qxl: convert qxl driver to proper use for reservations

The recent addition of lockdep support to reservations and their subsequent
use by TTM showed up a number of potential problems with the way qxl was using
TTM objects.

a) it was allocating objects, and reserving them later without validating
underneath the reservation, which meant in extreme conditions the objects could
be evicted before the reservation ever used them.

b) it was reserving objects straight after allocating them, but with no
ability to back off should the reservations fail. It now allocates the necessary
objects then does a complete reservation pass on them to avoid deadlocks.

c) it had two lists per release tracking objects, unnecessary complicating
the reservation process.

This patch removes the dual object tracking, adds reservations ticket support
to the release and fence object handling. It then ports the internal fb
drawing code and the userspace facing ioctl to use the new interfaces properly,
along with cleanup up the error path handling in some codepaths.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 17 insertions, 23 deletions

diff --git a/drivers/gpu/drm/qxl/qxl_cmd.c b/drivers/gpu/drm/qxl/qxl_cmd.c
index 4e6a62716618..eb89653a7a17 100644
--- a/drivers/gpu/drm/qxl/qxl_cmd.c
+++ b/drivers/gpu/drm/qxl/qxl_cmd.c
@@ -179,9 +179,10 @@ qxl_push_command_ring_release(struct qxl_device *qdev, struct qxl_release *relea
 			      uint32_t type, bool interruptible)
 {
 	struct qxl_command cmd;
+	struct qxl_bo_list *entry = list_first_entry(&release->bos, struct qxl_bo_list, tv.head);
 
 	cmd.type = type;
-	cmd.data = qxl_bo_physical_address(qdev, release->bos[0], release->release_offset);
+	cmd.data = qxl_bo_physical_address(qdev, to_qxl_bo(entry->tv.bo), release->release_offset);
 
 	return qxl_ring_push(qdev->command_ring, &cmd, interruptible);
 }
@@ -191,9 +192,10 @@ qxl_push_cursor_ring_release(struct qxl_device *qdev, struct qxl_release *releas
 			     uint32_t type, bool interruptible)
 {
 	struct qxl_command cmd;
+	struct qxl_bo_list *entry = list_first_entry(&release->bos, struct qxl_bo_list, tv.head);
 
 	cmd.type = type;
-	cmd.data = qxl_bo_physical_address(qdev, release->bos[0], release->release_offset);
+	cmd.data = qxl_bo_physical_address(qdev, to_qxl_bo(entry->tv.bo), release->release_offset);
 
 	return qxl_ring_push(qdev->cursor_ring, &cmd, interruptible);
 }
@@ -214,7 +216,6 @@ int qxl_garbage_collect(struct qxl_device *qdev)
 	struct qxl_release *release;
 	uint64_t id, next_id;
 	int i = 0;
-	int ret;
 	union qxl_release_info *info;
 
 	while (qxl_ring_pop(qdev->release_ring, &id)) {
@@ -224,17 +225,10 @@ int qxl_garbage_collect(struct qxl_device *qdev)
 			if (release == NULL)
 				break;
 
-			ret = qxl_release_reserve(qdev, release, false);
-			if (ret) {
-				qxl_io_log(qdev, "failed to reserve release on garbage collect %lld\n", id);
-				DRM_ERROR("failed to reserve release %lld\n", id);
-			}
-
 			info = qxl_release_map(qdev, release);
 			next_id = info->next;
 			qxl_release_unmap(qdev, release, info);
 
-			qxl_release_unreserve(qdev, release);
 			QXL_INFO(qdev, "popped %lld, next %lld\n", id,
 				next_id);
 
@@ -259,7 +253,9 @@ int qxl_garbage_collect(struct qxl_device *qdev)
 	return i;
 }
 
-int qxl_alloc_bo_reserved(struct qxl_device *qdev, unsigned long size,
+int qxl_alloc_bo_reserved(struct qxl_device *qdev,
+			  struct qxl_release *release,
+			  unsigned long size,
 			  struct qxl_bo **_bo)
 {
 	struct qxl_bo *bo;
@@ -271,15 +267,15 @@ int qxl_alloc_bo_reserved(struct qxl_device *qdev, unsigned long size,
 		DRM_ERROR("failed to allocate VRAM BO\n");
 		return ret;
 	}
-	ret = qxl_bo_reserve(bo, false);
-	if (unlikely(ret != 0))
+	ret = qxl_release_list_add(release, bo);
+	if (ret)
 		goto out_unref;
 
 	*_bo = bo;
 	return 0;
 out_unref:
 	qxl_bo_unref(&bo);
-	return 0;
+	return ret;
 }
 
 static int wait_for_io_cmd_user(struct qxl_device *qdev, uint8_t val, long port, bool intr)
@@ -503,6 +499,10 @@ int qxl_hw_surface_alloc(struct qxl_device *qdev,
 	if (ret)
 		return ret;
 
+	ret = qxl_release_reserve_list(release, true);
+	if (ret)
+		return ret;
+
 	cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
 	cmd->type = QXL_SURFACE_CMD_CREATE;
 	cmd->u.surface_create.format = surf->surf.format;
@@ -524,14 +524,11 @@ int qxl_hw_surface_alloc(struct qxl_device *qdev,
 
 	surf->surf_create = release;
 
-	/* no need to add a release to the fence for this bo,
+	/* no need to add a release to the fence for this surface bo,
 	   since it is only released when we ask to destroy the surface
 	   and it would never signal otherwise */
-	qxl_fence_releaseable(qdev, release);
-
 	qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
-
-	qxl_release_unreserve(qdev, release);
+	qxl_release_fence_buffer_objects(release);
 
 	surf->hw_surf_alloc = true;
 	spin_lock(&qdev->surf_id_idr_lock);
@@ -573,12 +570,9 @@ int qxl_hw_surface_dealloc(struct qxl_device *qdev,
 	cmd->surface_id = id;
 	qxl_release_unmap(qdev, release, &cmd->release_info);
 
-	qxl_fence_releaseable(qdev, release);
-
 	qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
 
-	qxl_release_unreserve(qdev, release);
-
+	qxl_release_fence_buffer_objects(release);
 
 	return 0;
 }