[PATCH 16/31] s390: handle page-less SG entries

Christoph Hellwig
2015-08-12T07:05:35Z

Use sg_phys() instead of page_to_phys(sg_page(sg)) so that we don't
require a page structure for all DMA memory.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/s390/pci/pci_dma.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 6fd8d58..aae5a47 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -272,14 +272,13 @@ int dma_set_mask(struct device *dev, u64 mask)
}
EXPORT_SYMBOL_GPL(dma_set_mask);

-static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
- unsigned long offset, size_t size,
+static dma_addr_t s390_dma_map_phys(struct device *dev, unsigned long pa,
+ size_t size,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
unsigned long nr_pages, iommu_page_index;
- unsigned long pa = page_to_phys(page) + offset;
int flags = ZPCI_PTE_VALID;
dma_addr_t dma_addr;

@@ -301,7 +300,7 @@ static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,

if (!dma_update_trans(zdev, pa, dma_addr, size, flags)) {
atomic64_add(nr_pages, &zdev->mapped_pages);
- return dma_addr + (offset & ~PAGE_MASK);
+ return dma_addr + (pa & ~PAGE_MASK);
}

out_free:
@@ -312,6 +311,16 @@ out_err:
return DMA_ERROR_CODE;
}

+static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction direction,
+ struct dma_attrs *attrs)
+{
+ unsigned long pa = page_to_phys(page) + offset;
+
+ return s390_dma_map_phys(dev, pa, size, direction, attrs);
+}
+
static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
size_t size, enum dma_data_direction direction,
struct dma_attrs *attrs)
@@ -384,8 +393,7 @@ static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
int i;

for_each_sg(sg, s, nr_elements, i) {
- struct page *page = sg_page(s);
- s->dma_address = s390_dma_map_pages(dev, page, s->offset,
+ s->dma_address = s390_dma_map_phys(dev, sg_phys(s),
s->length, dir, NULL);
if (!dma_mapping_error(dev, s->dma_address)) {
s->dma_length = s->length;
--
1.9.1