drm/i915: Cleanup fbdev fb setup

We use a mix of 'intel_fb' vs. 'ifbdev->fb' in the same function.
Both should be pointing at the same thing. Make things less
confusing by just getting existing fb from 'ifbdev->fb' at the
start and then sticking with the local 'fb' (renamed from the
'intel_fb') until the very end.

v2: rebase
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240510102257.25096-1-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -175,7 +175,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 			  struct drm_fb_helper_surface_size *sizes)
 {
 	struct intel_fbdev *ifbdev = to_intel_fbdev(helper);
-	struct intel_framebuffer *intel_fb = ifbdev->fb;
+	struct intel_framebuffer *fb = ifbdev->fb;
 	struct drm_device *dev = helper->dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	const struct i915_gtt_view view = {
@@ -195,29 +195,30 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	if (ret)
 		return ret;
 
-	if (intel_fb &&
-	    (sizes->fb_width > intel_fb->base.width ||
-	     sizes->fb_height > intel_fb->base.height)) {
+	ifbdev->fb = NULL;
+
+	if (fb &&
+	    (sizes->fb_width > fb->base.width ||
+	     sizes->fb_height > fb->base.height)) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "BIOS fb too small (%dx%d), we require (%dx%d),"
 			    " releasing it\n",
-			    intel_fb->base.width, intel_fb->base.height,
+			    fb->base.width, fb->base.height,
 			    sizes->fb_width, sizes->fb_height);
-		drm_framebuffer_put(&intel_fb->base);
-		intel_fb = ifbdev->fb = NULL;
+		drm_framebuffer_put(&fb->base);
+		fb = NULL;
 	}
-	if (!intel_fb || drm_WARN_ON(dev, !intel_fb_obj(&intel_fb->base))) {
+	if (!fb || drm_WARN_ON(dev, !intel_fb_obj(&fb->base))) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "no BIOS fb, allocating a new one\n");
-		intel_fb = intel_fbdev_fb_alloc(helper, sizes);
-		if (IS_ERR(intel_fb))
-			return PTR_ERR(intel_fb);
-		ifbdev->fb = intel_fb;
+		fb = intel_fbdev_fb_alloc(helper, sizes);
+		if (IS_ERR(fb))
+			return PTR_ERR(fb);
 	} else {
 		drm_dbg_kms(&dev_priv->drm, "re-using BIOS fb\n");
 		prealloc = true;
-		sizes->fb_width = intel_fb->base.width;
-		sizes->fb_height = intel_fb->base.height;
+		sizes->fb_width = fb->base.width;
+		sizes->fb_height = fb->base.height;
 	}
 
 	wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
@@ -226,7 +227,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	 * This also validates that any existing fb inherited from the
 	 * BIOS is suitable for own access.
 	 */
-	vma = intel_pin_and_fence_fb_obj(&ifbdev->fb->base, false,
+	vma = intel_pin_and_fence_fb_obj(&fb->base, false,
 					 &view, false, &flags);
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);
@@ -240,11 +241,11 @@ static int intelfb_create(struct drm_fb_helper *helper,
 		goto out_unpin;
 	}
 
-	ifbdev->helper.fb = &ifbdev->fb->base;
+	ifbdev->helper.fb = &fb->base;
 
 	info->fbops = &intelfb_ops;
 
-	obj = intel_fb_obj(&intel_fb->base);
+	obj = intel_fb_obj(&fb->base);
 
 	ret = intel_fbdev_fb_fill_info(dev_priv, info, obj, vma);
 	if (ret)
@@ -262,8 +263,9 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	/* Use default scratch pixmap (info->pixmap.flags = FB_PIXMAP_SYSTEM) */
 
 	drm_dbg_kms(&dev_priv->drm, "allocated %dx%d fb: 0x%08x\n",
-		    ifbdev->fb->base.width, ifbdev->fb->base.height,
+		    fb->base.width, fb->base.height,
 		    i915_ggtt_offset(vma));
+	ifbdev->fb = fb;
 	ifbdev->vma = vma;
 	ifbdev->vma_flags = flags;