drm/vc4: hdmi: Fix pointer dereference before check

Commit 6bed2ea3cb38 ("drm/vc4: hdmi: Reset link on hotplug") introduced
the vc4_hdmi_reset_link() function. This function dereferences the
"connector" pointer before checking whether it is NULL or not.

Rework variable assignment to avoid this issue.

Fixes: 6bed2ea3cb38 ("drm/vc4: hdmi: Reset link on hotplug")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: https://lore.kernel.org/r/20221110134752.238820-3-jose.exposito89@gmail.com
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index a49f88e..6b223a5 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -318,8 +318,8 @@ out:
 static int vc4_hdmi_reset_link(struct drm_connector *connector,
                               struct drm_modeset_acquire_ctx *ctx)
 {
-       struct drm_device *drm = connector->dev;
-       struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
+       struct drm_device *drm;
+       struct vc4_hdmi *vc4_hdmi;
        struct drm_connector_state *conn_state;
        struct drm_crtc_state *crtc_state;
        struct drm_crtc *crtc;
@@ -330,6 +330,7 @@ static int vc4_hdmi_reset_link(struct drm_connector *connector,
        if (!connector)
                return 0;
 
+       drm = connector->dev;
        ret = drm_modeset_lock(&drm->mode_config.connection_mutex, ctx);
        if (ret)
                return ret;
@@ -347,6 +348,7 @@ static int vc4_hdmi_reset_link(struct drm_connector *connector,
        if (!crtc_state->active)
                return 0;
 
+       vc4_hdmi = connector_to_vc4_hdmi(connector);
        if (!vc4_hdmi_supports_scrambling(vc4_hdmi))
                return 0;