drm/i915: Only track bound elements of the GTT

The premise here is to simply avoiding having to acquire the vm->mutex
inside vma create/destroy to update the vm->unbound_lists, to avoid some
nasty lock recursions later.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-2-chris@chris-wilson.co.uk

1 files changed, 4 insertions, 19 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index e62e9d1a1307..ad9eb2d68f3f 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -505,19 +505,12 @@ static void i915_address_space_fini(struct i915_address_space *vm)
 
 static void ppgtt_destroy_vma(struct i915_address_space *vm)
 {
-	struct list_head *phases[] = {
-		&vm->bound_list,
-		&vm->unbound_list,
-		NULL,
-	}, **phase;
+	struct i915_vma *vma, *vn;
 
 	mutex_lock(&vm->i915->drm.struct_mutex);
-	for (phase = phases; *phase; phase++) {
-		struct i915_vma *vma, *vn;
-
-		list_for_each_entry_safe(vma, vn, *phase, vm_link)
-			i915_vma_destroy(vma);
-	}
+	list_for_each_entry_safe(vma, vn, &vm->bound_list, vm_link)
+		i915_vma_destroy(vma);
+	GEM_BUG_ON(!list_empty(&vm->bound_list));
 	mutex_unlock(&vm->i915->drm.struct_mutex);
 }
 
@@ -528,9 +521,6 @@ static void __i915_vm_release(struct work_struct *work)
 
 	ppgtt_destroy_vma(vm);
 
-	GEM_BUG_ON(!list_empty(&vm->bound_list));
-	GEM_BUG_ON(!list_empty(&vm->unbound_list));
-
 	vm->cleanup(vm);
 	i915_address_space_fini(vm);
 
@@ -569,7 +559,6 @@ static void i915_address_space_init(struct i915_address_space *vm, int subclass)
 
 	stash_init(&vm->free_pages);
 
-	INIT_LIST_HEAD(&vm->unbound_list);
 	INIT_LIST_HEAD(&vm->bound_list);
 }
 
@@ -1887,10 +1876,6 @@ static struct i915_vma *pd_vma_create(struct gen6_ppgtt *ppgtt, int size)
 	INIT_LIST_HEAD(&vma->obj_link);
 	INIT_LIST_HEAD(&vma->closed_link);
 
-	mutex_lock(&vma->vm->mutex);
-	list_add(&vma->vm_link, &vma->vm->unbound_list);
-	mutex_unlock(&vma->vm->mutex);
-
 	return vma;
 }