[PATCH drm-misc-next 1/7] drm/arm/hdlcd: use drmm_* to allocate driver structures

From: Danilo Krummrich
Date: Fri Aug 19 2022 - 19:11:16 EST


Use drm managed resources to allocate driver structures and get rid of
the deprecated drm_dev_alloc() call and replace it with
devm_drm_dev_alloc().

This also serves as preparation to get rid of drm_device->dev_private
and to fix use-after-free issues on driver unload.

Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
---
drivers/gpu/drm/arm/hdlcd_drv.c | 12 ++++--------
drivers/gpu/drm/arm/hdlcd_drv.h | 1 +
2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
index a032003c340c..463381d11cff 100644
--- a/drivers/gpu/drm/arm/hdlcd_drv.c
+++ b/drivers/gpu/drm/arm/hdlcd_drv.c
@@ -247,13 +247,11 @@ static int hdlcd_drm_bind(struct device *dev)
struct hdlcd_drm_private *hdlcd;
int ret;

- hdlcd = devm_kzalloc(dev, sizeof(*hdlcd), GFP_KERNEL);
- if (!hdlcd)
- return -ENOMEM;
+ hdlcd = devm_drm_dev_alloc(dev, &hdlcd_driver, typeof(*hdlcd), base);
+ if (IS_ERR(hdlcd))
+ return PTR_ERR(hdlcd);

- drm = drm_dev_alloc(&hdlcd_driver, dev);
- if (IS_ERR(drm))
- return PTR_ERR(drm);
+ drm = &hdlcd->base;

drm->dev_private = hdlcd;
dev_set_drvdata(dev, drm);
@@ -319,7 +317,6 @@ static int hdlcd_drm_bind(struct device *dev)
err_free:
drm_mode_config_cleanup(drm);
dev_set_drvdata(dev, NULL);
- drm_dev_put(drm);

return ret;
}
@@ -344,7 +341,6 @@ static void hdlcd_drm_unbind(struct device *dev)
drm_mode_config_cleanup(drm);
drm->dev_private = NULL;
dev_set_drvdata(dev, NULL);
- drm_dev_put(drm);
}

static const struct component_master_ops hdlcd_master_ops = {
diff --git a/drivers/gpu/drm/arm/hdlcd_drv.h b/drivers/gpu/drm/arm/hdlcd_drv.h
index 909c39c28487..3892b36767ac 100644
--- a/drivers/gpu/drm/arm/hdlcd_drv.h
+++ b/drivers/gpu/drm/arm/hdlcd_drv.h
@@ -7,6 +7,7 @@
#define __HDLCD_DRV_H__

struct hdlcd_drm_private {
+ struct drm_device base;
void __iomem *mmio;
struct clk *clk;
struct drm_crtc crtc;
--
2.37.2