Hi Christoph, as discussed it would make sense to use the request->tag in eg scmd_printk() to identify the command. Which I duly did, only to figure out that the tag is always '-1', ie tagging is not in use. (Which is okay from the SCSI side, seeing the TCQ is basically a SCSI parallel thing). Looking closer I found plenty of code for handling tags in the block layer (and the blk-mq stuff, of course), but virtually none of the non-SPI driver seems to be using them. Which makes the original idea a bit pointless, seeing that we need to identify the command _always_, and not just if the host happens to support tagging. Which leads me to some questions: - Is the stuff in blk-mq supposed to work as a superset of SCSI TCQ? - If so, should any HBAs with a queue depth > 1 (which does not support TCQ) set the tag of a command? (that's what I've initially thought would happen ...) - If not (and the ->tag field is basically unused), can't we have the HBA to fill in a value here? What I would like to see is to have the '->tag' field as an identification for the commands in flight. IE every HBA with a queue depth > 1 should be setting the tags. Which apparently was too much to hope for ... Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- 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
