linux/drivers/s390/scsi/zfcp_scsi.c, branch v5.16-rc1

scsi: zfcp: Switch to attribute groups

2021-10-17T01:45:53Z

struct device supports attribute groups directly but does not support struct device_attribute directly. Hence switch to attribute groups. Link: https://lore.kernel.org/r/20211012233558.4066756-7-bvanassche@acm.org Acked-by: Benjamin Block Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen

scsi: zfcp_scsi: Call scsi_done() directly

2021-10-17T01:28:44Z

Conditional statements are faster than indirect calls. Hence call scsi_done() directly. Link: https://lore.kernel.org/r/20211007202923.2174984-8-bvanassche@acm.org Acked-by: Benjamin Block Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen

scsi: core: Introduce scsi_build_sense()

2021-06-01T02:48:21Z

Introduce scsi_build_sense() as a wrapper around scsi_build_sense_buffer() to format the buffer and set the correct SCSI status. Link: https://lore.kernel.org/r/20210427083046.31620-8-hare@suse.de Reviewed-by: Bart Van Assche Reviewed-by: Christoph Hellwig Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: zfcp: Move allocation of the shost object to after xconf- and xport-data

2020-05-12T03:19:52Z

At the moment we allocate and register the Scsi_Host object corresponding to a zfcp adapter (FCP device) very early in the life cycle of the adapter - even before we fully discover and initialize the underlying firmware/hardware. This had the advantage that we could already use the Scsi_Host object, and fill in all its information during said discover and initialize. Due to commit 737eb78e82d5 ("block: Delay default elevator initialization") (first released in v5.4), we noticed a regression that would prevent us from using any storage volume if zfcp is configured with support for DIF or DIX (zfcp.dif=1 || zfcp.dix=1). Doing so would result in an illegal memory access as soon as the first request is sent with such an configuration. As example for a crash resulting from this: scsi host0: scsi_eh_0: sleeping scsi host0: zfcp qdio: 0.0.1900 ZFCP on SC 4bd using AI:1 QEBSM:0 PRI:1 TDD:1 SIGA: W AP scsi 0:0:0:0: scsi scan: INQUIRY pass 1 length 36 Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000483 Fault in home space mode while using kernel ASCE. AS:0000000035c7c007 R3:00000001effcc007 S:00000001effd1000 P:000000000000003d Oops: 0004 ilc:3 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: ... CPU: 1 PID: 783 Comm: kworker/u760:5 Kdump: loaded Not tainted 5.6.0-rc2-bb-next+ #1 Hardware name: ... Workqueue: scsi_wq_0 fc_scsi_scan_rport [scsi_transport_fc] Krnl PSW : 0704e00180000000 000003ff801fcdae (scsi_queue_rq+0x436/0x740 [scsi_mod]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0fffffffffffffff 0000000000000000 0000000187150120 0000000000000000 000003ff80223d20 000000000000018e 000000018adc6400 0000000187711000 000003e0062337e8 00000001ae719000 0000000187711000 0000000187150000 00000001ab808100 0000000187150120 000003ff801fcd74 000003e0062336a0 Krnl Code: 000003ff801fcd9e: e310a35c0012 lt %r1,860(%r10) 000003ff801fcda4: a7840010 brc 8,000003ff801fcdc4 #000003ff801fcda8: e310b2900004 lg %r1,656(%r11) >000003ff801fcdae: d71710001000 xc 0(24,%r1),0(%r1) 000003ff801fcdb4: e310b2900004 lg %r1,656(%r11) 000003ff801fcdba: 41201018 la %r2,24(%r1) 000003ff801fcdbe: e32010000024 stg %r2,0(%r1) 000003ff801fcdc4: b904002b lgr %r2,%r11 Call Trace: [<000003ff801fcdae>] scsi_queue_rq+0x436/0x740 [scsi_mod] ([<000003ff801fcd74>] scsi_queue_rq+0x3fc/0x740 [scsi_mod]) [<00000000349c9970>] blk_mq_dispatch_rq_list+0x390/0x680 [<00000000349d1596>] blk_mq_sched_dispatch_requests+0x196/0x1a8 [<00000000349c7a04>] __blk_mq_run_hw_queue+0x144/0x160 [<00000000349c7ab6>] __blk_mq_delay_run_hw_queue+0x96/0x228 [<00000000349c7d5a>] blk_mq_run_hw_queue+0xd2/0xe0 [<00000000349d194a>] blk_mq_sched_insert_request+0x192/0x1d8 [<00000000349c17b8>] blk_execute_rq_nowait+0x80/0x90 [<00000000349c1856>] blk_execute_rq+0x6e/0xb0 [<000003ff801f8ac2>] __scsi_execute+0xe2/0x1f0 [scsi_mod] [<000003ff801fef98>] scsi_probe_and_add_lun+0x358/0x840 [scsi_mod] [<000003ff8020001c>] __scsi_scan_target+0xc4/0x228 [scsi_mod] [<000003ff80200254>] scsi_scan_target+0xd4/0x100 [scsi_mod] [<000003ff802d8b96>] fc_scsi_scan_rport+0x96/0xc0 [scsi_transport_fc] [<0000000034245ce8>] process_one_work+0x458/0x7d0 [<00000000342462a2>] worker_thread+0x242/0x448 [<0000000034250994>] kthread+0x15c/0x170 [<0000000034e1979c>] ret_from_fork+0x30/0x38 INFO: lockdep is turned off. Last Breaking-Event-Address: [<000003ff801fbc36>] scsi_add_cmd_to_list+0x9e/0xa8 [scsi_mod] Kernel panic - not syncing: Fatal exception: panic_on_oops While this issue is exposed by the commit named above, this is only by accident. The real issue exists for longer already - basically since it's possible to use blk-mq via scsi-mq, and blk-mq pre-allocates all requests for a tag-set during initialization of the same. For a given Scsi_Host object this is done when adding the object to the midlayer (`scsi_add_host()` and such). In `scsi_mq_setup_tags()` the midlayer calculates how much memory is required for a single scsi_cmnd, and its additional data, which also might include space for additional protection data - depending on whether the Scsi_Host has any form of protection capabilities (`scsi_host_get_prot()`). The problem is now thus, because zfcp does this step before we actually know whether the firmware/hardware has these capabilities, we don't set any protection capabilities in the Scsi_Host object. And so, no space is allocated for additional protection data for requests in the Scsi_Host tag-set. Once we go through discover and initialize the FCP device firmware/hardware fully (this is done via the firmware commands "Exchange Config Data" and "Exchange Port Data") we find out whether it actually supports DIF and DIX, and we set the corresponding capabilities in the Scsi_Host object (in `zfcp_scsi_set_prot()`). Now the Scsi_Host potentially has protection capabilities, but the already allocated requests in the tag-set don't have any space allocated for that. When we then trigger target scanning or add scsi_devices manually, the midlayer will use requests from that tag-set, and before sending most requests, it will also call `scsi_mq_prep_fn()`. To prepare the scsi_cmnd this function will check again whether the used Scsi_Host has any protection capabilities - and now it potentially has - and if so, it will try to initialize the assumed to be preallocated structures and thus it causes the crash, like shown above. Before delaying the default elevator initialization with the commit named above, we always would also allocate an elevator for any scsi_device before ever sending any requests - in contrast to now, where we do it after device-probing. That elevator in turn would have its own tag-set, and that is initialized after we went through discovery and initialization of the underlying firmware/hardware. So requests from that tag-set can be allocated properly, and if used - unless the user changes/disabled the default elevator - this would hide the underlying issue. To fix this for any configuration - with or without an elevator - we move the allocation and registration of the Scsi_Host object for a given FCP device to after the first complete discovery and initialization of the underlying firmware/hardware. By doing that we can make all basic properties of the Scsi_Host known to the midlayer by the time we call `scsi_add_host()`, including whether we have any protection capabilities. To do that we have to delay all the accesses that we would have done in the past during discovery and initialization, and do them instead once we are finished with it. The previous patches ramp up to this by fencing and factoring out all these accesses, and make it possible to re-do them later on. In addition we make also use of the diagnostic buffers we recently added with commit 92953c6e0aa7 ("scsi: zfcp: signal incomplete or error for sync exchange config/port data") commit 7e418833e689 ("scsi: zfcp: diagnostics buffer caching and use for exchange port data") commit 088210233e6f ("scsi: zfcp: add diagnostics buffer for exchange config data") (first released in v5.5), because these already cache all the information we need for that "re-do operation" - the information cached are always updated during xconf or xport data, so it won't be stale. In addition to the move and re-do, this patch also updates the function-documentation of `zfcp_scsi_adapter_register()` and changes how it reports if a Scsi_Host object already exists. In that case future recovery-operations can skip this step completely and behave much like they would do in the past - zfcp does not release a once allocated Scsi_Host object unless the corresponding FCP device is deconstructed completely. Link: https://lore.kernel.org/r/030dd6da318bbb529f0b5268ec65cebcd20fc0a3.1588956679.git.bblock@linux.ibm.com Reviewed-by: Steffen Maier Signed-off-by: Benjamin Block Signed-off-by: Martin K. Petersen

scsi: zfcp: Move fc_host updates during xport data handling into fenced function

2020-05-12T03:19:48Z

When executing exchange port data for a FCP device for the first time, or after an adapter recovery, we update several properties of the fibre channel host object which represents that FCP device. When moving the scsi host object allocation and registration - and thus also the fibre channel host object allocation - to after the first exchange config and exchange port data, this is not possible for the former case. Move all these update into separate, and fenced function that first checks whether the scsi host object already exists or not, before making the updates. During the first ever exchange port data in the adapter life cycle this will make the exchange port data handler skip over this update step, but we can repeat it later, after we allocated the scsi host object. For any further recovery of that adapter the work flow is only changed slightly because then the scsi host object already exists and we don't free it until we release the adapter completely at the end of its life cycle. Link: https://lore.kernel.org/r/ae454c2dc6da0b02907c489af91d0b211d331825.1588956679.git.bblock@linux.ibm.com Reviewed-by: Steffen Maier Signed-off-by: Benjamin Block Signed-off-by: Martin K. Petersen

scsi: zfcp: Move shost updates during xconfig data handling into fenced function

2020-05-12T03:19:47Z

When executing exchange config data for a FCP device for the first time, or after an adapter recovery, we update several properties of the scsi host or fibre channel host object that represent that FCP device. When moving the scsi host object allocation and registration - and thus also the fibre channel host object allocation - to after the first exchange config and exchange port data, this is not possible for the former case. Move all these update into separate, and fenced function that first checks whether the scsi host object already exists or not, before making the updates. During the first ever exchange config data in the adapter life cycle this will make the exchange config data handler skip over this update step, but we can repeat it later, after we allocated the scsi host object. For any further recovery of that adapter the work flow is only changed slightly because then the scsi host object already exists and we don't free it until we release the adapter completely at the end of its life cycle. Link: https://lore.kernel.org/r/5fc3f4d38d4334f7aa595497c6f7865fb1102e0f.1588956679.git.bblock@linux.ibm.com Reviewed-by: Steffen Maier Signed-off-by: Benjamin Block Signed-off-by: Martin K. Petersen

scsi: zfcp: wire previously driver-specific sysfs attributes also to fc_host

2020-03-17T17:12:35Z

Manufacturer, HBA model, firmware version, and hardware version. Use the same value format as for the driver-specific attributes. Keep the driver-specific attributes for stable user space sysfs API. Link: https://lore.kernel.org/r/20200312174505.51294-4-maier@linux.ibm.com Reviewed-by: Jens Remus Reviewed-by: Benjamin Block Signed-off-by: Steffen Maier Signed-off-by: Martin K. Petersen

scsi: zfcp: expose fabric name as common fc_host sysfs attribute

2020-03-17T17:12:34Z

FICON Express8S or older, as well as card features newer than FICON Express16S+ have no certain firmware level requirement. FICON Express16S or FICON Express16S+ have the following minimum firmware level requirements to show a proper fabric name value: z13 machine FICON Express16S , MCL P08424.005 , LIC version 0x00000721 z14 machine FICON Express16S , MCL P42611.008 , LIC version 0x10200069 FICON Express16S+ , MCL P42625.010 , LIC version 0x10300147 Otherwise, the read value is not the fabric name. Each FCP channel of these card features might need one SAN fabric re-login after concurrent microcode update in order to show the proper fabric name. Possible ways to trigger a SAN fabric re-login are one of: Pull fibres between FCP channel port and SAN switch port on either side and re-plug, disable SAN switch port adjacent to FCP channel port and re-enable switch port, or at Service Element toggle off all CHPIDs of FCP channel over all LPARs and toggle CHPIDs on again. Zfcp operating subchannels (FCP devices) on such FCP channel recovers a fabric re-login. Initialize fabric name for any topology and have it an invalid WWPN 0x0 for anything but fabric topology. Otherwise for e.g. point-to-point topology one could see the initial -1 from fc_host_setup() and after a link unplug our fabric name would turn to 0x0 (with subsequent commit ("zfcp: fix fc_host attributes that should be unknown on local link down") and stay 0x0 on link replug. I did not initialize to 0x0 somewhere even earlier in the code path such that it would not flap from real to 0x0 to real on e.g. an exchange config data with fabric topology. Link: https://lore.kernel.org/r/20200312174505.51294-3-maier@linux.ibm.com Reviewed-by: Benjamin Block Reviewed-by: Jens Remus Signed-off-by: Steffen Maier Signed-off-by: Martin K. Petersen

scsi: zfcp: signal incomplete or error for sync exchange config/port data

2019-10-29T02:16:14Z

Adds a new FSF-Request status flag (ZFCP_STATUS_FSFREQ_XDATAINCOMPLETE) that signal that the data received using Exchange Config Data or Exchange Port Data was incomplete. This new flags is set in the respective handlers during the response path. With this patch, only the synchronous FSF-functions for each command got support for the new flag, otherwise it is transparent. Together with this new flag and already existing status flags the synchronous FSF-functions are extended to now detect whether the received data is complete, incomplete or completely invalid (this includes cases where a command ran into a timeout). This is now signaled back to the caller, where previously only failures on the request path would result in a bad return-code. For complete data the return-code remains 0. For incomplete data a new return-code -EAGAIN is added to the function-interface. For completely invalid data the already existing return-code -EIO is reused - formerly this was used to signal failures on the request path. Existing callers of the FSF-functions are adjusted so that they behave as before for return-code 0 and -EAGAIN, to not change the user-interface. As -EIO existed all along, it was already exposed to the user - and needed handling - and will now also be exposed in this new special case. Link: https://lore.kernel.org/r/e14f0702fa2b00a4d1f37c7981a13f2dd1ea2c83.1572018130.git.bblock@linux.ibm.com Reviewed-by: Steffen Maier Signed-off-by: Benjamin Block Signed-off-by: Martin K. Petersen

scsi: zfcp: fix to prevent port_remove with pure auto scan LUNs (only sdevs)

2019-05-30T01:52:31Z

When the user tries to remove a zfcp port via sysfs, we only rejected it if there are zfcp unit children under the port. With purely automatically scanned LUNs there are no zfcp units but only SCSI devices. In such cases, the port_remove erroneously continued. We close the port and this implicitly closes all LUNs under the port. The SCSI devices survive with their private zfcp_scsi_dev still holding a reference to the "removed" zfcp_port (still allocated but invisible in sysfs) [zfcp_get_port_by_wwpn in zfcp_scsi_slave_alloc]. This is not a problem as long as the fc_rport stays blocked. Once (auto) port scan brings back the removed port, we unblock its fc_rport again by design. However, there is no mechanism that would recover (open) the LUNs under the port (no "ersfs_3" without zfcp_unit [zfcp_erp_strategy_followup_success]). Any pending or new I/O to such LUN leads to repeated: Done: NEEDS_RETRY Result: hostbyte=DID_IMM_RETRY driverbyte=DRIVER_OK See also v4.10 commit 6f2ce1c6af37 ("scsi: zfcp: fix rport unblock race with LUN recovery"). Even a manual LUN recovery (echo 0 > /sys/bus/scsi/devices/H:C:T:L/zfcp_failed) does not help, as the LUN links to the old "removed" port which remains to lack ZFCP_STATUS_COMMON_RUNNING [zfcp_erp_required_act]. The only workaround is to first ensure that the fc_rport is blocked (e.g. port_remove again in case it was re-discovered by (auto) port scan), then delete the SCSI devices, and finally re-discover by (auto) port scan. The port scan includes an fc_rport unblock, which in turn triggers a new scan on the scsi target to freshly get new pure auto scan LUNs. Fix this by rejecting port_remove also if there are SCSI devices (even without any zfcp_unit) under this port. Re-use mechanics from v3.7 commit d99b601b6338 ("[SCSI] zfcp: restore refcount check on port_remove"). However, we have to give up zfcp_sysfs_port_units_mutex earlier in unit_add to prevent a deadlock with scsi_host scan taking shost->scan_mutex first and then zfcp_sysfs_port_units_mutex now in our zfcp_scsi_slave_alloc(). Signed-off-by: Steffen Maier Fixes: b62a8d9b45b9 ("[SCSI] zfcp: Use SCSI device data zfcp scsi dev instead of zfcp unit") Fixes: f8210e34887e ("[SCSI] zfcp: Allow midlayer to scan for LUNs when running in NPIV mode") Cc: #2.6.37+ Reviewed-by: Benjamin Block Signed-off-by: Martin K. Petersen