Commit b9bb694b authored Sep 21, 2020 by Robin Murphy Committed by Christoph Hellwig Sep 21, 2020

iommu/io-pgtable-arm: Clean up faulty sanity check



Checking for a nonzero dma_pfn_offset was a quick shortcut to validate
whether the DMA == phys assumption could hold at all. Checking for a
non-NULL dma_range_map is not quite equivalent, since a map may be
present to describe a limited DMA window even without an offset, and
thus this check can now yield false positives.

However, it only ever served to short-circuit going all the way through
to __arm_lpae_alloc_pages(), failing the canonical test there, and
having a bit more to clean up. As such, we can simply remove it without
loss of correctness.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent a97740f8

drivers/iommu/io-pgtable-arm.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -751,11 +751,6 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
		if (cfg->oas > ARM_LPAE_MAX_ADDR_BITS)
		return NULL;

		if (!selftest_running && cfg->iommu_dev->dma_range_map) {
		dev_err(cfg->iommu_dev, "Cannot accommodate DMA offset for IOMMU page tables\n");
		return NULL;
		}

		data = kmalloc(sizeof(*data), GFP_KERNEL);
		if (!data)
		return NULL;