[PATCH v1 05/16] alpha: return error code from alpha_pci_map_sg()

[Logan Gunthorpe <logang@xxxxxxxxxxxx>]

From: Martin Oliveira <martin.oliveira@xxxxxxxxxxxxx>

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

pci_map_single_1() can fail for different reasons, but since the only
supported type of error return is DMA_MAPPING_ERROR, we coalesce those
errors into EINVAL.

ENOMEM is returned when no page tables can be allocated.

Signed-off-by: Martin Oliveira <martin.oliveira@xxxxxxxxxxxxx>
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
---
 arch/alpha/kernel/pci_iommu.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
index 35d7b3096d6e..72fc2465d13c 100644
--- a/arch/alpha/kernel/pci_iommu.c
+++ b/arch/alpha/kernel/pci_iommu.c
@@ -649,7 +649,9 @@ static int alpha_pci_map_sg(struct device *dev, struct 
scatterlist *sg,
                sg->dma_address
                  = pci_map_single_1(pdev, SG_ENT_VIRT_ADDRESS(sg),
                                     sg->length, dac_allowed);
-               return sg->dma_address != DMA_MAPPING_ERROR;
+               if (sg->dma_address == DMA_MAPPING_ERROR)
+                       return -EINVAL;
+               return 1;
        }
 
        start = sg;
@@ -685,8 +687,10 @@ static int alpha_pci_map_sg(struct device *dev, struct 
scatterlist *sg,
        if (out < end)
                out->dma_length = 0;
 
-       if (out - start == 0)
+       if (out - start == 0) {
                printk(KERN_WARNING "pci_map_sg failed: no entries?\n");
+               return -ENOMEM;
+       }
        DBGA("pci_map_sg: %ld entries\n", out - start);
 
        return out - start;
@@ -699,7 +703,7 @@ static int alpha_pci_map_sg(struct device *dev, struct 
scatterlist *sg,
           entries.  Unmap them now.  */
        if (out > start)
                pci_unmap_sg(pdev, start, out - start, dir);
-       return 0;
+       return -ENOMEM;
 }
 
 /* Unmap a set of streaming mode DMA translations.  Again, cpu read
-- 
2.20.1