FUJITA Tomonori wrote: > The bug reporter said that copying stooped but it should not > happen. It doesn't happen with SCSI (copying can continue a bit > slowly). dma mapping errors are transient so SCSI retries. ... > If the bug report is true, then the FireWire stack or the driver (or > both) has problems. Make sure that FireWire can work even with dma > mapping failures. sbp2_scsi_queuecommand returns SCSI_MLQUEUE_HOST_BUSY if DMA mapping failed. Isn't this what should happen? However, both usb-storage and firewire-sbp2 currently have a queudepth of only 1; if there are no DMA resources to map just this one SCSI request, how should the system be able to recover? It can wait, but it can't lower the part of the workload which is related to this particular copying operation (which, as the reporter wrote, ultimately stopped). I suppose there is something else* on the reporter's system which tied up too much swiotlb resources the whole time; and then just waiting a bit until the next queucommand won't get things going. *) The report does not sound like there was a DMA mappig leak caused by copying between usb-storage and firewire-sbp2. Else he would have hit the problem again even with increased swiotlb default size. > My dma mapping debug patchset might be useful: > > git://git.kernel.org/pub/scm/linux/kernel/git/tomo/linux-2.6-misc.git dmafault > > You can inject dma mapping failures per device: > > vine:/debug/pci/0000:00:1d.1# ls > interval probability space task-filter times verbose This could be handy, thanks. -- Stefan Richter -=====-==--= ---= =-=-= http://arcgraph.de/sr/ -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
