[patch] drm/tegra: fixup error handling in tegra_dc_init()

[Dan Carpenter]

1)  There was a chance that "cursor" or "primary" were error pointers
    leading to an oops.
2)  The error handling wasn't very complete.

When I started working on this, the one err label style error handling
became unwieldy so I just re-wrote it with multiple exit labels.

Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
---
Compile tested only.

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index fb2b4b0..8134e30 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -1683,8 +1683,8 @@ static int tegra_dc_init(struct host1x_client *client)
        unsigned long flags = HOST1X_SYNCPT_CLIENT_MANAGED;
        struct tegra_dc *dc = host1x_client_to_dc(client);
        struct tegra_drm *tegra = drm->dev_private;
-       struct drm_plane *primary = NULL;
-       struct drm_plane *cursor = NULL;
+       struct drm_plane *primary;
+       struct drm_plane *cursor;
        u32 value;
        int err;

@@ -1706,21 +1706,22 @@ static int tegra_dc_init(struct host1x_client *client)
        primary = tegra_dc_primary_plane_create(drm, dc);
        if (IS_ERR(primary)) {
                err = PTR_ERR(primary);
-               goto cleanup;
+               goto detach_iommu;
        }

+       cursor = NULL;
        if (dc->soc->supports_cursor) {
                cursor = tegra_dc_cursor_plane_create(drm, dc);
                if (IS_ERR(cursor)) {
                        err = PTR_ERR(cursor);
-                       goto cleanup;
+                       goto cleanup_primary;
                }
        }

        err = drm_crtc_init_with_planes(drm, &dc->base, primary, cursor,
                                        &tegra_crtc_funcs, NULL);
        if (err < 0)
-               goto cleanup;
+               goto cleanup_cursor;

        drm_mode_crtc_set_gamma_size(&dc->base, 256);
        drm_crtc_helper_add(&dc->base, &tegra_crtc_helper_funcs);
@@ -1735,12 +1736,12 @@ static int tegra_dc_init(struct host1x_client *client)
        err = tegra_dc_rgb_init(drm, dc);
        if (err < 0 && err != -ENODEV) {
                dev_err(dc->dev, "failed to initialize RGB output: %d\n", err);
-               goto cleanup;
+               goto cleanup_cursor;
        }

        err = tegra_dc_add_planes(drm, dc);
        if (err < 0)
-               goto cleanup;
+               goto rgb_exit;

        if (IS_ENABLED(CONFIG_DEBUG_FS)) {
                err = tegra_dc_debugfs_init(dc, drm->primary);
@@ -1753,7 +1754,7 @@ static int tegra_dc_init(struct host1x_client *client)
        if (err < 0) {
                dev_err(dc->dev, "failed to request IRQ#%u: %d\n", dc->irq,
                        err);
-               goto cleanup;
+               goto remove_debugfs;
        }

        /* initialize display controller */
@@ -1799,13 +1800,18 @@ static int tegra_dc_init(struct host1x_client *client)

        return 0;

-cleanup:
-       if (cursor)
+remove_debugfs:
+       tegra_dc_debugfs_exit(dc);
+rgb_exit:
+       tegra_dc_rgb_exit(dc);
+cleanup_cursor:
+       if (dc->soc->supports_cursor)
                drm_plane_cleanup(cursor);

-       if (primary)
-               drm_plane_cleanup(primary);
+cleanup_primary:
+       drm_plane_cleanup(primary);

+detach_iommu:
        if (tegra->domain) {
                iommu_detach_device(tegra->domain, dc->dev);
                dc->domain = NULL;