drm/v3d: Use drmm_add_final_kfree

With this we can drop the final kfree from the release function.

I also noticed that the unwind code is wrong, after drm_dev_init the
drm_device owns the v3d allocation, so the kfree(v3d) is a double-free.
Reorder the setup to fix this issue.

After a bit more prep in drivers and drm core v3d should be able to
switch over to devm_drm_dev_init, which should clean this up further.
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-11-daniel.vetter@ffwll.ch

drivers/gpu/drm/v3d/v3d_drv.c

@@ -25,6 +25,7 @@
 #include <drm/drm_drv.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_fb_helper.h>
+#include <drm/drm_managed.h>
 #include <uapi/drm/v3d_drm.h>
 
 #include "v3d_drv.h"
@@ -257,13 +258,23 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
 	v3d->pdev = pdev;
 	drm = &v3d->drm;
 
+	ret = drm_dev_init(&v3d->drm, &v3d_drm_driver, dev);
+	if (ret) {
+		kfree(v3d);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, drm);
+	drm->dev_private = v3d;
+	drmm_add_final_kfree(drm, v3d);
+
 	ret = map_regs(v3d, &v3d->hub_regs, "hub");
 	if (ret)
-		goto dev_free;
+		goto dev_destroy;
 
 	ret = map_regs(v3d, &v3d->core_regs[0], "core0");
 	if (ret)
-		goto dev_free;
+		goto dev_destroy;
 
 	mmu_debug = V3D_READ(V3D_MMU_DEBUG_INFO);
 	dev->coherent_dma_mask =
@@ -281,21 +292,21 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
 		ret = PTR_ERR(v3d->reset);
 
 		if (ret == -EPROBE_DEFER)
-			goto dev_free;
+			goto dev_destroy;
 
 		v3d->reset = NULL;
 		ret = map_regs(v3d, &v3d->bridge_regs, "bridge");
 		if (ret) {
 			dev_err(dev,
 				"Failed to get reset control or bridge regs\n");
-			goto dev_free;
+			goto dev_destroy;
 		}
 	}
 
 	if (v3d->ver < 41) {
 		ret = map_regs(v3d, &v3d->gca_regs, "gca");
 		if (ret)
-			goto dev_free;
+			goto dev_destroy;
 	}
 
 	v3d->mmu_scratch = dma_alloc_wc(dev, 4096, &v3d->mmu_scratch_paddr,
@@ -303,23 +314,16 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
 	if (!v3d->mmu_scratch) {
 		dev_err(dev, "Failed to allocate MMU scratch page\n");
 		ret = -ENOMEM;
-		goto dev_free;
+		goto dev_destroy;
 	}
 
 	pm_runtime_use_autosuspend(dev);
 	pm_runtime_set_autosuspend_delay(dev, 50);
 	pm_runtime_enable(dev);
 
-	ret = drm_dev_init(&v3d->drm, &v3d_drm_driver, dev);
-	if (ret)
-		goto dma_free;
-
-	platform_set_drvdata(pdev, drm);
-	drm->dev_private = v3d;
-
 	ret = v3d_gem_init(drm);
 	if (ret)
-		goto dev_destroy;
+		goto dma_free;
 
 	ret = v3d_irq_init(v3d);
 	if (ret)
@@ -335,12 +339,10 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
 	v3d_irq_disable(v3d);
 gem_destroy:
 	v3d_gem_destroy(drm);
-dev_destroy:
-	drm_dev_put(drm);
 dma_free:
 	dma_free_wc(dev, 4096, v3d->mmu_scratch, v3d->mmu_scratch_paddr);
-dev_free:
-	kfree(v3d);
+dev_destroy:
+	drm_dev_put(drm);
 	return ret;
 }