[PATCH v2 05/21] alpha: return error code from alpha_pci_map_sg()

From: Logan Gunthorpe (logang@xxxxxxxxxxxx)
Date: Fri Jul 23 2021 - 13:51:02 EST


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 EIO.

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..21f9ac101324 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 -EIO;
+ 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