powerpc/iommu: return error code from .map_sg() ops

The .map_sg() op now expects an error code instead of zero on failure.

Propagate the error up if vio_dma_iommu_map_sg() fails.

ppc_iommu_map_sg() may fail either because of iommu_range_alloc() or
because of tbl->it_ops->set(). The former only supports returning an
error with DMA_MAPPING_ERROR and an examination of the latter indicates
that it may return arch-specific errors (for example,
tce_buildmulti_pSeriesLP()). Hence, coalesce all of those errors into
-EIO, per the documentation on dma_map_sgtable().

Signed-off-by: Martin Oliveira <martin.oliveira@eideticom.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Geoff Levand <geoff@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 2af89a5e379f..a8ec4fe42817 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -473,7 +473,7 @@ int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
 	BUG_ON(direction == DMA_NONE);
 
 	if ((nelems == 0) || !tbl)
-		return 0;
+		return -EINVAL;
 
 	outs = s = segstart = &sglist[0];
 	outcount = 1;
@@ -599,7 +599,7 @@ int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
 		if (s == outs)
 			break;
 	}
-	return 0;
+	return -EIO;
 }