		}
@@ -397,6 +408,7 @@ validate_init(struct nouveau_channel *chan, struct drm_file *file_priv,
 			goto retry;
 	}
 
+	ww_acquire_done(&op->ticket);
 	return 0;
 }
 

drivers/gpu/drm/radeon/radeon.h

@@ -979,6 +979,7 @@ struct radeon_cs_parser {
 	u32			cs_flags;
 	u32			ring;
 	s32			priority;
+	struct ww_acquire_ctx	ticket;
 };
 
 extern int radeon_cs_finish_pages(struct radeon_cs_parser *p);

drivers/gpu/drm/radeon/radeon_cs.c

@@ -106,7 +106,7 @@ static int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
 		radeon_bo_list_add_object(&p->relocs[i].lobj,
 					  &p->validated);
 	}
-	return radeon_bo_list_validate(&p->validated, p->ring);
+	return radeon_bo_list_validate(&p->ticket, &p->validated, p->ring);
 }
 
 static int radeon_cs_get_ring(struct radeon_cs_parser *p, u32 ring, s32 priority)
@@ -314,15 +314,17 @@ int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
  * If error is set than unvalidate buffer, otherwise just free memory
  * used by parsing context.
  **/
-static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error)
+static void radeon_cs_parser_fini(struct radeon_cs_parser *parser, int error, bool backoff)
 {
 	unsigned i;
 
 	if (!error) {
-		ttm_eu_fence_buffer_objects(&parser->validated,
+		ttm_eu_fence_buffer_objects(&parser->ticket,
+					    &parser->validated,
 					    parser->ib.fence);
-	} else {
-		ttm_eu_backoff_reservation(&parser->validated);
+	} else if (backoff) {
+		ttm_eu_backoff_reservation(&parser->ticket,
+					   &parser->validated);
 	}
 
 	if (parser->relocs != NULL) {
@@ -535,7 +537,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 	r = radeon_cs_parser_init(&parser, data);
 	if (r) {
 		DRM_ERROR("Failed to initialize parser !\n");
-		radeon_cs_parser_fini(&parser, r);
+		radeon_cs_parser_fini(&parser, r, false);
 		up_read(&rdev->exclusive_lock);
 		r = radeon_cs_handle_lockup(rdev, r);
 		return r;
@@ -544,7 +546,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 	if (r) {
 		if (r != -ERESTARTSYS)
 			DRM_ERROR("Failed to parse relocation %d!\n", r);
-		radeon_cs_parser_fini(&parser, r);
+		radeon_cs_parser_fini(&parser, r, false);
 		up_read(&rdev->exclusive_lock);
 		r = radeon_cs_handle_lockup(rdev, r);
 		return r;
@@ -563,7 +565,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
 		goto out;
 	}
 out:
-	radeon_cs_parser_fini(&parser, r);
+	radeon_cs_parser_fini(&parser, r, true);
 	up_read(&rdev->exclusive_lock);
 	r = radeon_cs_handle_lockup(rdev, r);
 	return r;

drivers/gpu/drm/radeon/radeon_object.c

@@ -349,14 +349,15 @@ void radeon_bo_list_add_object(struct radeon_bo_list *lobj,
 	}
 }
 
-int radeon_bo_list_validate(struct list_head *head, int ring)
+int radeon_bo_list_validate(struct ww_acquire_ctx *ticket,
+			    struct list_head *head, int ring)
 {
 	struct radeon_bo_list *lobj;
 	struct radeon_bo *bo;
 	u32 domain;
 	int r;
 
-	r = ttm_eu_reserve_buffers(head);
+	r = ttm_eu_reserve_buffers(ticket, head);
 	if (unlikely(r != 0)) {
 		return r;
 	}

drivers/gpu/drm/radeon/radeon_object.h

@@ -128,7 +128,8 @@ extern int radeon_bo_init(struct radeon_device *rdev);
 extern void radeon_bo_fini(struct radeon_device *rdev);
 extern void radeon_bo_list_add_object(struct radeon_bo_list *lobj,
 				struct list_head *head);
-extern int radeon_bo_list_validate(struct list_head *head, int ring);
+extern int radeon_bo_list_validate(struct ww_acquire_ctx *ticket,
+				   struct list_head *head, int ring);
 extern int radeon_bo_fbdev_mmap(struct radeon_bo *bo,
 				struct vm_area_struct *vma);
 extern int radeon_bo_set_tiling_flags(struct radeon_bo *bo,

drivers/gpu/drm/radeon/radeon_uvd.c

@@ -550,6 +550,7 @@ static int radeon_uvd_send_msg(struct radeon_device *rdev,
 			       struct radeon_fence **fence)
 {
 	struct ttm_validate_buffer tv;
+	struct ww_acquire_ctx ticket;
 	struct list_head head;
 	struct radeon_ib ib;
 	uint64_t addr;
@@ -561,7 +562,7 @@ static int radeon_uvd_send_msg(struct radeon_device *rdev,
 	INIT_LIST_HEAD(&head);
 	list_add(&tv.head, &head);
 
-	r = ttm_eu_reserve_buffers(&head);
+	r = ttm_eu_reserve_buffers(&ticket, &head);
 	if (r)
 		return r;
 
@@ -569,16 +570,12 @@ static int radeon_uvd_send_msg(struct radeon_device *rdev,
 	radeon_uvd_force_into_uvd_segment(bo);
 
 	r = ttm_bo_validate(&bo->tbo, &bo->placement, true, false);
-	if (r) {
-		ttm_eu_backoff_reservation(&head);
-		return r;
-	}
+	if (r) 
+		goto err;
 
 	r = radeon_ib_get(rdev, ring, &ib, NULL, 16);
-	if (r) {
-		ttm_eu_backoff_reservation(&head);
-		return r;
-	}
+	if (r)
+		goto err;
 
 	addr = radeon_bo_gpu_offset(bo);
 	ib.ptr[0] = PACKET0(UVD_GPCOM_VCPU_DATA0, 0);
@@ -592,11 +589,9 @@ static int radeon_uvd_send_msg(struct radeon_device *rdev,
 	ib.length_dw = 16;
 
 	r = radeon_ib_schedule(rdev, &ib, NULL);
-	if (r) {
-		ttm_eu_backoff_reservation(&head);
-		return r;
-	}
-	ttm_eu_fence_buffer_objects(&head, ib.fence);
+	if (r)
+		goto err;
+	ttm_eu_fence_buffer_objects(&ticket, &head, ib.fence);
 
 	if (fence)
 		*fence = radeon_fence_ref(ib.fence);
@@ -604,6 +599,10 @@ static int radeon_uvd_send_msg(struct radeon_device *rdev,
 	radeon_ib_free(rdev, &ib);
 	radeon_bo_unref(&bo);
 	return 0;
+
+err:
+	ttm_eu_backoff_reservation(&ticket, &head);
+	return r;
 }
 
 /* multiple fence commands without any stream commands in between can

drivers/gpu/drm/ttm/ttm_bo.c

@@ -215,7 +215,8 @@ int ttm_bo_del_from_lru(struct ttm_buffer_object *bo)
 
 int ttm_bo_reserve_nolru(struct ttm_buffer_object *bo,
 			  bool interruptible,
-			  bool no_wait, bool use_sequence, uint32_t sequence)
+			  bool no_wait, bool use_ticket,
+			  struct ww_acquire_ctx *ticket)
 {
 	int ret;
 
@@ -223,17 +224,17 @@ int ttm_bo_reserve_nolru(struct ttm_buffer_object *bo,
 		/**
 		 * Deadlock avoidance for multi-bo reserving.
 		 */
-		if (use_sequence && bo->seq_valid) {
+		if (use_ticket && bo->seq_valid) {
 			/**
 			 * We've already reserved this one.
 			 */
-			if (unlikely(sequence == bo->val_seq))
+			if (unlikely(ticket->stamp == bo->val_seq))
 				return -EDEADLK;
 			/**
 			 * Already reserved by a thread that will not back
 			 * off for us. We need to back off.
 			 */
-			if (unlikely(sequence - bo->val_seq < (1 << 31)))
+			if (unlikely(ticket->stamp - bo->val_seq <= LONG_MAX))
 				return -EAGAIN;
 		}
 
@@ -246,13 +247,14 @@ int ttm_bo_reserve_nolru(struct ttm_buffer_object *bo,
 			return ret;
 	}
 
-	if (use_sequence) {
+	if (use_ticket) {
 		bool wake_up = false;
+
 		/**
 		 * Wake up waiters that may need to recheck for deadlock,
 		 * if we decreased the sequence number.
 		 */
-		if (unlikely((bo->val_seq - sequence < (1 << 31))
+		if (unlikely((bo->val_seq - ticket->stamp <= LONG_MAX)
 			     || !bo->seq_valid))
 			wake_up = true;
 
@@ -266,7 +268,7 @@ int ttm_bo_reserve_nolru(struct ttm_buffer_object *bo,
 		 * written before val_seq was, and just means some slightly
 		 * increased cpu usage
 		 */
-		bo->val_seq = sequence;
+		bo->val_seq = ticket->stamp;
 		bo->seq_valid = true;
 		if (wake_up)
 			wake_up_all(&bo->event_queue);
@@ -292,14 +294,15 @@ void ttm_bo_list_ref_sub(struct ttm_buffer_object *bo, int count,
 
 int ttm_bo_reserve(struct ttm_buffer_object *bo,
 		   bool interruptible,
-		   bool no_wait, bool use_sequence, uint32_t sequence)
+		   bool no_wait, bool use_ticket,
+		   struct ww_acquire_ctx *ticket)
 {
 	struct ttm_bo_global *glob = bo->glob;
 	int put_count = 0;
 	int ret;
 
-	ret = ttm_bo_reserve_nolru(bo, interruptible, no_wait, use_sequence,
-				   sequence);
+	ret = ttm_bo_reserve_nolru(bo, interruptible, no_wait, use_ticket,
+				    ticket);
 	if (likely(ret == 0)) {
 		spin_lock(&glob->lru_lock);
 		put_count = ttm_bo_del_from_lru(bo);
@@ -311,13 +314,14 @@ int ttm_bo_reserve(struct ttm_buffer_object *bo,
 }
 
 int ttm_bo_reserve_slowpath_nolru(struct ttm_buffer_object *bo,
-				  bool interruptible, uint32_t sequence)
+				  bool interruptible,
+				  struct ww_acquire_ctx *ticket)
 {
 	bool wake_up = false;
 	int ret;
 
 	while (unlikely(atomic_xchg(&bo->reserved, 1) != 0)) {
-		WARN_ON(bo->seq_valid && sequence == bo->val_seq);
+		WARN_ON(bo->seq_valid && ticket->stamp == bo->val_seq);
 
 		ret = ttm_bo_wait_unreserved(bo, interruptible);
 
@@ -325,14 +329,14 @@ int ttm_bo_reserve_slowpath_nolru(struct ttm_buffer_object *bo,
 			return ret;
 	}
 
-	if ((bo->val_seq - sequence < (1 << 31)) || !bo->seq_valid)
+	if (bo->val_seq - ticket->stamp < LONG_MAX || !bo->seq_valid)
 		wake_up = true;
 
 	/**
 	 * Wake up waiters that may need to recheck for deadlock,
 	 * if we decreased the sequence number.
 	 */
-	bo->val_seq = sequence;
+	bo->val_seq = ticket->stamp;
 	bo->seq_valid = true;
 	if (wake_up)
 		wake_up_all(&bo->event_queue);
@@ -341,12 +345,12 @@ int ttm_bo_reserve_slowpath_nolru(struct ttm_buffer_object *bo,
 }
 
 int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
-			    bool interruptible, uint32_t sequence)
+			    bool interruptible, struct ww_acquire_ctx *ticket)
 {
 	struct ttm_bo_global *glob = bo->glob;
 	int put_count, ret;
 
-	ret = ttm_bo_reserve_slowpath_nolru(bo, interruptible, sequence);
+	ret = ttm_bo_reserve_slowpath_nolru(bo, interruptible, ticket);
 	if (likely(!ret)) {
 		spin_lock(&glob->lru_lock);
 		put_count = ttm_bo_del_from_lru(bo);
@@ -357,7 +361,7 @@ int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
 }
 EXPORT_SYMBOL(ttm_bo_reserve_slowpath);
 
-void ttm_bo_unreserve_locked(struct ttm_buffer_object *bo)
+void ttm_bo_unreserve_ticket_locked(struct ttm_buffer_object *bo, struct ww_acquire_ctx *ticket)
 {
 	ttm_bo_add_to_lru(bo);
 	atomic_set(&bo->reserved, 0);
@@ -369,11 +373,21 @@ void ttm_bo_unreserve(struct ttm_buffer_object *bo)
 	struct ttm_bo_global *glob = bo->glob;
 
 	spin_lock(&glob->lru_lock);
-	ttm_bo_unreserve_locked(bo);
+	ttm_bo_unreserve_ticket_locked(bo, NULL);
 	spin_unlock(&glob->lru_lock);
 }
 EXPORT_SYMBOL(ttm_bo_unreserve);
 
+void ttm_bo_unreserve_ticket(struct ttm_buffer_object *bo, struct ww_acquire_ctx *ticket)
+{
+	struct ttm_bo_global *glob = bo->glob;
+
+	spin_lock(&glob->lru_lock);
+	ttm_bo_unreserve_ticket_locked(bo, ticket);
+	spin_unlock(&glob->lru_lock);
+}
+EXPORT_SYMBOL(ttm_bo_unreserve_ticket);
+
 /*
  * Call bo->mutex locked.
  */

drivers/gpu/drm/ttm/ttm_execbuf_util.c

@@ -32,7 +32,8 @@
 #include <linux/sched.h>
 #include <linux/module.h>
 
-static void ttm_eu_backoff_reservation_locked(struct list_head *list)
+static void ttm_eu_backoff_reservation_locked(struct list_head *list,
+					      struct ww_acquire_ctx *ticket)
 {
 	struct ttm_validate_buffer *entry;
 
@@ -41,15 +42,16 @@ static void ttm_eu_backoff_reservation_locked(struct list_head *list)
 		if (!entry->reserved)
 			continue;
 
+		entry->reserved = false;
 		if (entry->removed) {
-			ttm_bo_add_to_lru(bo);
+			ttm_bo_unreserve_ticket_locked(bo, ticket);
 			entry->removed = false;
 
-		}
-		entry->reserved = false;
+		} else {
 			atomic_set(&bo->reserved, 0);
 			wake_up_all(&bo->event_queue);
 		}
+	}
 }
 
 static void ttm_eu_del_from_lru_locked(struct list_head *list)
@@ -82,7 +84,8 @@ static void ttm_eu_list_ref_sub(struct list_head *list)
 	}
 }
 
-void ttm_eu_backoff_reservation(struct list_head *list)
+void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
+				struct list_head *list)
 {
 	struct ttm_validate_buffer *entry;
 	struct ttm_bo_global *glob;
@@ -93,7 +96,8 @@ void ttm_eu_backoff_reservation(struct list_head *list)
 	entry = list_first_entry(list, struct ttm_validate_buffer, head);
 	glob = entry->bo->glob;
 	spin_lock(&glob->lru_lock);
-	ttm_eu_backoff_reservation_locked(list);
+	ttm_eu_backoff_reservation_locked(list, ticket);
+	ww_acquire_fini(ticket);
 	spin_unlock(&glob->lru_lock);
 }
 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
@@ -110,12 +114,12 @@ EXPORT_SYMBOL(ttm_eu_backoff_reservation);
  * buffers in different orders.
  */
 
-int ttm_eu_reserve_buffers(struct list_head *list)
+int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
+			   struct list_head *list)
 {
 	struct ttm_bo_global *glob;
 	struct ttm_validate_buffer *entry;
 	int ret;
-	uint32_t val_seq;
 
 	if (list_empty(list))
 		return 0;
@@ -129,8 +133,8 @@ int ttm_eu_reserve_buffers(struct list_head *list)
 	entry = list_first_entry(list, struct ttm_validate_buffer, head);
 	glob = entry->bo->glob;
 
+	ww_acquire_init(ticket, &reservation_ww_class);
 	spin_lock(&glob->lru_lock);
-	val_seq = entry->bo->bdev->val_seq++;
 
 retry:
 	list_for_each_entry(entry, list, head) {
@@ -140,7 +144,7 @@ int ttm_eu_reserve_buffers(struct list_head *list)
 		if (entry->reserved)
 			continue;
 
-		ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq);
+		ret = ttm_bo_reserve_nolru(bo, true, true, true, ticket);
 		switch (ret) {
 		case 0:
 			break;
@@ -148,8 +152,9 @@ int ttm_eu_reserve_buffers(struct list_head *list)
 			ttm_eu_del_from_lru_locked(list);
 			spin_unlock(&glob->lru_lock);
 			ret = ttm_bo_reserve_nolru(bo, true, false,
-						   true, val_seq);
+						   true, ticket);
 			spin_lock(&glob->lru_lock);
+
 			if (!ret)
 				break;
 
@@ -158,21 +163,13 @@ int ttm_eu_reserve_buffers(struct list_head *list)
 
 			/* fallthrough */
 		case -EAGAIN:
-			ttm_eu_backoff_reservation_locked(list);
-
-			/*
-			 * temporarily increase sequence number every retry,
-			 * to prevent us from seeing our old reservation
-			 * sequence when someone else reserved the buffer,
-			 * but hasn't updated the seq_valid/seqno members yet.
-			 */
-			val_seq = entry->bo->bdev->val_seq++;
-
+			ttm_eu_backoff_reservation_locked(list, ticket);
 			spin_unlock(&glob->lru_lock);
 			ttm_eu_list_ref_sub(list);
-			ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq);
+			ret = ttm_bo_reserve_slowpath_nolru(bo, true, ticket);
 			if (unlikely(ret != 0))
-				return ret;
+				goto err_fini;
+
 			spin_lock(&glob->lru_lock);
 			entry->reserved = true;
 			if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
@@ -191,21 +188,25 @@ int ttm_eu_reserve_buffers(struct list_head *list)
 		}
 	}
 
+	ww_acquire_done(ticket);
 	ttm_eu_del_from_lru_locked(list);
 	spin_unlock(&glob->lru_lock);
 	ttm_eu_list_ref_sub(list);
-
 	return 0;
 
 err:
-	ttm_eu_backoff_reservation_locked(list);
+	ttm_eu_backoff_reservation_locked(list, ticket);
 	spin_unlock(&glob->lru_lock);
 	ttm_eu_list_ref_sub(list);
+err_fini:
+	ww_acquire_done(ticket);
+	ww_acquire_fini(ticket);
 	return ret;
 }
 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 
-void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
+void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
+				 struct list_head *list, void *sync_obj)
 {
 	struct ttm_validate_buffer *entry;
 	struct ttm_buffer_object *bo;
@@ -228,11 +229,12 @@ void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
 		bo = entry->bo;
 		entry->old_sync_obj = bo->sync_obj;
 		bo->sync_obj = driver->sync_obj_ref(sync_obj);
-		ttm_bo_unreserve_locked(bo);
+		ttm_bo_unreserve_ticket_locked(bo, ticket);
 		entry->reserved = false;
 	}
 	spin_unlock(&bdev->fence_lock);
 	spin_unlock(&glob->lru_lock);
+	ww_acquire_fini(ticket);
 
 	list_for_each_entry(entry, list, head) {
 		if (entry->old_sync_obj)

drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c

@@ -1432,6 +1432,7 @@ int vmw_execbuf_process(struct drm_file *file_priv,
 	struct vmw_fence_obj *fence = NULL;
 	struct vmw_resource *error_resource;
 	struct list_head resource_list;
+	struct ww_acquire_ctx ticket;
 	uint32_t handle;
 	void *cmd;
 	int ret;
@@ -1488,7 +1489,7 @@ int vmw_execbuf_process(struct drm_file *file_priv,
 	if (unlikely(ret != 0))
 		goto out_err;
 
-	ret = ttm_eu_reserve_buffers(&sw_context->validate_nodes);
+	ret = ttm_eu_reserve_buffers(&ticket, &sw_context->validate_nodes);
 	if (unlikely(ret != 0))
 		goto out_err;
 
@@ -1537,7 +1538,7 @@ int vmw_execbuf_process(struct drm_file *file_priv,
 		DRM_ERROR("Fence submission error. Syncing.\n");
 
 	vmw_resource_list_unreserve(&sw_context->resource_list, false);
-	ttm_eu_fence_buffer_objects(&sw_context->validate_nodes,
+	ttm_eu_fence_buffer_objects(&ticket, &sw_context->validate_nodes,
 				    (void *) fence);
 
 	if (unlikely(dev_priv->pinned_bo != NULL &&
@@ -1570,7 +1571,7 @@ int vmw_execbuf_process(struct drm_file *file_priv,
 out_err:
 	vmw_resource_relocations_free(&sw_context->res_relocations);
 	vmw_free_relocations(sw_context);
-	ttm_eu_backoff_reservation(&sw_context->validate_nodes);
+	ttm_eu_backoff_reservation(&ticket, &sw_context->validate_nodes);
 	vmw_resource_list_unreserve(&sw_context->resource_list, true);
 	vmw_clear_validations(sw_context);
 	if (unlikely(dev_priv->pinned_bo != NULL &&
@@ -1644,6 +1645,7 @@ void __vmw_execbuf_release_pinned_bo(struct vmw_private *dev_priv,
 	struct list_head validate_list;
 	struct ttm_validate_buffer pinned_val, query_val;
 	struct vmw_fence_obj *lfence = NULL;
+	struct ww_acquire_ctx ticket;
 
 	if (dev_priv->pinned_bo == NULL)
 		goto out_unlock;
@@ -1657,7 +1659,7 @@ void __vmw_execbuf_release_pinned_bo(struct vmw_private *dev_priv,
 	list_add_tail(&query_val.head, &validate_list);
 
 	do {
-		ret = ttm_eu_reserve_buffers(&validate_list);
+		ret = ttm_eu_reserve_buffers(&ticket, &validate_list);
 	} while (ret == -ERESTARTSYS);
 
 	if (unlikely(ret != 0)) {
@@ -1684,7 +1686,7 @@ void __vmw_execbuf_release_pinned_bo(struct vmw_private *dev_priv,
 						  NULL);
 		fence = lfence;
 	}
-	ttm_eu_fence_buffer_objects(&validate_list, (void *) fence);
+	ttm_eu_fence_buffer_objects(&ticket, &validate_list, (void *) fence);
 	if (lfence != NULL)
 		vmw_fence_obj_unreference(&lfence);
 
@@ -1696,7 +1698,7 @@ void __vmw_execbuf_release_pinned_bo(struct vmw_private *dev_priv,
 	return;
 
 out_no_emit:
-	ttm_eu_backoff_reservation(&validate_list);
+	ttm_eu_backoff_reservation(&ticket, &validate_list);
 out_no_reserve:
 	ttm_bo_unref(&query_val.bo);
 	ttm_bo_unref(&pinned_val.bo);

drivers/gpu/drm/vmwgfx/vmwgfx_resource.c

@@ -990,7 +990,9 @@ void vmw_resource_unreserve(struct vmw_resource *res,
  * @val_buf:        On successful return contains data about the
  *                  reserved and validated backup buffer.
  */
-int vmw_resource_check_buffer(struct vmw_resource *res,
+static int
+vmw_resource_check_buffer(struct vmw_resource *res,
+			  struct ww_acquire_ctx *ticket,
 			  bool interruptible,
 			  struct ttm_validate_buffer *val_buf)
 {
@@ -1007,7 +1009,7 @@ int vmw_resource_check_buffer(struct vmw_resource *res,
 	INIT_LIST_HEAD(&val_list);
 	val_buf->bo = ttm_bo_reference(&res->backup->base);
 	list_add_tail(&val_buf->head, &val_list);
-	ret = ttm_eu_reserve_buffers(&val_list);
+	ret = ttm_eu_reserve_buffers(ticket, &val_list);
 	if (unlikely(ret != 0))
 		goto out_no_reserve;
 
@@ -1025,7 +1027,7 @@ int vmw_resource_check_buffer(struct vmw_resource *res,
 	return 0;
 
 out_no_validate:
-	ttm_eu_backoff_reservation(&val_list);
+	ttm_eu_backoff_reservation(ticket, &val_list);
 out_no_reserve:
 	ttm_bo_unref(&val_buf->bo);
 	if (backup_dirty)
@@ -1069,7 +1071,9 @@ int vmw_resource_reserve(struct vmw_resource *res, bool no_backup)
  *.
  * @val_buf:        Backup buffer information.
  */
-void vmw_resource_backoff_reservation(struct ttm_validate_buffer *val_buf)
+static void
+vmw_resource_backoff_reservation(struct ww_acquire_ctx *ticket,
+				 struct ttm_validate_buffer *val_buf)
 {
 	struct list_head val_list;
 
@@ -1078,7 +1082,7 @@ void vmw_resource_backoff_reservation(struct ttm_validate_buffer *val_buf)
 
 	INIT_LIST_HEAD(&val_list);
 	list_add_tail(&val_buf->head, &val_list);
-	ttm_eu_backoff_reservation(&val_list);
+	ttm_eu_backoff_reservation(ticket, &val_list);
 	ttm_bo_unref(&val_buf->bo);
 }
 
@@ -1092,12 +1096,13 @@ int vmw_resource_do_evict(struct vmw_resource *res)
 {
 	struct ttm_validate_buffer val_buf;
 	const struct vmw_res_func *func = res->func;
+	struct ww_acquire_ctx ticket;
 	int ret;
 
 	BUG_ON(!func->may_evict);
 
 	val_buf.bo = NULL;
-	ret = vmw_resource_check_buffer(res, true, &val_buf);
+	ret = vmw_resource_check_buffer(res, &ticket, true, &val_buf);
 	if (unlikely(ret != 0))
 		return ret;
 
@@ -1112,7 +1117,7 @@ int vmw_resource_do_evict(struct vmw_resource *res)
 	res->backup_dirty = true;
 	res->res_dirty = false;
 out_no_unbind:
-	vmw_resource_backoff_reservation(&val_buf);
+	vmw_resource_backoff_reservation(&ticket, &val_buf);
 
 	return ret;
 }

include/drm/ttm/ttm_bo_api.h

@@ -234,7 +234,7 @@ struct ttm_buffer_object {
 	struct list_head ddestroy;
 	struct list_head swap;
 	struct list_head io_reserve_lru;
-	uint32_t val_seq;
+	unsigned long val_seq;
 	bool seq_valid;
 
 	/**

include/drm/ttm/ttm_bo_driver.h

@@ -38,6 +38,7 @@
 #include <linux/workqueue.h>
 #include <linux/fs.h>
 #include <linux/spinlock.h>
+#include <linux/reservation.h>
 
 struct ttm_backend_func {
 	/**
@@ -778,7 +779,7 @@ extern void ttm_mem_io_unlock(struct ttm_mem_type_manager *man);
  * @bo: A pointer to a struct ttm_buffer_object.
  * @interruptible: Sleep interruptible if waiting.
  * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
- * @use_sequence: If @bo is already reserved, Only sleep waiting for
+ * @use_ticket: If @bo is already reserved, Only sleep waiting for
  * it to become unreserved if @sequence < (@bo)->sequence.
  *
  * Locks a buffer object for validation. (Or prevents other processes from
@@ -819,7 +820,8 @@ extern void ttm_mem_io_unlock(struct ttm_mem_type_manager *man);
  */
 extern int ttm_bo_reserve(struct ttm_buffer_object *bo,
 			  bool interruptible,
-			  bool no_wait, bool use_sequence, uint32_t sequence);
+			  bool no_wait, bool use_ticket,
+			  struct ww_acquire_ctx *ticket);
 
 /**
  * ttm_bo_reserve_slowpath_nolru:
@@ -836,7 +838,7 @@ extern int ttm_bo_reserve(struct ttm_buffer_object *bo,
  */
 extern int ttm_bo_reserve_slowpath_nolru(struct ttm_buffer_object *bo,
 					 bool interruptible,
-					 uint32_t sequence);
+					 struct ww_acquire_ctx *ticket);
 
 
 /**
@@ -850,7 +852,8 @@ extern int ttm_bo_reserve_slowpath_nolru(struct ttm_buffer_object *bo,
  * held by us, this function cannot deadlock any more.
  */
 extern int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
-				   bool interruptible, uint32_t sequence);
+				   bool interruptible,
+				   struct ww_acquire_ctx *ticket);
 
 /**
  * ttm_bo_reserve_nolru:
@@ -876,8 +879,8 @@ extern int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
  */
 extern int ttm_bo_reserve_nolru(struct ttm_buffer_object *bo,
 				 bool interruptible,
-				 bool no_wait, bool use_sequence,
-				 uint32_t sequence);
+				 bool no_wait, bool use_ticket,
+				 struct ww_acquire_ctx *ticket);
 
 /**
  * ttm_bo_unreserve
@@ -889,14 +892,25 @@ extern int ttm_bo_reserve_nolru(struct ttm_buffer_object *bo,
 extern void ttm_bo_unreserve(struct ttm_buffer_object *bo);
 
 /**
- * ttm_bo_unreserve_locked
+ * ttm_bo_unreserve_ticket
+ * @bo: A pointer to a struct ttm_buffer_object.
+ * @ticket: ww_acquire_ctx used for reserving
  *
+ * Unreserve a previous reservation of @bo made with @ticket.
+ */
+extern void ttm_bo_unreserve_ticket(struct ttm_buffer_object *bo,
+				    struct ww_acquire_ctx *ticket);
+
+/**
+ * ttm_bo_unreserve_locked
  * @bo: A pointer to a struct ttm_buffer_object.
+ * @ticket: ww_acquire_ctx used for reserving, or NULL
  *
- * Unreserve a previous reservation of @bo.
+ * Unreserve a previous reservation of @bo made with @ticket.
  * Needs to be called with struct ttm_bo_global::lru_lock held.
  */
-extern void ttm_bo_unreserve_locked(struct ttm_buffer_object *bo);
+extern void ttm_bo_unreserve_ticket_locked(struct ttm_buffer_object *bo,
+					   struct ww_acquire_ctx *ticket);
 
 /*
  * ttm_bo_util.c

include/drm/ttm/ttm_execbuf_util.h

@@ -33,6 +33,7 @@
 
 #include <ttm/ttm_bo_api.h>
 #include <linux/list.h>
+#include <linux/reservation.h>
 
 /**
  * struct ttm_validate_buffer
@@ -57,17 +58,20 @@ struct ttm_validate_buffer {
 /**
  * function ttm_eu_backoff_reservation
  *
+ * @ticket:   ww_acquire_ctx from reserve call
  * @list:     thread private list of ttm_validate_buffer structs.
  *
  * Undoes all buffer validation reservations for bos pointed to by
  * the list entries.
  */
 
-extern void ttm_eu_backoff_reservation(struct list_head *list);
+extern void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
+				       struct list_head *list);
 
 /**
  * function ttm_eu_reserve_buffers
  *
+ * @ticket:  [out] ww_acquire_ctx returned by call.
  * @list:    thread private list of ttm_validate_buffer structs.
  *
  * Tries to reserve bos pointed to by the list entries for validation.
@@ -90,11 +94,13 @@ extern void ttm_eu_backoff_reservation(struct list_head *list);
  * has failed.
  */
 
-extern int ttm_eu_reserve_buffers(struct list_head *list);
+extern int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
+				  struct list_head *list);
 
 /**
  * function ttm_eu_fence_buffer_objects.
  *
+ * @ticket:      ww_acquire_ctx from reserve call
  * @list:        thread private list of ttm_validate_buffer structs.
  * @sync_obj:    The new sync object for the buffers.
  *
@@ -104,6 +110,7 @@ extern int ttm_eu_reserve_buffers(struct list_head *list);
  *
  */
 
-extern void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj);
+extern void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
+					struct list_head *list, void *sync_obj);
 
 #endif