On 01/24/2013 04:38 AM, Hannes Reinecke wrote: > On 01/24/2013 01:19 AM, Bart Van Assche wrote: >> On Fri, Jan 18, 2013 at 9:27 AM, Ewan D. Milne <emilne@xxxxxxxxxx> wrote: >>> This patch set adds changes to the SCSI mid-layer, sysfs and scsi_debug >>> to provide enhanced support for Unit Attention conditions, as well as >>> detection of reported sense data overflow conditions and some changes >>> to sense data processing. It also adds a uevent when the reported >>> capacity changes on an sd device. >>> >>> There was some discussion about this a couple of years ago on the >>> linux-scsi >>> mailing list: http://marc.info/?l=linux-scsi&m=129702506514742&w=2 >>> Although one approach is to send all SCSI sense data to a userspace >>> daemon >>> for processing, this patch set does not take that approach due to the >>> difficulty in reliably delivering all of the data. An interesting UA >>> condition might not be delivered due to a flood of media errors, for >>> example. >>> >>> The mechanism used is to flag when certain UA ASC/ASCQ codes are >>> received >>> that report asynchronous changes to the storage device configuration. >>> An appropriate uevent is then generated for the scsi_device or >>> scsi_target >>> object. An aggregation mechanism is used to avoid generating uevents at >>> too high a rate, and to coalesce multiple UAs reported by LUNs on the >>> same target for a REPORTED LUNS DATA HAS CHANGED sense code. >> >> Does this patch series add a function that allows SCSI LLDs to report >> AEN data to the SCSI core ? What if a SCSI target reports a LUN >> inventory change via AER to e.g. the iSCSI initiator and that >> initiator ignores the AEN data ? Will that result in AEN data being >> ignored and no automatic LUN rescanning ? >> > Well, first and foremost we _don't_ have automatic LUN rescanning. > This patchset just puts in the infrastructure that userspace can know > _when_ a LUN rescan might be in order. > > As for AEN, does iSCSI _do_ AEN? I thought it got removed ... The AEN is sent to userspace right now. > > If it does, though, it should schedule an event on its own whenever an > AER is received. The same goes for LLDDs with vendor-specific AENs; > thinking of megaraid_sas here ... > Yeah. It would be nicer if there was a wrapper around this code: +#ifdef CONFIG_SCSI_ENHANCED_UA + struct scsi_target *starget = scsi_target(sdev); + if (atomic_xchg(&starget->lun_change_reported, 1) == 0) + schedule_delayed_work(&starget->ua_dwork, 2*HZ); + scmd_printk(KERN_WARNING, scmd, + "Reported LUNs data has changed"); +#else so drivers do not have to have to duplicate and know that low level of details. -- 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
