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, 174 insertions, 143 deletions

diff --git a/drivers/gpu/drm/qxl/qxl_ioctl.c b/drivers/gpu/drm/qxl/qxl_ioctl.c
index 7448c5ea92e6..6de33563d6f1 100644
--- a/drivers/gpu/drm/qxl/qxl_ioctl.c
+++ b/drivers/gpu/drm/qxl/qxl_ioctl.c
@@ -68,55 +68,60 @@ static int qxl_map_ioctl(struct drm_device *dev, void *data,
 				  &qxl_map->offset);
 }
 
+struct qxl_reloc_info {
+	int type;
+	struct qxl_bo *dst_bo;
+	uint32_t dst_offset;
+	struct qxl_bo *src_bo;
+	int src_offset;
+};
+
 /*
  * dst must be validated, i.e. whole bo on vram/surfacesram (right now all bo's
  * are on vram).
  * *(dst + dst_off) = qxl_bo_physical_address(src, src_off)
  */
 static void
-apply_reloc(struct qxl_device *qdev, struct qxl_bo *dst, uint64_t dst_off,
-	    struct qxl_bo *src, uint64_t src_off)
+apply_reloc(struct qxl_device *qdev, struct qxl_reloc_info *info)
 {
 	void *reloc_page;
-
-	reloc_page = qxl_bo_kmap_atomic_page(qdev, dst, dst_off & PAGE_MASK);
-	*(uint64_t *)(reloc_page + (dst_off & ~PAGE_MASK)) = qxl_bo_physical_address(qdev,
-								     src, src_off);
-	qxl_bo_kunmap_atomic_page(qdev, dst, reloc_page);
+	reloc_page = qxl_bo_kmap_atomic_page(qdev, info->dst_bo, info->dst_offset & PAGE_MASK);
+	*(uint64_t *)(reloc_page + (info->dst_offset & ~PAGE_MASK)) = qxl_bo_physical_address(qdev,
+											      info->src_bo,
+											      info->src_offset);
+	qxl_bo_kunmap_atomic_page(qdev, info->dst_bo, reloc_page);
 }
 
 static void
-apply_surf_reloc(struct qxl_device *qdev, struct qxl_bo *dst, uint64_t dst_off,
-		 struct qxl_bo *src)
+apply_surf_reloc(struct qxl_device *qdev, struct qxl_reloc_info *info)
 {
 	uint32_t id = 0;
 	void *reloc_page;
 
-	if (src && !src->is_primary)
-		id = src->surface_id;
+	if (info->src_bo && !info->src_bo->is_primary)
+		id = info->src_bo->surface_id;
 
-	reloc_page = qxl_bo_kmap_atomic_page(qdev, dst, dst_off & PAGE_MASK);
-	*(uint32_t *)(reloc_page + (dst_off & ~PAGE_MASK)) = id;
-	qxl_bo_kunmap_atomic_page(qdev, dst, reloc_page);
+	reloc_page = qxl_bo_kmap_atomic_page(qdev, info->dst_bo, info->dst_offset & PAGE_MASK);
+	*(uint32_t *)(reloc_page + (info->dst_offset & ~PAGE_MASK)) = id;
+	qxl_bo_kunmap_atomic_page(qdev, info->dst_bo, reloc_page);
 }
 
 /* return holding the reference to this object */
 static struct qxl_bo *qxlhw_handle_to_bo(struct qxl_device *qdev,
 					 struct drm_file *file_priv, uint64_t handle,
-					 struct qxl_reloc_list *reloc_list)
+					 struct qxl_release *release)
 {
 	struct drm_gem_object *gobj;
 	struct qxl_bo *qobj;
 	int ret;
 
 	gobj = drm_gem_object_lookup(qdev->ddev, file_priv, handle);
-	if (!gobj) {
-		DRM_ERROR("bad bo handle %lld\n", handle);
+	if (!gobj)
 		return NULL;
-	}
+
 	qobj = gem_to_qxl_bo(gobj);
 
-	ret = qxl_bo_list_add(reloc_list, qobj);
+	ret = qxl_release_list_add(release, qobj);
 	if (ret)
 		return NULL;
 
@@ -129,151 +134,177 @@ static struct qxl_bo *qxlhw_handle_to_bo(struct qxl_device *qdev,
  * However, the command as passed from user space must *not* contain the initial
  * QXLReleaseInfo struct (first XXX bytes)
  */
-static int qxl_execbuffer_ioctl(struct drm_device *dev, void *data,
-				struct drm_file *file_priv)
+static int qxl_process_single_command(struct qxl_device *qdev,
+				      struct drm_qxl_command *cmd,
+				      struct drm_file *file_priv)
 {
-	struct qxl_device *qdev = dev->dev_private;
-	struct drm_qxl_execbuffer *execbuffer = data;
-	struct drm_qxl_command user_cmd;
-	int cmd_num;
-	struct qxl_bo *reloc_src_bo;
-	struct qxl_bo *reloc_dst_bo;
-	struct drm_qxl_reloc reloc;
+	struct qxl_reloc_info *reloc_info;
+	int release_type;
+	struct qxl_release *release;
+	struct qxl_bo *cmd_bo;
 	void *fb_cmd;
-	int i, ret;
-	struct qxl_reloc_list reloc_list;
+	int i, j, ret, num_relocs;
 	int unwritten;
-	uint32_t reloc_dst_offset;
-	INIT_LIST_HEAD(&reloc_list.bos);
 
-	for (cmd_num = 0; cmd_num < execbuffer->commands_num; ++cmd_num) {
-		struct qxl_release *release;
-		struct qxl_bo *cmd_bo;
-		int release_type;
-		struct drm_qxl_command *commands =
-			(struct drm_qxl_command *)(uintptr_t)execbuffer->commands;
+	switch (cmd->type) {
+	case QXL_CMD_DRAW:
+		release_type = QXL_RELEASE_DRAWABLE;
+		break;
+	case QXL_CMD_SURFACE:
+	case QXL_CMD_CURSOR:
+	default:
+		DRM_DEBUG("Only draw commands in execbuffers\n");
+		return -EINVAL;
+		break;
+	}
 
-		if (DRM_COPY_FROM_USER(&user_cmd, &commands[cmd_num],
-				       sizeof(user_cmd)))
-			return -EFAULT;
-		switch (user_cmd.type) {
-		case QXL_CMD_DRAW:
-			release_type = QXL_RELEASE_DRAWABLE;
-			break;
-		case QXL_CMD_SURFACE:
-		case QXL_CMD_CURSOR:
-		default:
-			DRM_DEBUG("Only draw commands in execbuffers\n");
-			return -EINVAL;
-			break;
-		}
+	if (cmd->command_size > PAGE_SIZE - sizeof(union qxl_release_info))
+		return -EINVAL;
 
-		if (user_cmd.command_size > PAGE_SIZE - sizeof(union qxl_release_info))
-			return -EINVAL;
+	if (!access_ok(VERIFY_READ,
+		       (void *)(unsigned long)cmd->command,
+		       cmd->command_size))
+		return -EFAULT;
 
-		if (!access_ok(VERIFY_READ,
-			       (void *)(unsigned long)user_cmd.command,
-			       user_cmd.command_size))
-			return -EFAULT;
+	reloc_info = kmalloc(sizeof(struct qxl_reloc_info) * cmd->relocs_num, GFP_KERNEL);
+	if (!reloc_info)
+		return -ENOMEM;
 
-		ret = qxl_alloc_release_reserved(qdev,
-						 sizeof(union qxl_release_info) +
-						 user_cmd.command_size,
-						 release_type,
-						 &release,
-						 &cmd_bo);
-		if (ret)
-			return ret;
+	ret = qxl_alloc_release_reserved(qdev,
+					 sizeof(union qxl_release_info) +
+					 cmd->command_size,
+					 release_type,
+					 &release,
+					 &cmd_bo);
+	if (ret)
+		goto out_free_reloc;
 
-		/* TODO copy slow path code from i915 */
-		fb_cmd = qxl_bo_kmap_atomic_page(qdev, cmd_bo, (release->release_offset & PAGE_SIZE));
-		unwritten = __copy_from_user_inatomic_nocache(fb_cmd + sizeof(union qxl_release_info) + (release->release_offset & ~PAGE_SIZE), (void *)(unsigned long)user_cmd.command, user_cmd.command_size);
+	/* TODO copy slow path code from i915 */
+	fb_cmd = qxl_bo_kmap_atomic_page(qdev, cmd_bo, (release->release_offset & PAGE_SIZE));
+	unwritten = __copy_from_user_inatomic_nocache(fb_cmd + sizeof(union qxl_release_info) + (release->release_offset & ~PAGE_SIZE), (void *)(unsigned long)cmd->command, cmd->command_size);
 
-		{
-			struct qxl_drawable *draw = fb_cmd;
+	{
+		struct qxl_drawable *draw = fb_cmd;
+		draw->mm_time = qdev->rom->mm_clock;
+	}
 
-			draw->mm_time = qdev->rom->mm_clock;
-		}
-		qxl_bo_kunmap_atomic_page(qdev, cmd_bo, fb_cmd);
-		if (unwritten) {
-			DRM_ERROR("got unwritten %d\n", unwritten);
-			qxl_release_unreserve(qdev, release);
-			qxl_release_free(qdev, release);
-			return -EFAULT;
+	qxl_bo_kunmap_atomic_page(qdev, cmd_bo, fb_cmd);
+	if (unwritten) {
+		DRM_ERROR("got unwritten %d\n", unwritten);
+		ret = -EFAULT;
+		goto out_free_release;
+	}
+
+	/* fill out reloc info structs */
+	num_relocs = 0;
+	for (i = 0; i < cmd->relocs_num; ++i) {
+		struct drm_qxl_reloc reloc;
+
+		if (DRM_COPY_FROM_USER(&reloc,
+				       &((struct drm_qxl_reloc *)(uintptr_t)cmd->relocs)[i],
+				       sizeof(reloc))) {
+			ret = -EFAULT;
+			goto out_free_bos;
 		}
 
-		for (i = 0 ; i < user_cmd.relocs_num; ++i) {
-			if (DRM_COPY_FROM_USER(&reloc,
-					       &((struct drm_qxl_reloc *)(uintptr_t)user_cmd.relocs)[i],
-					       sizeof(reloc))) {
-				qxl_bo_list_unreserve(&reloc_list, true);
-				qxl_release_unreserve(qdev, release);
-				qxl_release_free(qdev, release);
-				return -EFAULT;
-			}
+		/* add the bos to the list of bos to validate -
+		   need to validate first then process relocs? */
+		if (reloc.reloc_type != QXL_RELOC_TYPE_BO && reloc.reloc_type != QXL_RELOC_TYPE_SURF) {
+			DRM_DEBUG("unknown reloc type %d\n", reloc_info[i].type);
 
-			/* add the bos to the list of bos to validate -
-			   need to validate first then process relocs? */
-			if (reloc.dst_handle) {
-				reloc_dst_bo = qxlhw_handle_to_bo(qdev, file_priv,
-								  reloc.dst_handle, &reloc_list);
-				if (!reloc_dst_bo) {
-					qxl_bo_list_unreserve(&reloc_list, true);
-					qxl_release_unreserve(qdev, release);
-					qxl_release_free(qdev, release);
-					return -EINVAL;
-				}
-				reloc_dst_offset = 0;
-			} else {
-				reloc_dst_bo = cmd_bo;
-				reloc_dst_offset = release->release_offset;
+			ret = -EINVAL;
+			goto out_free_bos;
+		}
+		reloc_info[i].type = reloc.reloc_type;
+
+		if (reloc.dst_handle) {
+			reloc_info[i].dst_bo = qxlhw_handle_to_bo(qdev, file_priv,
+								  reloc.dst_handle, release);
+			if (!reloc_info[i].dst_bo) {
+				ret = -EINVAL;
+				reloc_info[i].src_bo = NULL;
+				goto out_free_bos;
 			}
-
-			/* reserve and validate the reloc dst bo */
-			if (reloc.reloc_type == QXL_RELOC_TYPE_BO || reloc.src_handle > 0) {
-				reloc_src_bo =
-					qxlhw_handle_to_bo(qdev, file_priv,
-							   reloc.src_handle, &reloc_list);
-				if (!reloc_src_bo) {
-					if (reloc_dst_bo != cmd_bo)
-						drm_gem_object_unreference_unlocked(&reloc_dst_bo->gem_base);
-					qxl_bo_list_unreserve(&reloc_list, true);
-					qxl_release_unreserve(qdev, release);
-					qxl_release_free(qdev, release);
-					return -EINVAL;
-				}
-			} else
-				reloc_src_bo = NULL;
-			if (reloc.reloc_type == QXL_RELOC_TYPE_BO) {
-				apply_reloc(qdev, reloc_dst_bo, reloc_dst_offset + reloc.dst_offset,
-					    reloc_src_bo, reloc.src_offset);
-			} else if (reloc.reloc_type == QXL_RELOC_TYPE_SURF) {
-				apply_surf_reloc(qdev, reloc_dst_bo, reloc_dst_offset + reloc.dst_offset, reloc_src_bo);
-			} else {
-				DRM_ERROR("unknown reloc type %d\n", reloc.reloc_type);
-				return -EINVAL;
+			reloc_info[i].dst_offset = reloc.dst_offset;
+		} else {
+			reloc_info[i].dst_bo = cmd_bo;
+			reloc_info[i].dst_offset = reloc.dst_offset + release->release_offset;
+		}
+		num_relocs++;
+
+		/* reserve and validate the reloc dst bo */
+		if (reloc.reloc_type == QXL_RELOC_TYPE_BO || reloc.src_handle > 0) {
+			reloc_info[i].src_bo =
+				qxlhw_handle_to_bo(qdev, file_priv,
+						   reloc.src_handle, release);
+			if (!reloc_info[i].src_bo) {
+				if (reloc_info[i].dst_bo != cmd_bo)
+					drm_gem_object_unreference_unlocked(&reloc_info[i].dst_bo->gem_base);
+				ret = -EINVAL;
+				goto out_free_bos;
 			}
+			reloc_info[i].src_offset = reloc.src_offset;
+		} else {
+			reloc_info[i].src_bo = NULL;
+			reloc_info[i].src_offset = 0;
+		}
+	}
 
-			if (reloc_src_bo && reloc_src_bo != cmd_bo) {
-				qxl_release_add_res(qdev, release, reloc_src_bo);
-				drm_gem_object_unreference_unlocked(&reloc_src_bo->gem_base);
-			}
+	/* validate all buffers */
+	ret = qxl_release_reserve_list(release, false);
+	if (ret)
+		goto out_free_bos;
 
-			if (reloc_dst_bo != cmd_bo)
-				drm_gem_object_unreference_unlocked(&reloc_dst_bo->gem_base);
-		}
-		qxl_fence_releaseable(qdev, release);
+	for (i = 0; i < cmd->relocs_num; ++i) {
+		if (reloc_info[i].type == QXL_RELOC_TYPE_BO)
+			apply_reloc(qdev, &reloc_info[i]);
+		else if (reloc_info[i].type == QXL_RELOC_TYPE_SURF)
+			apply_surf_reloc(qdev, &reloc_info[i]);
+	}
 
-		ret = qxl_push_command_ring_release(qdev, release, user_cmd.type, true);
-		if (ret == -ERESTARTSYS) {
-			qxl_release_unreserve(qdev, release);
-			qxl_release_free(qdev, release);
-			qxl_bo_list_unreserve(&reloc_list, true);
+	ret = qxl_push_command_ring_release(qdev, release, cmd->type, true);
+	if (ret)
+		qxl_release_backoff_reserve_list(release);
+	else
+		qxl_release_fence_buffer_objects(release);
+
+out_free_bos:
+	for (j = 0; j < num_relocs; j++) {
+		if (reloc_info[j].dst_bo != cmd_bo)
+			drm_gem_object_unreference_unlocked(&reloc_info[j].dst_bo->gem_base);
+		if (reloc_info[j].src_bo && reloc_info[j].src_bo != cmd_bo)
+			drm_gem_object_unreference_unlocked(&reloc_info[j].src_bo->gem_base);
+	}
+out_free_release:
+	if (ret)
+		qxl_release_free(qdev, release);
+out_free_reloc:
+	kfree(reloc_info);
+	return ret;
+}
+
+static int qxl_execbuffer_ioctl(struct drm_device *dev, void *data,
+				struct drm_file *file_priv)
+{
+	struct qxl_device *qdev = dev->dev_private;
+	struct drm_qxl_execbuffer *execbuffer = data;
+	struct drm_qxl_command user_cmd;
+	int cmd_num;
+	int ret;
+
+	for (cmd_num = 0; cmd_num < execbuffer->commands_num; ++cmd_num) {
+
+		struct drm_qxl_command *commands =
+			(struct drm_qxl_command *)(uintptr_t)execbuffer->commands;
+
+		if (DRM_COPY_FROM_USER(&user_cmd, &commands[cmd_num],
+				       sizeof(user_cmd)))
+			return -EFAULT;
+
+		ret = qxl_process_single_command(qdev, &user_cmd, file_priv);
+		if (ret)
 			return ret;
-		}
-		qxl_release_unreserve(qdev, release);
 	}
-	qxl_bo_list_unreserve(&reloc_list, 0);
 	return 0;
 }