[PATCH] drm: Grab reference of connector before return connector from sun4i_tcon_get_connector

[He Ying]

>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 <heyin...@huawei.com>
---
 drivers/gpu/drm/sun4i/sun4i_tcon.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c 
b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 9f06dec0fc61..24fa6784ee5f 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -47,12 +47,12 @@ static struct drm_connector *sun4i_tcon_get_connector(const 
struct drm_encoder *
        drm_connector_list_iter_begin(encoder->dev, &iter);
        drm_for_each_connector_iter(connector, &iter)
                if (connector->encoder == encoder) {
-                       drm_connector_list_iter_end(&iter);
-                       return connector;
+                       drm_connector_get(connector);
+                       break;
                }
        drm_connector_list_iter_end(&iter);
 
-       return NULL;
+       return connector;
 }
 
 static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
@@ -65,6 +65,7 @@ static int sun4i_tcon_get_pixel_depth(const struct 
drm_encoder *encoder)
                return -EINVAL;
 
        info = &connector->display_info;
+       drm_connector_put(connector);
        if (info->num_bus_formats != 1)
                return -EINVAL;
 
@@ -361,6 +362,7 @@ static void sun4i_tcon0_mode_set_cpu(struct sun4i_tcon 
*tcon,
        /* TODO support normal CPU interface modes */
        struct sun6i_dsi *dsi = encoder_to_sun6i_dsi(encoder);
        struct mipi_dsi_device *device = dsi->device;
+       struct drm_connector *connector;
        u8 bpp = mipi_dsi_pixel_format_to_bpp(device->format);
        u8 lanes = device->lanes;
        u32 block_space, start_delay;
@@ -372,7 +374,9 @@ static void sun4i_tcon0_mode_set_cpu(struct sun4i_tcon 
*tcon,
        sun4i_tcon0_mode_set_common(tcon, mode);
 
        /* Set dithering if needed */
-       sun4i_tcon0_mode_set_dithering(tcon, sun4i_tcon_get_connector(encoder));
+       connector = sun4i_tcon_get_connector(encoder);
+       sun4i_tcon0_mode_set_dithering(tcon, connector);
+       drm_connector_put(connector);
 
        regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
                           SUN4I_TCON0_CTL_IF_MASK,
@@ -430,6 +434,7 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon 
*tcon,
                                      const struct drm_display_mode *mode)
 {
        unsigned int bp;
+       struct drm_connector *connector;
        u8 clk_delay;
        u32 reg, val = 0;
 
@@ -440,7 +445,9 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon 
*tcon,
        sun4i_tcon0_mode_set_common(tcon, mode);
 
        /* Set dithering if needed */
-       sun4i_tcon0_mode_set_dithering(tcon, sun4i_tcon_get_connector(encoder));
+       connector = sun4i_tcon_get_connector(encoder);
+       sun4i_tcon0_mode_set_dithering(tcon, connector);
+       drm_connector_put(connector);
 
        /* Adjust clock delay */
        clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
@@ -518,6 +525,7 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon 
*tcon,
 
        /* Set dithering if needed */
        sun4i_tcon0_mode_set_dithering(tcon, connector);
+       drm_connector_put(connector);
 
        /* Adjust clock delay */
        clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
-- 
2.17.1