> > On Fri, Jun 14, 2019 at 01:28:47AM +0530, Kashyap Desai wrote: > > Is there any changes in API blk_queue_virt_boundary? I could not find > > relevant code which account for this. Can you help ? > > Which git repo shall I use for testing ? That way I can confirm, I > > didn't miss relevant changes. > > Latest mainline plus the series (which is about to get resent). > blk_queue_virt_boundary now forced an unlimited max_hw_sectors as that is > how PRP-like schemes work, to work around a block driver merging bug. But > we also need to communicate that limit to the DMA layer so that we don't set > a smaller iommu segment size limitation. > > > >From your above explanation, it means (after this patch) max segment > > >size > > of the MR controller will be set to 4K. > > Earlier it is possible to receive single SGE of 64K datalength (Since > > max seg size was 64K), but now the same buffer will reach the driver > > having 16 SGEs (Each SGE will contain 4K length). > > No, there is no more limit for the size of the segment at all, as for PRPs each > PRP is sort of a segment from the hardware perspective. > We just require the segments to not have gaps, as PRPs don't allow for that. Thanks for clarification. I have also observed that max_segment_size Is unchanged and it is 64K. > > That being said I think these patches are wrong for the case of megaraid or > mpt having both NVMe and SAS/ATA devices behind a single controller. > Is that a valid configuration? Yes. This is a valid configuration.
