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2016-02-23scsi_dh: add 'rescan' callbackHannes Reinecke
If a device needs to be rescanned the device_handler might need to be rechecked, too. So add a 'rescan' callback to the device handler and call it upon scsi_rescan_device(). The rescan callback will be invoked from the Unit Attention handling of ASC/ASCQ 3F 03 (INQUIRY DATA HAS CHANGED). Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-02-23scsi_dh_alua: Use separate alua_port_group structureHannes Reinecke
The port group needs to be a separate structure as several LUNs might belong to the same group. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ewan Milne <emilne@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2015-08-28scsi_dh: kill struct scsi_dh_dataChristoph Hellwig
Add a ->handler and a ->handler_data field to struct scsi_device and kill this indirection. Also move struct scsi_device_handler to scsi_dh.h so that changes to it don't require rebuilding every SCSI LLDD. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28scsi_dh: integrate into the core SCSI codeChristoph Hellwig
Stop building scsi_dh as a separate module and integrate it fully into the core SCSI code with explicit callouts at bus scan time. For now the callouts are placed at the same point as the old bus notifiers were called, but in the future we will be able to look at ALUA INQUIRY data earlier on. Note that this also means that the device handler modules need to be loaded by the time we scan the bus. The next patches will add support for autoloading device handlers at bus scan time to make sure they are always loaded if they are enabled in the kernel config. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28dm-mpath, scsi_dh: request scsi_dh modules in scsi_dh, not dm-mpathChristoph Hellwig
This way we can reused the same code any attachment method, not just those requested from dm-mpath. [jejb: fixup checkpatch error] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28dm-mpath, scsi_dh: don't let dm detach device handlersChristoph Hellwig
While allowing dm-mpath to attach device handlers is a functionality we need for backwards compatibility reason there is no reason to reference count them and detach them if dm-mpath stops using the device for some reason. If the device handler works for the given device it can just stay attached, and we can take the retain_hw_handler codepath. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Hannes Reinecke <hare@Suse.de> Signed-off-by: James Bottomley <JBottomley@Odin.com>
2012-07-20[SCSI] scsi_dh: add scsi_dh_attached_handler_nameMike Snitzer
Introduce scsi_dh_attached_handler_name() to retrieve the name of the scsi_dh that is attached to the scsi_device associated with the provided request queue. Returns NULL if a scsi_dh is not attached. Also, fix scsi_dh_{attach,detach} function header comments to document @q rather than @sdev. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Tested-by: Babu Moger <babu.moger@netapp.com> Reviewed-by: Chandra Seetharaman <sekharan@us.ibm.com> Acked-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2009-12-04[SCSI] scsi_dh: Change the scsidh_activate interface to be asynchronousChandra Seetharaman
Make scsi_dh_activate() function asynchronous, by taking in two additional parameters, one is the callback function and the other is the data to call the callback function with. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2009-08-22[SCSI] scsi_dh: add the interface scsi_dh_set_params()Chandra Seetharaman
When we moved the device handler functionality from dm layer to SCSI layer we dropped the parameter functionality. This path adds an interface to scsi dh layer to set device handler parameters. Basically, multipath layer need to create a string with all the parameters and call scsi_dh_set_params() after it called scsi_dh_attach() on a device. If a device handler provides such an interface it will handle the parameters as it expects them. Reported-by: Eddie Williams <Eddie.Williams@steeleye.com> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Tested-by: Eddie Williams <Eddie.Williams@steeleye.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2008-07-26[SCSI] scsi_dh: attach to hardware handler from dm-mpathHannes Reinecke
multipath keeps a separate device table which may be more current than the built-in one. So we should make sure to always call ->attach whenever a multipath map with hardware handler is instantiated. And we should call ->detach on removal, too. [sekharan: update as per comments from agk] Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-07-26[SCSI] scsi_dh: Update EMC handlerHannes Reinecke
This patch converts the EMC device handler to use a proper state machine. We now also parse the extended INQUIRY information to determine if long trespass commands are supported. And we're now using the long trespass command correctly. And finally there's now an check at init time to refuse to attach to devices not supporting EMC-specific VPD pages. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-07-15[SCSI] scsi_dh: fix kconfig related build errorsChandra Seetharaman
Do not automatically "select" SCSI_DH for dm-multipath. If SCSI_DH doesn't exist,just do not allow hardware handlers to be used. Handle SCSI_DH being a module also. Make sure it doesn't allow DM_MULTIPATH to be compiled in when SCSI_DH is a module. [jejb: added comment for Kconfig syntax] Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-06-05[SCSI] scsi_dh: add infrastructure for SCSI Device HandlersChandra Seetharaman
Some of the storage devices (that can be accessed through multiple paths), do need some special handling for 1. Activating the passive path of the storage access. 2. Decode and handle the special sense codes returned by the devices. 3. Handle the I/Os being sent to the passive path, especially during the device probe time. when accessed through multiple paths. As of today this special device handling is done at the dm-multipath layer using dm-handlers. That works well for (1); for (2) to be handled at dm layer, scsi sense information need to be exported from SCSI to dm-layer, which is not very attractive; (3) cannot be done at all at the dm layer. Device handler has been moved to SCSI mainly to handle (2) and (3) properly. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>