drm/i915/dsb: fix cmd_buf being wrongly set

The "err" label is not really "err", but rather "out" since the return
path is shared between error condition and normal path. This broke when
commit 03cea610 ("drm/i915/dsb: fix extra warning on error path
handling") added a "dsb->cmd_buf = NULL;" there, making DSB to stop
working since now all writes would pass-through via mmio.

Remove the set to NULL since it's actually not needed: we only set it if
all steps are successful. While at it, rename the label so this confusion
doesn't happen again.

Fixes: 03cea610 ("drm/i915/dsb: fix extra warning on error path handling")
Resolves: https://gitlab.freedesktop.org/drm/intel/issues/8Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NAnimesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191127221119.384754-1-lucas.demarchi@intel.com

drivers/gpu/drm/i915/display/intel_dsb.c

@@ -116,34 +116,34 @@ intel_dsb_get(struct intel_crtc *crtc)
 	obj = i915_gem_object_create_internal(i915, DSB_BUF_SIZE);
 	if (IS_ERR(obj)) {
 		DRM_ERROR("Gem object creation failed\n");
-		goto err;
+		goto out;
 	}
 
 	vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, 0);
 	if (IS_ERR(vma)) {
 		DRM_ERROR("Vma creation failed\n");
 		i915_gem_object_put(obj);
-		goto err;
+		goto out;
 	}
 
 	buf = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
 	if (IS_ERR(buf)) {
 		DRM_ERROR("Command buffer creation failed\n");
-		goto err;
+		goto out;
 	}
 
 	dsb->id = DSB1;
 	dsb->vma = vma;
 	dsb->cmd_buf = buf;
 
-err:
+out:
 	/*
-	 * Set cmd_buf to NULL so the writes pass-through, but leave the
-	 * dangling refcount to be removed later by the corresponding
-	 * intel_dsb_put(): the important error message will already be
-	 * logged above.
+	 * On error dsb->cmd_buf will continue to be NULL, making the writes
+	 * pass-through. Leave the dangling ref to be removed later by the
+	 * corresponding intel_dsb_put(): the important error message will
+	 * already be logged above.
 	 */
-	dsb->cmd_buf = NULL;
+
 	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
 
 	return dsb;