drm/i915: Pull VM lists under the VM mutex.

A starting point to counter the pervasive struct_mutex. For the goal of
avoiding (or at least blocking under them!) global locks during user
request submission, a simple but important step is being able to manage
each clients GTT separately. For which, we want to replace using the
struct_mutex as the guard for all things GTT/VM and switch instead to a
specific mutex inside i915_address_space.
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/20190128102356.15037-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -245,18 +245,19 @@ int
 i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
 			    struct drm_file *file)
 {
-	struct drm_i915_private *dev_priv = to_i915(dev);
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
+	struct i915_ggtt *ggtt = &to_i915(dev)->ggtt;
 	struct drm_i915_gem_get_aperture *args = data;
 	struct i915_vma *vma;
 	u64 pinned;
 
+	mutex_lock(&ggtt->vm.mutex);
+
 	pinned = ggtt->vm.reserved;
-	mutex_lock(&dev->struct_mutex);
 	list_for_each_entry(vma, &ggtt->vm.bound_list, vm_link)
 		if (i915_vma_is_pinned(vma))
 			pinned += vma->node.size;
-	mutex_unlock(&dev->struct_mutex);
+
+	mutex_unlock(&ggtt->vm.mutex);
 
 	args->aper_size = ggtt->vm.total;
 	args->aper_available_size = args->aper_size - pinned;
@@ -1529,20 +1530,21 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
 
 static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj)
 {
-	struct drm_i915_private *i915;
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct list_head *list;
 	struct i915_vma *vma;
 
 	GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
 
+	mutex_lock(&i915->ggtt.vm.mutex);
 	for_each_ggtt_vma(vma, obj) {
 		if (!drm_mm_node_allocated(&vma->node))
 			continue;
 
 		list_move_tail(&vma->vm_link, &vma->vm->bound_list);
 	}
+	mutex_unlock(&i915->ggtt.vm.mutex);
 
-	i915 = to_i915(obj->base.dev);
 	spin_lock(&i915->mm.obj_lock);
 	list = obj->bind_count ? &i915->mm.bound_list : &i915->mm.unbound_list;
 	list_move_tail(&obj->mm.link, list);

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -430,6 +430,7 @@ int i915_gem_evict_vm(struct i915_address_space *vm)
 	}
 
 	INIT_LIST_HEAD(&eviction_list);
+	mutex_lock(&vm->mutex);
 	list_for_each_entry(vma, &vm->bound_list, vm_link) {
 		if (i915_vma_is_pinned(vma))
 			continue;
@@ -437,6 +438,7 @@ int i915_gem_evict_vm(struct i915_address_space *vm)
 		__i915_vma_pin(vma);
 		list_add(&vma->evict_link, &eviction_list);
 	}
+	mutex_unlock(&vm->mutex);
 
 	ret = 0;
 	list_for_each_entry_safe(vma, next, &eviction_list, evict_link) {

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -1931,7 +1931,10 @@ static struct i915_vma *pd_vma_create(struct gen6_hw_ppgtt *ppgtt, int size)
 	vma->ggtt_view.type = I915_GGTT_VIEW_ROTATED; /* prevent fencing */
 
 	INIT_LIST_HEAD(&vma->obj_link);
+
+	mutex_lock(&vma->vm->mutex);
 	list_add(&vma->vm_link, &vma->vm->unbound_list);
+	mutex_unlock(&vma->vm->mutex);
 
 	return vma;
 }
@@ -3504,9 +3507,10 @@ void i915_gem_restore_gtt_mappings(struct drm_i915_private *dev_priv)
 
 	i915_check_and_clear_faults(dev_priv);
 
+	mutex_lock(&ggtt->vm.mutex);
+
 	/* First fill our portion of the GTT with scratch pages */
 	ggtt->vm.clear_range(&ggtt->vm, 0, ggtt->vm.total);
-
 	ggtt->vm.closed = true; /* skip rewriting PTE on VMA unbind */
 
 	/* clflush objects bound into the GGTT and rebind them. */
@@ -3516,19 +3520,26 @@ void i915_gem_restore_gtt_mappings(struct drm_i915_private *dev_priv)
 		if (!(vma->flags & I915_VMA_GLOBAL_BIND))
 			continue;
 
+		mutex_unlock(&ggtt->vm.mutex);
+
 		if (!i915_vma_unbind(vma))
-			continue;
+			goto lock;
 
 		WARN_ON(i915_vma_bind(vma,
 				      obj ? obj->cache_level : 0,
 				      PIN_UPDATE));
 		if (obj)
 			WARN_ON(i915_gem_object_set_to_gtt_domain(obj, false));
+
+lock:
+		mutex_lock(&ggtt->vm.mutex);
 	}
 
 	ggtt->vm.closed = false;
 	i915_ggtt_invalidate(dev_priv);
 
+	mutex_unlock(&ggtt->vm.mutex);
+
 	if (INTEL_GEN(dev_priv) >= 8) {
 		struct intel_ppat *ppat = &dev_priv->ppat;
 

drivers/gpu/drm/i915/i915_gem_shrinker.c

@@ -461,6 +461,7 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr
 					       I915_SHRINK_VMAPS);
 
 	/* We also want to clear any cached iomaps as they wrap vmap */
+	mutex_lock(&i915->ggtt.vm.mutex);
 	list_for_each_entry_safe(vma, next,
 				 &i915->ggtt.vm.bound_list, vm_link) {
 		unsigned long count = vma->node.size >> PAGE_SHIFT;
@@ -468,9 +469,12 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr
 		if (!vma->iomap || i915_vma_is_active(vma))
 			continue;
 
+		mutex_unlock(&i915->ggtt.vm.mutex);
 		if (i915_vma_unbind(vma) == 0)
 			freed_pages += count;
+		mutex_lock(&i915->ggtt.vm.mutex);
 	}
+	mutex_unlock(&i915->ggtt.vm.mutex);
 
 out:
 	shrinker_unlock(i915, unlock);

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -702,7 +702,9 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_i915_private *dev_priv
 	vma->flags |= I915_VMA_GLOBAL_BIND;
 	__i915_vma_set_map_and_fenceable(vma);
 
+	mutex_lock(&ggtt->vm.mutex);
 	list_move_tail(&vma->vm_link, &ggtt->vm.bound_list);
+	mutex_unlock(&ggtt->vm.mutex);
 
 	spin_lock(&dev_priv->mm.obj_lock);
 	list_move_tail(&obj->mm.link, &dev_priv->mm.bound_list);

drivers/gpu/drm/i915/i915_vma.c

@@ -213,7 +213,10 @@ vma_create(struct drm_i915_gem_object *obj,
 	}
 	rb_link_node(&vma->obj_node, rb, p);
 	rb_insert_color(&vma->obj_node, &obj->vma_tree);
+
+	mutex_lock(&vm->mutex);
 	list_add(&vma->vm_link, &vm->unbound_list);
+	mutex_unlock(&vm->mutex);
 
 	return vma;
 
@@ -656,7 +659,9 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
 	GEM_BUG_ON(!i915_gem_valid_gtt_space(vma, cache_level));
 
+	mutex_lock(&vma->vm->mutex);
 	list_move_tail(&vma->vm_link, &vma->vm->bound_list);
+	mutex_unlock(&vma->vm->mutex);
 
 	if (vma->obj) {
 		struct drm_i915_gem_object *obj = vma->obj;
@@ -689,8 +694,10 @@ i915_vma_remove(struct i915_vma *vma)
 
 	vma->ops->clear_pages(vma);
 
+	mutex_lock(&vma->vm->mutex);
 	drm_mm_remove_node(&vma->node);
 	list_move_tail(&vma->vm_link, &vma->vm->unbound_list);
+	mutex_unlock(&vma->vm->mutex);
 
 	/*
 	 * Since the unbound list is global, only move to that list if
@@ -802,7 +809,11 @@ static void __i915_vma_destroy(struct i915_vma *vma)
 	GEM_BUG_ON(i915_gem_active_isset(&vma->last_fence));
 
 	list_del(&vma->obj_link);
+
+	mutex_lock(&vma->vm->mutex);
 	list_del(&vma->vm_link);
+	mutex_unlock(&vma->vm->mutex);
+
 	if (vma->obj)
 		rb_erase(&vma->obj_node, &vma->obj->vma_tree);
 

drivers/gpu/drm/i915/selftests/i915_gem_evict.c

@@ -94,11 +94,14 @@ static int populate_ggtt(struct drm_i915_private *i915,
 
 static void unpin_ggtt(struct drm_i915_private *i915)
 {
+	struct i915_ggtt *ggtt = &i915->ggtt;
 	struct i915_vma *vma;
 
+	mutex_lock(&ggtt->vm.mutex);
 	list_for_each_entry(vma, &i915->ggtt.vm.bound_list, vm_link)
 		if (vma->obj->mm.quirked)
 			i915_vma_unpin(vma);
+	mutex_unlock(&ggtt->vm.mutex);
 }
 
 static void cleanup_objects(struct drm_i915_private *i915,

drivers/gpu/drm/i915/selftests/i915_gem_gtt.c

@@ -1237,7 +1237,10 @@ static void track_vma_bind(struct i915_vma *vma)
 	__i915_gem_object_pin_pages(obj);
 
 	vma->pages = obj->mm.pages;
+
+	mutex_lock(&vma->vm->mutex);
 	list_move_tail(&vma->vm_link, &vma->vm->bound_list);
+	mutex_unlock(&vma->vm->mutex);
 }
 
 static int exercise_mock(struct drm_i915_private *i915,