Muli -- I just ran tests on an IBM system with a Calgary iommu that Ed
Pollard pointed me at.
dma_ops_alloc_addresses() does not have the option to return
size-aligned values. This means that
pci_alloc_consistent()/dma_alloc_coherent() will return unaligned values
to callers when the lower 4G of memory not available.
Additionally, a quick test shows that in dma_ops_alloc_addresses()
boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
PAGE_SIZE) >> PAGE_SHIFT;
may return 0 in the same manner I've been pointing out -- if
dma_get_seg_boundary(dev) returns 0xffffffff and 1 is added to that
result, boundary_size = 0. Then you BUG() in the iommu-helper code.
Jesse pointed out to me that my fix on that line is incorrect. _If_
this is not a compiler issue (I've emailed jakub privately and cc'd him
on this email) then a better fix would be to do (sorry for the
cut-and-paste):
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -78,7 +78,7 @@ static inline unsigned int dma_set_max_seg_size(struct
device
static inline unsigned long dma_get_seg_boundary(struct device *dev)
{
return dev->dma_parms ?
- dev->dma_parms->segment_boundary_mask : 0xffffffff;
+ dev->dma_parms->segment_boundary_mask : 0xffffffffUL;
}
However, I'm still waiting for clarification from jakub before
submitting again with that chunk.
P.
--
