From: Magnus Damm <[email protected]> Introduce the flag "no_size_align" to allow disabling size-alignment on a per-domain basis. This follows the suggestion by the comment in the code, however a per-device control may be preferred?
Needed to make virtual space contiguous for certain devices. Signed-off-by: Magnus Damm <[email protected]> --- drivers/iommu/dma-iommu.c | 6 +++++- include/linux/iommu.h | 1 + 2 files changed, 6 insertions(+), 1 deletion(-) --- 0001/drivers/iommu/dma-iommu.c +++ work/drivers/iommu/dma-iommu.c 2017-01-27 15:17:50.280607110 +0900 @@ -209,14 +209,18 @@ static struct iova *__alloc_iova(struct struct iova_domain *iovad = cookie_iovad(domain); unsigned long shift = iova_shift(iovad); unsigned long length = iova_align(iovad, size) >> shift; + bool size_aligned = true; if (domain->geometry.force_aperture) dma_limit = min(dma_limit, domain->geometry.aperture_end); + + if (domain->no_size_align) + size_aligned = false; /* * Enforce size-alignment to be safe - there could perhaps be an * attribute to control this per-device, or at least per-domain... */ - return alloc_iova(iovad, length, dma_limit >> shift, true); + return alloc_iova(iovad, length, dma_limit >> shift, size_aligned); } /* The IOVA allocator knows what we mapped, so just unmap whatever that was */ --- 0001/include/linux/iommu.h +++ work/include/linux/iommu.h 2017-01-27 15:16:37.630607110 +0900 @@ -83,6 +83,7 @@ struct iommu_domain { iommu_fault_handler_t handler; void *handler_token; struct iommu_domain_geometry geometry; + bool no_size_align; void *iova_cookie; };
