Thread (25 messages) 25 messages, 2 authors, 2021-05-18

Re: [PATCH v6 08/15] swiotlb: Bounce data from/to restricted DMA pool if available

From: Christoph Hellwig <hch@lst.de>
Date: 2021-05-10 15:06:57
Also in: intel-gfx, linux-devicetree, linux-iommu, linux-pci, lkml, nouveau, xen-devel

+static inline bool is_dev_swiotlb_force(struct device *dev)
+{
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (dev->dma_io_tlb_mem)
+		return true;
+#endif /* CONFIG_DMA_RESTRICTED_POOL */
+	return false;
+}
+
 	/* If SWIOTLB is active, use its maximum mapping size */
 	if (is_swiotlb_active(dev) &&
-	    (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE))
+	    (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE ||
+	     is_dev_swiotlb_force(dev)))
This is a mess.  I think the right way is to have an always_bounce flag
in the io_tlb_mem structure instead.  Then the global swiotlb_force can
go away and be replace with this and the fact that having no
io_tlb_mem structure at all means forced no buffering (after a little
refactoring).
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