On Tue, Nov 27, 2012 at 09:47:48AM -0800, Laine Walker-Avina wrote: > On Tue, Nov 27, 2012 at 9:05 AM, Matthew Wilcox <[email protected]> wrote: > > Laine, when this occurs, what is the alignment of 'offset' in the sg > > entry you're looking at? If userspace is passing in an unaligned address, > > I don't think there's anything we do to try to align it. > > I thought this was the case as well, but it appears to be aligned > looking at the request in the user space program (fio using libaio in > this case) before the IO is submitted.
OK, so we have an aligned virtual address being translated into an unaligned DMA address. I have a suspicion ... are you using the swiotlb, or are you using a real IOMMU? Grep dmesg for 'IOMMU' if you're not sure. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
