linux-kernel - [PATCH 4/4] drm/vmwgfx: unwind spaghetti code in vmw_dma_select

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Date:   Sat,  5 Jan 2019 09:01:08 +0100
From:   Christoph Hellwig <hch@....de>
To:     thellstrom@...are.com
Cc:     linux-graphics-maintainer@...are.com,
        dri-devel@...ts.freedesktop.org, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 4/4] drm/vmwgfx: unwind spaghetti code in vmw_dma_select_mode

Just use a simple if/else chain to select the DMA mode.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 25 ++++++-------------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index c2060f6cc9e8..86387735a90b 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -566,34 +566,21 @@ static int vmw_dma_select_mode(struct vmw_private *dev_priv)
 		[vmw_dma_map_populate] = "Keeping DMA mappings.",
 		[vmw_dma_map_bind] = "Giving up DMA mappings early."};
 
-	if (intel_iommu_enabled) {
+	if (vmw_force_coherent)
+		dev_priv->map_mode = vmw_dma_alloc_coherent;
+	else if (intel_iommu_enabled)
 		dev_priv->map_mode = vmw_dma_map_populate;
-		goto out_fixup;
-	}
-
-	if (!(vmw_force_iommu || vmw_force_coherent)) {
+	else if (!vmw_force_iommu)
 		dev_priv->map_mode = vmw_dma_phys;
-		DRM_INFO("DMA map mode: %s\n", names[dev_priv->map_mode]);
-		return 0;
-	}
-
-#ifdef CONFIG_SWIOTLB
-	if (swiotlb_nr_tbl())
+	else if (IS_ENABLED(CONFIG_SWIOTLB) && swiotlb_nr_tbl())
 		dev_priv->map_mode = vmw_dma_alloc_coherent;
 	else
-#endif
 		dev_priv->map_mode = vmw_dma_map_populate;
 
-out_fixup:
-	if (dev_priv->map_mode == vmw_dma_map_populate &&
-	    vmw_restrict_iommu)
+	if (dev_priv->map_mode == vmw_dma_map_populate && vmw_restrict_iommu)
 		dev_priv->map_mode = vmw_dma_map_bind;
 
-	if (vmw_force_coherent)
-		dev_priv->map_mode = vmw_dma_alloc_coherent;
-
 	DRM_INFO("DMA map mode: %s\n", names[dev_priv->map_mode]);
-
 	return 0;
 }
 
-- 
2.20.1