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2014-12-04Revert "[SCSI] mpt3sas: Remove phys on topology change"Sreekanth Reddy1-4/+1
This reverts commit 963ba22b90a955363644cd397b20226928eab976 ("mpt3sas: Remove phys on topology change") Reverting the previous mpt3sas drives patch changes, since we will observe below issue Issue: Drives connected Enclosure/Expander will unregister with SCSI Transport Layer, if any one remove and add expander cable with in DMD (Device Missing Delay) time period or even any one power-off and power-on the Enclosure with in the DMD period. Cc: <stable@vger.kernel.org> Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-12-04Revert "[SCSI] mpt2sas: Remove phys on topology change."Sreekanth Reddy1-4/+1
This reverts commit 3520f9c779bed098ca76dd3fb6377264301d57ed ("mpt2sas: Remove phys on topology change") Reverting the previous mpt2sas drives patch changes, since we will observe below issue Issue: Drives connected Enclosure/Expander will unregister with SCSI Transport Layer, if any one remove and add expander cable with in DMD (Device Missing Delay) time period or even any one power-off and power-on the Enclosure with in the DMD period. Cc: <stable@vger.kernel.org> Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-12-04esas2r: Correct typos of "validate" in a commentBoris Bodemann1-2/+2
Correct typos of "validate" in a comment Signed-off-by: Boris Bodemann <bobo.barbarossa@gmail.com> Acked-by: Bradley Grove <bgrove@attotech.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-12-04fc: FCP_PTA_SIMPLE is 0Christoph Hellwig2-9/+2
Not need to have an if/else to either assign FCP_PTA_SIMPLE or 0 to a variable. Btw, it seems we really should factor generating a fcp cmnd from a scsi_cmnd into a common helper. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-12-04ibmvfc: remove unused tag variableChristoph Hellwig1-1/+0
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> 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: Brian King <brking@linux.vnet.ibm.com>
2014-12-04scsi: remove MSG_*_TAG definesChristoph Hellwig18-58/+58
For SPI drivers use the message definitions from scsi.h, and for target drivers introduce a new TCM_*_TAG namespace. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com
2014-12-04scsi: remove scsi_set_tag_typeChristoph Hellwig2-16/+1
There is no benefit over just setting sdev->simple_tags directly. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-12-04scsi: remove scsi_get_tag_typeChristoph Hellwig3-16/+3
Both remaining users are better of just checking sdev->simple_tags directly. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-12-04scsi: never drop to untagged mode during queue ramp downChristoph Hellwig1-6/+0
Dropping to untagged mode when ramping down a queue due to QUEUE FULL events has two problems: - nothing in the midlayer or drivers ever moves back to tagged mode during queue ramp up. - cmd_per_lun isn't the untagged queue depth for many modern drivers that can handle multiple untagged commands, and this is the only place in the midlayer assuming that. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-12-04scsi: remove ->change_queue_type methodChristoph Hellwig25-171/+4
Since we got rid of ordered tag support in 2010 the prime use case of switching on and off ordered tags has been obsolete. The other function of enabling/disabling tagging entirely has only been correctly implemented by the 53c700 driver and isn't generally useful. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-27libsas: remove task_collector modeChristoph Hellwig20-556/+97
The task_collector mode (or "latency_injector", (C) Dan Willians) is an optional I/O path in libsas that queues up scsi commands instead of directly sending it to the hardware. It generall increases latencies to in the optiomal case slightly reduce mmio traffic to the hardware. Only the obsolete aic94xx driver and the mvsas driver allowed to use it without recompiling the kernel, and most drivers didn't support it at all. Remove the giant blob of code to allow better optimizations for scsi-mq in the future. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Dan Williams <dan.j.williams@intel.com>
2014-11-27wd719x: remove dma_cache_sync callOndrej Zary1-2/+0
Remove dma_cache_sync call to fix build on other architectures. Driver still works fine on x86 without that. Signed-off-by: Ondrej Zary <linux@rainbow-software.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25scsi_debug: add Report supported opcodes+tmfs; Compare and writeDouglas Gilbert1-19/+307
The Report supported operation codes command is very closely integrated into the table driven parser and very useful for testing it. Its cdb masks form the basis of the 'strict' parameter's checks. The Report supported TMFs command is a simple extension. The Compare and write command may even be useful, as it should be atomic due to the read-write lock that the driver uses on its backing store (ram). Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25scsi_debug: change SCSI command parser to table drivenDouglas Gilbert1-558/+833
The existing 'big switch' parser in queuecommand() is changed to a table driven parser. The old and new queuecommand() were moved in the source so diff would not shuffle them. Apart from the new tables most other changes are refactoring existing response code to be more easily called out of the table parser. The 'strict' parameter is added so that cdb_s can be checked for non-zero values in parts of the cdb that are reserved. Some other changes include: tweak request sense response when D_SENSE differs; support NDOB in Write Same(16); and fix crash in Get LBA Status when LBP was inactive. Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25scsi_debug: add Capacity Changed Unit AttentionDouglas Gilbert1-4/+24
Via sysfs the virtual_gb scsi_debug parameter can be changed while LUs are in use. If that changes, the 'Capacity data has changed' Unit Attention is queued on all LUs. Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25scsi_debug: append inject error flags onto scsi_cmnd objectDouglas Gilbert1-0/+68
The way the existing scsi_debug command parser associated various inject error flags to a command was difficult to replicate in the table driven parser. This patch adds infrastructure to append those flags to the end of a scsi_cmnd object with the cmd_size host template option. Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25scsi_debug: pinpoint invalid field in sense dataDouglas Gilbert1-50/+88
Use Sense Key Specific field in the sense data of an ILLEGAL REQUEST to optionally pinpoint the location of the problem field. This may be either in the cdb or the associated parameter list. Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25wd719x: Add firmware documentationOndrej Zary1-0/+21
Add documentation and script to obtain required firmware. Signed-off-by: Ondrej Zary <linux@rainbow-software.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25wd719x: Introduce Western Digital WD7193/7197/7296 PCI SCSI card driverOndrej Zary4-0/+1256
Introduce wd719x, a driver for Western Digital WD7193, WD7197 and WD7296 PCI SCSI controllers based on WD33C296A chip. Tested with WD7193 card. Signed-off-by: Ondrej Zary <linux@rainbow-software.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25eeprom-93cx6: Add (read-only) support for 8-bit modeOndrej Zary2-1/+65
Add read-only support for EEPROMs configured in 8-bit mode (ORG pin connected to GND). This will be used by wd719x driver. Signed-off-by: Ondrej Zary <linux@rainbow-software.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25esas2r: fix an oversight in setting return valueTomas Henzl1-1/+4
The patch moves an error code assigment to a 'default' case in the previous switch statement. Signed-off-by: Tomas Henzl <thenzl@redhat.com> Acked-by: Bradley Grove <bgrove@attotech.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25esas2r: fix an error path in esas2r_ioctl_handlerTomas Henzl1-3/+4
Is seems strange to manipulate nvram_semaphore when in this place, this patch fixes it. Signed-off-by: Tomas Henzl <thenzl@redhat.com> Acked-by: Bradley Grove <bgrove@attotech.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-25esas2r: fir error handling in do_fm_apiTomas Henzl1-5/+5
This patch fixes an error path and rearranges error handling. Signed-off-by: Tomas Henzl <thenzl@redhat.com> Acked-by: Bradley Grove <bgrove@attotech.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24tmscsim: replace by am53c974 driverHannes Reinecke6-3196/+4
The am53c974 is a re-implementation of the tmscsim driver, and provides the same functionality. So remove the tmscsim driver and make am53c974 an alias to tmscsim. Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: enable CONFIG2_FENAB for am53c974Hannes Reinecke2-0/+42
CONFIG2_FENAB ('feature enable') changed definition between chip revisions, from 'Latch SCSI Phase' to 'Latch SCSI Phase, display chip ID upon reset, and enable 24 bit addresses'. So only enable it for am53c974 where we know what it's doing. Acked-by: David S. Miller <davem@davemloft.net> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: let DMA driver provide a config2 valuePaolo Bonzini1-33/+37
On PCscsi, the FENAB configuration also enables 24-bit DMA transfer lengths (and provides the chip id in TCHI after reset). We want to be able to enable this parameter from the DMA driver. Check if the caller of scsi_esp_register provided a value for esp->config2. If this is the case, assume this is not an ESP100, skip the detection phase and leave esp->config2 untouched. It will be used in esp_reset_esp. Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: correctly detect am53c974Hannes Reinecke3-1/+33
The am53c974 returns the same ID as the FAS236, but implements things slightly differently. So detect the am53c974 by checking for ESP_CONFIG4 register. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24am53c974: BLAST residual handlingHannes Reinecke3-0/+36
The am53c974 has an design issue where a single byte might be left in the SCSI FIFO after a DMA transfer. As the handling code is currently untested add a WARN_ON() statement here. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24am53c974: add new driverHannes Reinecke3-0/+556
This patch adds a new implementation for the Tekram DC-390T / AMD AM53c974 SCSI controller, based on the generic esp_scsi infrastructure. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: use FIFO for command submissionHannes Reinecke2-17/+30
Using DMA for command submission has the drawback that it might generate additional DMA completion interrupts after the command has been submitted to the device. Additionally the am53c974 has a design flaw causing it to generate spurious interrupts even though DMA completion interrupts are not enabled. This can be avoided by using the FIFO for command submission. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: read status registersHannes Reinecke1-3/+5
A read to ESP_INTRPT will clear ESP_STATUS and ESP_SSTEP. So read all status registers in one go to avoid losing information. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: debug event and commandHannes Reinecke1-0/+15
Add new debug definitions for event and command logging. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: convert to dev_printkHannes Reinecke1-106/+106
Use dev_printk functions for correct device annotations. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: make number of tags configurableHannes Reinecke2-8/+7
Add a field 'num_tags' to the esp structure to allow drivers to overwrite the number of avialable tags if required. Default is ESP_DEFAULT_TAGS. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24esp_scsi: spellcheck 'driver'Hannes Reinecke1-1/+1
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24vmw_pscsi: simplify ->change_queue_depthChristoph Hellwig1-9/+1
Remove overly verbose debugging output that pokes into mid-layer internal structures that looks like copy & paste from the mpt2/3 drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-24mpt3sas: simplify ->change_queue_depthChristoph Hellwig1-26/+10
Merge two functions, and remove overly verbose debugging output that pokes into mid-layer internal structures. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-24mpt2sas: simplify ->change_queue_depthChristoph Hellwig1-29/+5
Merge two functions, and remove overly verbose debugging output that pokes into mid-layer internal structures. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-24scsi: drop reason argument from ->change_queue_depthChristoph Hellwig73-412/+155
Drop the now unused reason argument from the ->change_queue_depth method. Also add a return value to scsi_adjust_queue_depth, and rename it to scsi_change_queue_depth now that it can be used as the default ->change_queue_depth implementation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-24scsi: don't allow setting of queue_depth bigger than can_queueChristoph Hellwig9-30/+3
We won't ever queue more commands than the host allows. Instead of letting drivers either reject or ignore this case handle it in common code. Note that various driver use internal constant or variables that are assigned to both shost->can_queue and checked in ->change_queue_depth - I did remove those checks as well. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-24scsi: avoid ->change_queue_depth indirection for queue full trackingChristoph Hellwig30-244/+73
All drivers use the implementation for ramping the queue up and down, so instead of overloading the change_queue_depth method call the implementation diretly if the driver opts into it by setting the track_queue_depth flag in the host template. Note that a few drivers validated the new queue depth in their change_queue_depth method, but as we never go over the queue depth set during slave_configure or the sysfs file this isn't nessecary and can safely be removed. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Venkatesh Srinivas <venkateshs@google.com>
2014-11-24lpfc: remove queue_depth eventsChristoph Hellwig1-66/+0
James Smart said the userspace to consume these events never emerged. Given that these get in the way of the following patches remove support for them. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: James Smart <james.smart@emulex.com>
2014-11-24megaraid_sas: do not process IOCTLs and SCSI commands during driver removalSumit.Saxena@avagotech.com1-4/+15
Do not process any SCSI and IOCTL command further (return them with appropriate return values to callers), while driver removal is in progress or PCI shutdown is invoked. Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24megaraid_sas: dndinaness related bug fixesSumit.Saxena@avagotech.com2-14/+16
This patch addresses few endianness related bug fixes. Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24megaraid_sas: corrected return of wait_event from abort frame pathSumit.Saxena@avagotech.com1-1/+1
Corrected wait_event() call which was waiting for wrong completion status (0xFF). Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24megaraid_sas: make HBA operational after LD_MAP_SYNC DCMD in OCR pathSumit.Saxena@avagotech.com1-13/+13
In OCR(Online Controller Reset) path, driver sets adapter state to MEGASAS_HBA_OPERATIONAL before getting new RAID map. There will be a small window where IO will come from OS with old RAID map. This patch will update adapter state to MEGASAS_HBA_OPERATIONAL, only after driver has new RAID map to avoid any IOs getting build using old RAID map. Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24megaraid_sas: online Firmware upgrade support for Extended VD featureSumit.Saxena@avagotech.com4-57/+85
In OCR (Online Controller Reset) path, driver sets adapter state to MEGASAS_HBA_OPERATIONAL before getting new RAID map. There will be a small window where IO will come from OS with old RAID map. This patch will update adapter state to MEGASAS_HBA_OPERATIONAL, only after driver has new RAID map to avoid any IOs getting build using old RAID map. Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24megaraid_sas: update MAINTAINERS and copyright information for megaraid driversSumit.Saxena@avagotech.com6-43/+53
Update MAINTAINERS list and copyright information for megaraid_sas driver. Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-24megaraid_sas: driver version upgrade and remove some meta data of driverSumit.Saxena@avagotech.com2-26/+2
Update driver version and remove some meta data (release date and extended version) about megaraid_sas driver. Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-11-20zfcp: auto port scan resiliencyMartin Peschke6-14/+90
This patch improves the Fibre Channel port scan behaviour of the zfcp lldd. Without it the zfcp device driver may churn up the storage area network by excessive scanning and scan bursts, particularly in big virtual server environments, potentially resulting in interference of virtual servers and reduced availability of storage connectivity. The two main issues as to the zfcp device drivers automatic port scan in virtual server environments are frequency and simultaneity. On the one hand, there is no point in allowing lots of ports scans in a row. It makes sense, though, to make sure that a scan is conducted eventually if there has been any indication for potential SAN changes. On the other hand, lots of virtual servers receiving the same indication for a SAN change had better not attempt to conduct a scan instantly, that is, at the same time. Hence this patch has a two-fold approach for better port scanning: the introduction of a rate limit to amend frequency issues, and the introduction of a short random backoff to amend simultaneity issues. Both approaches boil down to deferred port scans, with delays comprising parts for both approaches. The new port scan behaviour is summarised best by: NEW: NEW: no_auto_port_rescan random rate flush backoff limit =wait adapter resume/thaw yes yes no yes* adapter online (user) no yes no yes* port rescan (user) no no no yes adapter recovery (user) yes yes yes no adapter recovery (other) yes yes yes no incoming ELS yes yes yes no incoming ELS lost yes yes yes no Implementation is straight-forward by converting an existing worker to a delayed worker. But care is needed whenever that worker is going to be flushed (in order to make sure work has been completed), since a flush operation cancels the timer set up for deferred execution (see * above). There is a small race window whenever a port scan work starts running up to the point in time of storing the time stamp for that port scan. The impact is negligible. Closing that gap isn't trivial, though, and would the destroy the beauty of a simple work-to-delayed-work conversion. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>