From: Ville Syrjälä ville.syrjala@linux.intel.com
struct drm_display_mode embeds a list head, so overwriting the full struct with another one will corrupt the list (if the destination mode is on a list). Use drm_mode_copy() instead which explicitly preserves the list head of the destination mode.
Even if we know the destination mode is not on any list using drm_mode_copy() seems decent as it sets a good example. Bad examples of not using it might eventually get copied into code where preserving the list head actually matters.
Obviously one case not covered here is when the mode itself is embedded in a larger structure and the whole structure is copied. But if we are careful when copying into modes embedded in structures I think we can be a little more reassured that bogus list heads haven't been propagated in.
@is_mode_copy@ @@ drm_mode_copy(...) { ... }
@depends on !is_mode_copy@ struct drm_display_mode *mode; expression E, S; @@ ( - *mode = E + drm_mode_copy(mode, &E) | - memcpy(mode, E, S) + drm_mode_copy(mode, E) )
@depends on !is_mode_copy@ struct drm_display_mode mode; expression E; @@ ( - mode = E + drm_mode_copy(&mode, &E) | - memcpy(&mode, E, S) + drm_mode_copy(&mode, E) )
@@ struct drm_display_mode *mode; @@ - &*mode + mode
Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Sandy Huang hjc@rock-chips.com Cc: "Heiko Stübner" heiko@sntech.de Cc: linux-arm-kernel@lists.infradead.org Cc: linux-rockchip@lists.infradead.org --- drivers/gpu/drm/rockchip/cdn-dp-core.c | 2 +- drivers/gpu/drm/rockchip/inno_hdmi.c | 2 +- drivers/gpu/drm/rockchip/rk3066_hdmi.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c index 4740cc14beb8..adf1027a3f20 100644 --- a/drivers/gpu/drm/rockchip/cdn-dp-core.c +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c @@ -564,7 +564,7 @@ static void cdn_dp_encoder_mode_set(struct drm_encoder *encoder, video->v_sync_polarity = !!(mode->flags & DRM_MODE_FLAG_NVSYNC); video->h_sync_polarity = !!(mode->flags & DRM_MODE_FLAG_NHSYNC);
- memcpy(&dp->mode, adjusted, sizeof(*mode)); + drm_mode_copy(&dp->mode, adjusted); }
static bool cdn_dp_check_link_status(struct cdn_dp_device *dp) diff --git a/drivers/gpu/drm/rockchip/inno_hdmi.c b/drivers/gpu/drm/rockchip/inno_hdmi.c index 046e8ec2a71c..740196d30fba 100644 --- a/drivers/gpu/drm/rockchip/inno_hdmi.c +++ b/drivers/gpu/drm/rockchip/inno_hdmi.c @@ -488,7 +488,7 @@ static void inno_hdmi_encoder_mode_set(struct drm_encoder *encoder, inno_hdmi_setup(hdmi, adj_mode);
/* Store the display mode for plugin/DPMS poweron events */ - memcpy(&hdmi->previous_mode, adj_mode, sizeof(hdmi->previous_mode)); + drm_mode_copy(&hdmi->previous_mode, adj_mode); }
static void inno_hdmi_encoder_enable(struct drm_encoder *encoder) diff --git a/drivers/gpu/drm/rockchip/rk3066_hdmi.c b/drivers/gpu/drm/rockchip/rk3066_hdmi.c index 1c546c3a8998..17e7c40a9e7b 100644 --- a/drivers/gpu/drm/rockchip/rk3066_hdmi.c +++ b/drivers/gpu/drm/rockchip/rk3066_hdmi.c @@ -383,7 +383,7 @@ rk3066_hdmi_encoder_mode_set(struct drm_encoder *encoder, struct rk3066_hdmi *hdmi = to_rk3066_hdmi(encoder);
/* Store the display mode for plugin/DPMS poweron events. */ - memcpy(&hdmi->previous_mode, adj_mode, sizeof(hdmi->previous_mode)); + drm_mode_copy(&hdmi->previous_mode, adj_mode); }
static void rk3066_hdmi_encoder_enable(struct drm_encoder *encoder)