On Sat, Mar 13, 2021 at 11:02:41AM +0800, Zhu Yanjun wrote: > On Fri, Mar 12, 2021 at 10:01 PM Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > > > > On Fri, Mar 12, 2021 at 09:49:52PM +0800, Zhu Yanjun wrote: > > > In short, the sg list from __sg_alloc_table_from_pages is different > > > from the sg list from ib_umem_add_sg_table. > > > > I don't care about different. Tell me what is wrong with what we have > > today. > > > > I thought your first message said the sgl's were too small, but now > > you seem to say they are too big? > > Sure. > > The sg list from __sg_alloc_table_from_pages, length of sg is too big. > And the dma address is like the followings: > > " > sg_dma_address(sg):0x4b3c1ce000 > sg_dma_address(sg):0x4c3c1cd000 > sg_dma_address(sg):0x4d3c1cc000 > sg_dma_address(sg):0x4e3c1cb000 > " Ok, so how does too big a dma segment side cause __sg_alloc_table_from_pages() to return sg elements that are too small? I assume there is some kind of maths overflow here? Jason
