On Mon, Jan 24, 2011 at 9:04 AM, Hannes Reinecke <hare@xxxxxxx> wrote: > > Currently sense codes have two problems: > > - They are limited to 96 bytes. Anything larger than that will just > be discarded (or crash with your patch above :-) > - They inherit the same lifetime than the scsi command. But for any > decent handling you really need to push them into some > asynchronous context as you might well be within an interrupt > handler here. > > I'm currently working on a handling framework using relayfs > (basically blktrace for SCSI Unit Attention); I can be doing a short > presentation at LSF if requested. (replying to an e-mail of two months ago) There is another scenario where better unit attention support would help. Both the LIO-port and the SCST-port of the ibmvstgt driver suffer from the same race condition during reboot of the virtual I/O server (VIOS). Since the ibmvscsic driver reconnects to the ibmvscsis driver as soon as the ibmvscsis driver has been loaded the client reconnects before all LUNs have been configured in the VIOS system. So even if the target implementation generates an INQUIRY DATA HAS CHANGED unit attention condition for each LUN change, LUNs will have to be rescanned explicitly at the initiator side in order to get the initiator state in sync with the target state. Also, when using iSCSI, it would beneficial if LUN changes at the target would result in an automatic update of the LUNs reported by the initiator. This is not yet the case when using a Linux iSCSI initiator because the INQUIRY DATA HAS CHANGED unit attention condition is ignored by the Linux SCSI stack. Bart. -- 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
