4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
commit 6b7df3ce92ac82ec3f4a2953b6fed77da7b38aaa upstream.
__s390_dma_map_sg maps a dma-contiguous area. Although we only map
whole pages we have to take into account that the area doesn't start
or stop at a page boundary because we use the dma address to loop
over the individual sg entries. Failing to do that might lead to an
access of the wrong sg entry.
Fixes: ee877b81c6b9 ("s390/pci_dma: improve map_sg")
Reported-and-tested-by: Christoph Raisch <raisch@xxxxxxxxxx>
Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/pci/pci_dma.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -419,6 +419,7 @@ static int __s390_dma_map_sg(struct devi
size_t size, dma_addr_t *handle,
enum dma_data_direction dir)
{
+ unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
dma_addr_t dma_addr_base, dma_addr;
int flags = ZPCI_PTE_VALID;
@@ -426,8 +427,7 @@ static int __s390_dma_map_sg(struct devi
unsigned long pa = 0;
int ret;
- size = PAGE_ALIGN(size);
- dma_addr_base = dma_alloc_address(dev, size >> PAGE_SHIFT);
+ dma_addr_base = dma_alloc_address(dev, nr_pages);
if (dma_addr_base == DMA_ERROR_CODE)
return -ENOMEM;
@@ -436,26 +436,27 @@ static int __s390_dma_map_sg(struct devi
flags |= ZPCI_TABLE_PROTECTED;
for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
- pa = page_to_phys(sg_page(s)) + s->offset;
- ret = __dma_update_trans(zdev, pa, dma_addr, s->length, flags);
+ pa = page_to_phys(sg_page(s));
+ ret = __dma_update_trans(zdev, pa, dma_addr,
+ s->offset + s->length, flags);
if (ret)
goto unmap;
- dma_addr += s->length;
+ dma_addr += s->offset + s->length;
}
ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
if (ret)
goto unmap;
*handle = dma_addr_base;
- atomic64_add(size >> PAGE_SHIFT, &zdev->mapped_pages);
+ atomic64_add(nr_pages, &zdev->mapped_pages);
return ret;
unmap:
dma_update_trans(zdev, 0, dma_addr_base, dma_addr - dma_addr_base,
ZPCI_PTE_INVALID);
- dma_free_address(dev, dma_addr_base, size >> PAGE_SHIFT);
+ dma_free_address(dev, dma_addr_base, nr_pages);
zpci_err("map error:\n");
zpci_err_dma(ret, pa);
return ret;
--
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