[PATCH v2 2/2] drm/amdgpu: Add CHANGE_ID option for USERQ ioctl

Add a new option to the USERQ ioctl, which is called with
the queue_id of an existing user queue and an unused queue_id,
and changes that queue's id to the new value.

Calling with an invalid new handle will fail. Calling with new_handle
=handle will succeed if that queue exists but not do anything.

This operation holds userq_mutex and the userq_xa xa_lock for its
entire duration.

Performing this operation on a queue with signals or waits
outstanding is fine, as those hold not the queue_id but a
direct reference to the queue object.

Signed-off-by: David Francis <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 43 +++++++++++++++++++++++
 include/uapi/drm/amdgpu_drm.h             | 17 +++++++--
 2 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
index 3c930425c1bb..b532ba0f4cef 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
@@ -852,6 +852,11 @@ static int amdgpu_userq_input_args_validate(struct drm_device *dev,
 		break;
 	case AMDGPU_USERQ_OP_LIST:
 		break;
+	case AMDGPU_USERQ_OP_CHANGE_ID:
+		if (!args->change_in.new_queue_id ||
+		    args->change_in.new_queue_id > AMDGPU_MAX_USERQ_COUNT)
+			return -EINVAL;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -1012,6 +1017,41 @@ amdgpu_userq_list(struct drm_file *filp, union drm_amdgpu_userq *args)
 	return ret;
 }
 
+static int amdgpu_userq_change_id(struct drm_file *filp, union drm_amdgpu_userq *args)
+{
+	struct amdgpu_fpriv *fpriv = filp->driver_priv;
+	struct amdgpu_userq_mgr *uq_mgr = &fpriv->userq_mgr;
+	struct amdgpu_usermode_queue *queue;
+	int ret = 0;
+
+	mutex_lock(&uq_mgr->userq_mutex);
+	xa_lock(&uq_mgr->userq_xa);
+
+	queue = xa_load(&uq_mgr->userq_xa, args->change_in.queue_id);
+	if (!queue) {
+		ret = -ENOENT;
+		goto unlock;
+	}
+
+	if (args->change_in.new_queue_id == args->change_in.queue_id) {
+		ret = 0;
+		goto unlock;
+	}
+
+	ret = __xa_insert(&uq_mgr->userq_xa, args->change_in.new_queue_id, queue, GFP_KERNEL);
+	if (ret) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	__xa_erase(&uq_mgr->userq_xa, args->change_in.queue_id);
+
+unlock:
+	xa_unlock(&uq_mgr->userq_xa);
+	mutex_unlock(&uq_mgr->userq_mutex);
+	return ret;
+}
+
 bool amdgpu_userq_enabled(struct drm_device *dev)
 {
 	struct amdgpu_device *adev = drm_to_adev(dev);
@@ -1058,6 +1098,9 @@ int amdgpu_userq_ioctl(struct drm_device *dev, void *data,
 	case AMDGPU_USERQ_OP_LIST:
 		r = amdgpu_userq_list(filp, args);
 		break;
+	case AMDGPU_USERQ_OP_CHANGE_ID:
+		r = amdgpu_userq_change_id(filp, args);
+		break;
 	default:
 		drm_dbg_driver(dev, "Invalid user queue op specified: %d\n", args->in.op);
 		return -EINVAL;
diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index 678f3d531df7..de9ae1296819 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -330,9 +330,10 @@ union drm_amdgpu_ctx {
 };
 
 /* user queue IOCTL operations */
-#define AMDGPU_USERQ_OP_CREATE	1
-#define AMDGPU_USERQ_OP_FREE	2
-#define AMDGPU_USERQ_OP_LIST	3
+#define AMDGPU_USERQ_OP_CREATE		1
+#define AMDGPU_USERQ_OP_FREE		2
+#define AMDGPU_USERQ_OP_LIST		3
+#define AMDGPU_USERQ_OP_CHANGE_ID	4
 
 /* queue priority levels */
 /* low < normal low < normal high < high */
@@ -463,10 +464,20 @@ struct drm_amdgpu_userq_list_in_out {
 	__u64   entries;
 };
 
+struct drm_amdgpu_userq_change_id_in {
+	/** AMDGPU_USERQ_OP_CHANGE_ID */
+	__u32   op;
+	/** Queue id of some queue */
+	__u32   queue_id;
+	/** Queue id to change that queue to */
+	__u32   new_queue_id;
+};
+
 union drm_amdgpu_userq {
 	struct drm_amdgpu_userq_in in;
 	struct drm_amdgpu_userq_out out;
 	struct drm_amdgpu_userq_list_in_out list_in_out;
+	struct drm_amdgpu_userq_change_id_in change_in;
 };
 
 /* GFX V11 IP specific MQD parameters */
-- 
2.34.1