Hi Stefan, I currently playing around with improving SCSI EH, optimizing command aborts and the like.
And, supposing it to be a nice testbed, tried to make things work with virtio_scsi. However, looking at the code there I've found virtscsi_tmf() just uses 'wait_for_completion', with no timeout specified. So in effect any abort might stall forever. Wouldn't it be more sensible to use 'wait_for_completion_timeout' here, to allow the error escalation to continue? This would especially be useful when running with multipathing, as the underlying device might stall, and aio_cancel() doesn't work reliably, if at all. Also I've found that there is no host reset. Currently the virtio semantics seem to require reliable communication, ie for every command send there _has_ to be a response. Long and painful experience with RAID HBAs has shown that this model works okay for the lower-level escalations, but you absolutely need a host reset to restore communication. In the case of virtio I would think that a virtio-level reset for host_reset would be a sensible idea. Any opinions from your side? Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage h...@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
