Commit a0f8cbce authored by Joe Jin's avatar Joe Jin Committed by Greg Kroah-Hartman

xen-swiotlb: fix the check condition for xen_swiotlb_free_coherent

commit 4855c92d upstream.

When run raidconfig from Dom0 we found that the Xen DMA heap is reduced,
but Dom Heap is increased by the same size. Tracing raidconfig we found
that the related ioctl() in megaraid_sas will call dma_alloc_coherent()
to apply memory. If the memory allocated by Dom0 is not in the DMA area,
it will exchange memory with Xen to meet the requiment. Later drivers
call dma_free_coherent() to free the memory, on xen_swiotlb_free_coherent()
the check condition (dev_addr + size - 1 <= dma_mask) is always false,
it prevents calling xen_destroy_contiguous_region() to return the memory
to the Xen DMA heap.

This issue introduced by commit 6810df88 "xen-swiotlb: When doing
coherent alloc/dealloc check before swizzling the MFNs.".
Signed-off-by: default avatarJoe Jin <>
Tested-by: default avatarJohn Sobecki <>
Reviewed-by: default avatarRzeszutek Wilk <>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 4182f5a0
......@@ -365,7 +365,7 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
* physical address */
phys = xen_bus_to_phys(dev_addr);
if (((dev_addr + size - 1 > dma_mask)) ||
if (((dev_addr + size - 1 <= dma_mask)) ||
range_straddles_page_boundary(phys, size))
xen_destroy_contiguous_region(phys, order);
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