Instead of using dsi->out_bridge during the bridge search process, use a
temporary variable and assign dsi->out_bridge only on successful
completion.
The main goal is to be able to drm_bridge_get() the out_bridge before
setting it in dsi->out_bridge, which is done in a later commit. Setting
dsi->out_bridge as in current code would leave a use-after-free window in
case the bridge is deallocated by some other thread between
'dsi->out_bridge = devm_drm_panel_bridge_add()' and drm_bridge_get().
This change additionally avoids leaving an ERR_PTR value in dsi->out_bridge
on failure. This is not necessarily a problem but it is not clean.
Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
---
This patch was added in v5.
---
drivers/gpu/drm/bridge/samsung-dsim.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index f8b4fb8357659018ec0db65374ee5d05330639ae..c4d1563fd32019efde523dfc0863be044c05a826 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1705,6 +1705,7 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
struct device *dev = dsi->dev;
struct device_node *np = dev->of_node;
struct device_node *remote;
+ struct drm_bridge *out_bridge;
struct drm_panel *panel;
int ret;
@@ -1740,21 +1741,23 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
panel = of_drm_find_panel(remote);
if (!IS_ERR(panel)) {
- dsi->out_bridge = devm_drm_panel_bridge_add(dev, panel);
+ out_bridge = devm_drm_panel_bridge_add(dev, panel);
} else {
- dsi->out_bridge = of_drm_find_bridge(remote);
- if (!dsi->out_bridge)
- dsi->out_bridge = ERR_PTR(-EINVAL);
+ out_bridge = of_drm_find_bridge(remote);
+ if (!out_bridge)
+ out_bridge = ERR_PTR(-EINVAL);
}
of_node_put(remote);
- if (IS_ERR(dsi->out_bridge)) {
- ret = PTR_ERR(dsi->out_bridge);
+ if (IS_ERR(out_bridge)) {
+ ret = PTR_ERR(out_bridge);
DRM_DEV_ERROR(dev, "failed to find the bridge: %d\n", ret);
return ret;
}
+ dsi->out_bridge = out_bridge;
+
DRM_DEV_INFO(dev, "Attached %s device (lanes:%d bpp:%d mode-flags:0x%lx)\n",
device->name, device->lanes,
mipi_dsi_pixel_format_to_bpp(device->format),
--
2.34.1
