[PATCH 18/27] drm/i915: Make i915_gem_evict_vm work correctly for already locked objects

[Maarten Lankhorst]

i915_gem_execbuf will call i915_gem_evict_vm() after failing to pin
all objects in the first round. We are about to remove those short-term
pins, but even without those the objects are still locked. Add a special
case to allow i915_gem_evict_vm to evict locked objects as well.

This might also allow multiple objects sharing the same resv to be evicted.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem_evict.c | 30 +++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 6eac5238769b..514802eaaefa 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -432,6 +432,7 @@ int i915_gem_evict_vm(struct i915_address_space *vm, struct i915_gem_ww_ctx *ww)
 	do {
 		struct i915_vma *vma, *vn;
 		LIST_HEAD(eviction_list);
+		LIST_HEAD(locked_eviction_list);
 
 		list_for_each_entry(vma, &vm->bound_list, vm_link) {
 			if (i915_vma_is_pinned(vma))
@@ -440,18 +441,43 @@ int i915_gem_evict_vm(struct i915_address_space *vm, struct i915_gem_ww_ctx *ww)
 			if (!kref_get_unless_zero(&vma->obj->base.refcount))
 				continue;
 
+			__i915_vma_pin(vma);
+
+			/*
+			 * If we already own the lock, trylock fails. In case the resv
+			 * is shared among multiple objects, we still need the object ref.
+			 */
+			if (ww && (dma_resv_locking_ctx(vma->obj->base.resv) == &ww->ctx)) {
+				list_add(&vma->evict_link, &locked_eviction_list);
+				continue;
+			}
+
 			if (!i915_gem_object_trylock(vma->obj, ww)) {
+				__i915_vma_unpin(vma);
 				i915_gem_object_put(vma->obj);
 				continue;
 			}
 
-			__i915_vma_pin(vma);
 			list_add(&vma->evict_link, &eviction_list);
 		}
-		if (list_empty(&eviction_list))
+		if (list_empty(&eviction_list) && list_empty(&locked_eviction_list))
 			break;
 
 		ret = 0;
+		/* Unbind locked objects first, before unlocking the eviction_list */
+		list_for_each_entry_safe(vma, vn, &locked_eviction_list, evict_link) {
+			struct drm_i915_gem_object *obj = vma->obj;
+
+			__i915_vma_unpin(vma);
+
+			if (ret == 0)
+				ret = __i915_vma_unbind(vma);
+			if (ret != -EINTR) /* "Get me out of here!" */
+				ret = 0;
+
+			i915_gem_object_put(obj);
+		}
+
 		list_for_each_entry_safe(vma, vn, &eviction_list, evict_link) {
 			struct drm_i915_gem_object *obj = vma->obj;
 
-- 
2.33.0