backend/drm: introduce wlr_drm_lease

Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3183

backend/drm/drm.c

@@ -1554,17 +1554,13 @@ int wlr_drm_backend_get_non_master_fd(struct wlr_backend *backend) {
 	return fd;
 }
 
-/* TODO: make the function return a `wlr_drm_lease` to provide a destroy event
+struct wlr_drm_lease *wlr_drm_create_lease(struct wlr_output **outputs,
- * that can be fired when the kernel notifies us through uevent that the lease
+		size_t n_outputs, int *lease_fd_ptr) {
- * has been destroyed
- */
-int wlr_drm_create_lease(struct wlr_output **outputs, size_t n_outputs,
-		uint32_t *lessee_id) {
 	assert(outputs);
 
 	if (n_outputs == 0) {
 		wlr_log(WLR_ERROR, "Can't lease 0 outputs");
-		return -1;
+		return NULL;
 	}
 
 	struct wlr_drm_backend *drm =
@@ -1575,11 +1571,11 @@ int wlr_drm_create_lease(struct wlr_output **outputs, size_t n_outputs,
 	for (size_t i = 0; i < n_outputs; ++i) {
 		struct wlr_drm_connector *conn =
 				get_drm_connector_from_output(outputs[i]);
-		assert(conn->lessee_id == 0);
+		assert(conn->lease == NULL);
 
 		if (conn->backend != drm) {
 			wlr_log(WLR_ERROR, "Can't lease output from different backends");
-			return -1;
+			return NULL;
 		}
 
 		objects[n_objects++] = conn->id;
@@ -1587,7 +1583,7 @@ int wlr_drm_create_lease(struct wlr_output **outputs, size_t n_outputs,
 
 		if (!conn->crtc) {
 			wlr_log(WLR_ERROR, "Connector has no CRTC");
-			return -1;
+			return NULL;
 		}
 
 		objects[n_objects++] = conn->crtc->id;
@@ -1604,50 +1600,63 @@ int wlr_drm_create_lease(struct wlr_output **outputs, size_t n_outputs,
 
 	assert(n_objects != 0);
 
-	wlr_log(WLR_DEBUG, "Issuing DRM lease with the %d objects", n_objects);
+	struct wlr_drm_lease *lease = calloc(1, sizeof(*lease));
+	if (lease == NULL) {
+		return NULL;
+	}
+
+	lease->backend = drm;
+	wl_signal_init(&lease->events.destroy);
+
+	wlr_log(WLR_DEBUG, "Issuing DRM lease with %d objects", n_objects);
 	int lease_fd = drmModeCreateLease(drm->fd, objects, n_objects, 0,
-			lessee_id);
+			&lease->lessee_id);
 	if (lease_fd < 0) {
-		return lease_fd;
+		free(lease);
+		return NULL;
 	}
+	*lease_fd_ptr = lease_fd;
 
-	wlr_log(WLR_DEBUG, "Issued DRM lease %"PRIu32, *lessee_id);
+	wlr_log(WLR_DEBUG, "Issued DRM lease %"PRIu32, lease->lessee_id);
 	for (size_t i = 0; i < n_outputs; ++i) {
 		struct wlr_drm_connector *conn =
 				get_drm_connector_from_output(outputs[i]);
-		conn->lessee_id = *lessee_id;
+		conn->lease = lease;
-		conn->crtc->lessee_id = *lessee_id;
+		conn->crtc->lease = lease;
 	}
 
-	return lease_fd;
+	return lease;
 }
 
-bool wlr_drm_backend_terminate_lease(struct wlr_backend *backend,
+void wlr_drm_lease_terminate(struct wlr_drm_lease *lease) {
-		uint32_t lessee_id) {
+	struct wlr_drm_backend *drm = lease->backend;
-	wlr_log(WLR_DEBUG, "Terminating DRM lease %d", lessee_id);
 
-	assert(backend);
+	wlr_log(WLR_DEBUG, "Terminating DRM lease %d", lease->lessee_id);
-	struct wlr_drm_backend *drm = get_drm_backend_from_backend(backend);
+	int ret = drmModeRevokeLease(drm->fd, lease->lessee_id);
-
+	if (ret < 0) {
-	int r = drmModeRevokeLease(drm->fd, lessee_id);
+		wlr_log_errno(WLR_ERROR, "Failed to terminate lease");
-	if (r < 0) {
-		wlr_log_errno(WLR_DEBUG, "Failed to terminate lease");
 	}
 
+	drm_lease_destroy(lease);
+}
+
+void drm_lease_destroy(struct wlr_drm_lease *lease) {
+	struct wlr_drm_backend *drm = lease->backend;
+
+	wlr_signal_emit_safe(&lease->events.destroy, NULL);
+
 	struct wlr_drm_connector *conn;
 	wl_list_for_each(conn, &drm->outputs, link) {
-		if (conn->lessee_id == lessee_id) {
+		if (conn->lease == lease) {
-			conn->lessee_id = 0;
+			conn->lease = NULL;
-			/* Will be re-initialized in scan_drm_connectors */
 		}
 	}
 
 	for (size_t i = 0; i < drm->num_crtcs; ++i) {
-		if (drm->crtcs[i].lessee_id == lessee_id) {
+		if (drm->crtcs[i].lease == lease) {
-			drm->crtcs[i].lessee_id = 0;
+			drm->crtcs[i].lease = NULL;
 		}
 	}
 
-	return r >= 0;
+	free(lease);
 }
-

include/backend/drm/drm.h

@@ -36,7 +36,7 @@ struct wlr_drm_plane {
 
 struct wlr_drm_crtc {
 	uint32_t id;
-	uint32_t lessee_id;
+	struct wlr_drm_lease *lease;
 
 	// Atomic modesetting only
 	uint32_t mode_id;
@@ -118,7 +118,7 @@ struct wlr_drm_connector {
 	enum wlr_drm_connector_status status;
 	bool desired_enabled;
 	uint32_t id;
-	uint32_t lessee_id;
+	struct wlr_drm_lease *lease;
 
 	struct wlr_drm_crtc *crtc;
 	uint32_t possible_crtcs;
@@ -157,6 +157,7 @@ bool drm_connector_is_cursor_visible(struct wlr_drm_connector *conn);
 bool drm_connector_supports_vrr(struct wlr_drm_connector *conn);
 size_t drm_crtc_get_gamma_lut_size(struct wlr_drm_backend *drm,
 	struct wlr_drm_crtc *crtc);
+void drm_lease_destroy(struct wlr_drm_lease *lease);
 
 struct wlr_drm_fb *plane_get_next_fb(struct wlr_drm_plane *plane);
 

include/wlr/backend/drm.h

@@ -14,6 +14,20 @@
 #include <wlr/backend/session.h>
 #include <wlr/types/wlr_output.h>
 
+struct wlr_drm_backend;
+
+struct wlr_drm_lease {
+	int fd;
+	uint32_t lessee_id;
+	struct wlr_drm_backend *backend;
+
+	struct {
+		struct wl_signal destroy;
+	} events;
+
+	void *data;
+};
+
 /**
  * Creates a DRM backend using the specified GPU file descriptor (typically from
  * a device node in /dev/dri).
@@ -41,18 +55,20 @@ uint32_t wlr_drm_connector_get_id(struct wlr_output *output);
 int wlr_drm_backend_get_non_master_fd(struct wlr_backend *backend);
 
 /**
- * Leases a given output to the caller. The output must be from the associated
+ * Leases the given outputs to the caller. The outputs must be from the
- * DRM backend.
+ * associated DRM backend.
- * Returns a valid opened DRM FD or -1 on error.
+ *
+ * Returns NULL on error.
  */
-int wlr_drm_create_lease(struct wlr_output **outputs, size_t n_outputs,
+struct wlr_drm_lease *wlr_drm_create_lease(struct wlr_output **outputs,
-		uint32_t *lessee_id);
+	size_t n_outputs, int *lease_fd);
 
 /**
- * Terminates a given lease. The output will be owned again by the backend
+ * Terminates and destroys a given lease.
+ *
+ * The outputs will be owned again by the backend.
  */
-bool wlr_drm_backend_terminate_lease(struct wlr_backend *backend,
+void wlr_drm_lease_terminate(struct wlr_drm_lease *lease);
-	uint32_t lessee_id);
 
 /**
  * Add mode to the list of available modes

include/wlr/types/wlr_drm_lease_v1.h

@@ -81,14 +81,13 @@ struct wlr_drm_lease_request_v1 {
 
 struct wlr_drm_lease_v1 {
 	struct wl_resource *resource;
+	struct wlr_drm_lease *drm_lease;
 
 	struct wlr_drm_lease_device_v1 *device;
 
 	struct wlr_drm_lease_connector_v1 **connectors;
 	size_t n_connectors;
 
-	uint32_t lessee_id;
-
 	struct wl_list link; // wlr_drm_lease_device_v1::leases
 
 	void *data;

types/wlr_drm_lease_v1.c

@@ -52,13 +52,11 @@ static void drm_lease_v1_destroy(struct wlr_drm_lease_v1 *lease) {
 		return;
 	}
 
-	wlr_log(WLR_DEBUG, "Destroying lease %"PRIu32, lease->lessee_id);
+	wlr_log(WLR_DEBUG, "Destroying lease %"PRIu32, lease->drm_lease->lessee_id);
 
 	wp_drm_lease_v1_send_finished(lease->resource);
 
-	struct wlr_drm_lease_device_v1 *device = lease->device;
+	wlr_drm_lease_terminate(lease->drm_lease);
-	wlr_drm_backend_terminate_lease(device->backend, lease->lessee_id);
-	lease->lessee_id = 0;
 
 	for (size_t i = 0; i < lease->n_connectors; ++i) {
 		lease->connectors[i]->active_lease = NULL;
@@ -171,10 +169,10 @@ struct wlr_drm_lease_v1 *wlr_drm_lease_request_v1_grant(
 		outputs[i] = request->connectors[i]->output;
 	}
 
-	int fd = wlr_drm_create_lease(outputs, request->n_connectors,
+	int fd;
-			&lease->lessee_id);
+	lease->drm_lease = wlr_drm_create_lease(outputs, request->n_connectors, &fd);
-	if (fd < 0) {
+	if (!lease->drm_lease) {
-		wlr_log_errno(WLR_ERROR, "drm_create_lease failed");
+		wlr_log(WLR_ERROR, "wlr_drm_create_lease failed");
 		wp_drm_lease_v1_send_finished(lease->resource);
 		return NULL;
 	}
@@ -183,6 +181,7 @@ struct wlr_drm_lease_v1 *wlr_drm_lease_request_v1_grant(
 			sizeof(struct wlr_drm_lease_connector_v1 *));
 	if (!lease->connectors) {
 		wlr_log(WLR_ERROR, "Failed to allocate lease connectors list");
+		close(fd);
 		wp_drm_lease_v1_send_finished(lease->resource);
 		return NULL;
 	}
@@ -212,7 +211,7 @@ void wlr_drm_lease_request_v1_reject(
 
 void wlr_drm_lease_v1_revoke(struct wlr_drm_lease_v1 *lease) {
 	assert(lease);
-	wlr_log(WLR_DEBUG, "Revoking lease %"PRIu32, lease->lessee_id);
+	wlr_log(WLR_DEBUG, "Revoking lease %"PRIu32, lease->drm_lease->lessee_id);
 
 	drm_lease_v1_destroy(lease);
 }