drm/i915: Use a single page table lock for each gtt.

We may create page table objects on the fly, but we may need to
wait with the ww lock held. Instead of waiting on a freed obj
lock, ensure we have the same lock for each object to keep
-EDEADLK working. This ensures that i915_vma_pin_ww can lock
the page tables when required.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-41-maarten.lankhorst@linux.intel.com

1 files changed, 37 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index 444d9bacfafd..941f8af016d6 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -13,16 +13,36 @@
 
 struct drm_i915_gem_object *alloc_pt_dma(struct i915_address_space *vm, int sz)
 {
+	struct drm_i915_gem_object *obj;
+
 	if (I915_SELFTEST_ONLY(should_fail(&vm->fault_attr, 1)))
 		i915_gem_shrink_all(vm->i915);
 
-	return i915_gem_object_create_internal(vm->i915, sz);
+	obj = i915_gem_object_create_internal(vm->i915, sz);
+	/* ensure all dma objects have the same reservation class */
+	if (!IS_ERR(obj))
+		obj->base.resv = &vm->resv;
+	return obj;
 }
 
 int pin_pt_dma(struct i915_address_space *vm, struct drm_i915_gem_object *obj)
 {
 	int err;
 
+	i915_gem_object_lock(obj, NULL);
+	err = i915_gem_object_pin_pages(obj);
+	i915_gem_object_unlock(obj);
+	if (err)
+		return err;
+
+	i915_gem_object_make_unshrinkable(obj);
+	return 0;
+}
+
+int pin_pt_dma_locked(struct i915_address_space *vm, struct drm_i915_gem_object *obj)
+{
+	int err;
+
 	err = i915_gem_object_pin_pages(obj);
 	if (err)
 		return err;
@@ -56,6 +76,20 @@ void __i915_vm_close(struct i915_address_space *vm)
 	mutex_unlock(&vm->mutex);
 }
 
+/* lock the vm into the current ww, if we lock one, we lock all */
+int i915_vm_lock_objects(struct i915_address_space *vm,
+			 struct i915_gem_ww_ctx *ww)
+{
+	if (vm->scratch[0]->base.resv == &vm->resv) {
+		return i915_gem_object_lock(vm->scratch[0], ww);
+	} else {
+		struct i915_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
+
+		/* We borrowed the scratch page from ggtt, take the top level object */
+		return i915_gem_object_lock(ppgtt->pd->pt.base, ww);
+	}
+}
+
 void i915_address_space_fini(struct i915_address_space *vm)
 {
 	drm_mm_takedown(&vm->mm);
@@ -69,6 +103,7 @@ static void __i915_vm_release(struct work_struct *work)
 
 	vm->cleanup(vm);
 	i915_address_space_fini(vm);
+	dma_resv_fini(&vm->resv);
 
 	kfree(vm);
 }
@@ -98,6 +133,7 @@ void i915_address_space_init(struct i915_address_space *vm, int subclass)
 	mutex_init(&vm->mutex);
 	lockdep_set_subclass(&vm->mutex, subclass);
 	i915_gem_shrinker_taints_mutex(vm->i915, &vm->mutex);
+	dma_resv_init(&vm->resv);
 
 	GEM_BUG_ON(!vm->total);
 	drm_mm_init(&vm->mm, 0, vm->total);