linux-kernel - [PATCH] drm: Fix wrong use of connector in vop_get_edp

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Date:   Sun, 24 Oct 2021 21:55:50 -0400
From:   He Ying <heying24@...wei.com>
To:     <hjc@...k-chips.com>, <heiko@...ech.de>, <airlied@...ux.ie>,
        <daniel@...ll.ch>, <seanpaul@...omium.org>,
        <gustavo.padovan@...labora.com>
CC:     <dri-devel@...ts.freedesktop.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-rockchip@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm: Fix wrong use of connector in vop_get_edp_connector

>From the comments of drm_for_each_connector_iter(), we know
that "connector is only valid within the list body, if you
want to use connector after calling drm_connector_list_iter_end()
then you need to grab your own reference first using
drm_connector_get()". So fix the wrong use of connector
according to the comments and then call drm_connector_put()
after using connector finishes.

Signed-off-by: He Ying <heying24@...wei.com>
Fixes: 2cbeb64f6c70 ("drm/rockchip: use drm_for_each_connector_iter()")
---
 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index a25b98b7f5bd..469922ad29fa 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1581,19 +1581,19 @@ static void vop_crtc_reset(struct drm_crtc *crtc)
 #ifdef CONFIG_DRM_ANALOGIX_DP
 static struct drm_connector *vop_get_edp_connector(struct vop *vop)
 {
-	struct drm_connector *connector;
+	struct drm_connector *connector = NULL;
 	struct drm_connector_list_iter conn_iter;
 
 	drm_connector_list_iter_begin(vop->drm_dev, &conn_iter);
 	drm_for_each_connector_iter(connector, &conn_iter) {
 		if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
-			drm_connector_list_iter_end(&conn_iter);
-			return connector;
+			drm_connector_get(connector);
+			break;
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);
 
-	return NULL;
+	return connector;
 }
 
 static int vop_crtc_set_crc_source(struct drm_crtc *crtc,
@@ -1614,6 +1614,7 @@ static int vop_crtc_set_crc_source(struct drm_crtc *crtc,
 	else
 		ret = -EINVAL;
 
+	drm_connector_put(connector);
 	return ret;
 }
 
-- 
2.17.1