This patch allows scsi drivers that expose virturalized fibre channel
devices but that do not expose rports to successfully rescan the scsi
bus via echo "- - -" > /sys/class/scsi_host/hostX/scan. Drivers can
create a pseudo rport and indicate FC_PORT_ROLE_FCP_DUMMY_INITIATOR as
the rport's role in fc_rport_identifiers. This insures that a valid
scsi_target_id is assigned to the newly created rport and it can meet
the requirements of fc_user_scan_tgt calling scsi_scan_target.
Signed-off-by: Cathy Avery <cavery@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Passed through SCSI targets may have transfer limits which come from the
host SCSI controller or something on the host side other than the target
itself.
To make this work properly, the hypervisor can adjust the target's VPD
information to advertise these limits. But for that to work, the guest
has to look at the VPD pages, which we won't do by default if it is an
SPC-2 device, even if it does actually support it.
This adds a workaround to address this, forcing devices attached to a
virtio-scsi controller to always check the VPD pages. This is modelled
on a similar workaround for the storvsc (Hyper-V) SCSI controller,
although that exists for slightly different reasons.
A specific case which causes this is a volume from IBM's IPR RAID
controller (which presents as an SPC-2 device, although it does support
VPD) passed through with qemu's 'scsi-block' device.
[mkp: fixed typo]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This patch fixes a potential buffer overflow in lpfc_nvme_info_show().
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Acked-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The check for an unsigned long being less than zero is always false so
it is a redundant check and can be removed.
Detected by static analysis with by PVS-Studio
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
mempool_alloc() cannot fail when passed GFP_NOIO or any other gfp
setting that is permitted to sleep. So remove this pointless code.
Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
storvsc_on_channel_callback is a void function and the return
statement at the end is not useful.
Found with checkpatch.
Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Use kcalloc for allocating an array instead of kzalloc with multiply,
kcalloc is the preferred API.
Found with checkpatch.
Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As an enhancement to distribute requests to multiple hardware queues, add the
infrastructure to hash a SCSI command into a particular hardware queue.
Support the following scenarios when deriving which queue to use: single
queue, tagging when SCSI-MQ enabled, and simple hash via CPU ID when SCSI-MQ
is disabled. Rather than altering the existing send API, the derived hardware
queue is stored in the AFU command where it can be used for sending a command
to the chosen hardware queue.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As staging for supporting multiple hardware queues, add an attribute to show
and set the current number of hardware queues for the host. Support specifying
a hard limit or a CPU affinitized value. This will allow the number of
hardware queues to be tuned by a system administrator.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Introduce multiple hardware queues to improve legacy I/O path performance.
Each hardware queue is comprised of a master context and associated I/O
resources. The hardware queues are initially implemented as a static array
embedded in the AFU. This will be transitioned to a dynamic allocation in a
later series to improve the memory footprint of the driver.
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The method used to decode asynchronous interrupts involves unnecessary loops
to match up bits that are set with corresponding entries in the asynchronous
interrupt information table. This algorithm is wasteful and does not scale
well as new status bits are supported.
As an improvement, use the for_each_set_bit() service to iterate over the
asynchronous status bits and refactor the information table such that it can
be indexed by bit position.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As a general cleanup, address all reasonable checkpatch warnings and
errors. These include enforcement of comment styles and including named
identifiers in function prototypes.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Validation statements to enforce assumptions about specific defines are not
being evaluated by the compiler due to the fact that they reside in a routine
that is not used. To activate them, call the routine as part of module
initialization. As an additional, related cleanup, remove the now-defunct
CXLFLASH_NUM_CMDS.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Devices supported by the cxlflash driver are fully coherent and do not require
a bus address mapping. Avoid unnecessary path length by using the virtual
address and length already present in the scatter-gather entry.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
An EEH during probe can lead to a crash as the recovery thread races with the
probe thread. To avoid this issue, introduce new states to fence out EEH
recovery until probe has completed. Also ensure the reset wait queue is
flushed during device removal to avoid orphaned threads.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Update the driver to allow for future cards with 4 ports.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Update the SISlite header to support 4 ports as outlined in the SISlite
specification. Address fallout from structure renames and refreshed
organization throughout the driver. Determine the number of ports supported by
a card from the global port selection mask register reset value.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As staging to support FC-related updates to the SISlite specification,
introduce helper routines to obtain references to FC resources that exist
within the global map. This will allow changes to the underlying global map
structure without impacting existing code paths.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
At present, the cxlflash driver only supports hardware with two FC ports. The
code was initially designed with this assumption and is dependent on having
two FC ports - adding more ports will break logic within the driver.
To mitigate this issue, remove the existing port assumptions and transition
the code to support more than two ports. As a side effect, clarify the
interpretation of the DK_CXLFLASH_ALL_PORTS_ACTIVE flag.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Transition from a static number of FC ports to a value that is derived during
probe. For now, a static value is used but this will later be based on the
type of card being configured.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As staging for future function, pass the config pointer instead of the AFU
pointer for port-related sysfs helper routines.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Currently, RRQ processing takes place on hardware interrupt context. This can
be a heavy burden in some environments due to the overhead encountered while
completing RRQ entries. In an effort to improve system performance, use the
IRQ polling API to schedule this processing on softirq context.
This function will be disabled by default until starting values can be
established for the hardware supported by this driver.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As further staging to support processing the HRRQ by other means, access to
the HRRQ needs to be serialized by a disabled lock. This will allow safe
access in other non-hardware interrupt contexts. In an effort to minimize the
period where interrupts are disabled, support is added to queue up commands
harvested from the RRQ such that they can be processed with hardware
interrupts enabled. While this doesn't offer any improvement with processing
on a hardware interrupt it will help when IRQ polling is supported and the
command completions can execute on softirq context.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
In order to support processing the HRRQ by other means (e.g. polling), the
processing portion of the current RRQ interrupt handler needs to be broken out
into a separate routine. This will allow RRQ processing from places other than
the RRQ hardware interrupt handler.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Trivial fix to spelling mistake in SNIC_ERR error message text, one
cannot have "Cann't".
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
For 1 bit ECC errors, those errors can be recovered by hw. But for
multi-bits ECC and AXI errors, there are something wrong with whole
module or system, so try reset the controller to recover those errors
instead of calling panic().
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
If a TMF timeouts (maybe due to unlikely scenario of an expander being
unplugged when TMF for remote device is active), when we eventually try
to free the slot, we crash as we dereference the slot's task, which has
already been released.
As a fix, add checks in the slot release code for a NULL task.
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This patch is a workaround for a SoC bug where an internal abort command
may timeout. In v2 hw, the channel should become idle in order to finish
abort process. If the target side has been sending HOLD, host side
channel failed to complete the frame to send, and can not enter the idle
state. Then internal abort command will timeout.
As this issue is only in v2 hw, we deal with it in the hw layer. Our
workaround solution is: If abort is not finished within a certain period
of time, we will check HOLD status. If HOLD has been sending, we will
send break command.
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This patch adds a workaround solution for a SoC bug which may cause SoC
logic fatal error when disabling a PHY. Then we find internal abort IO
timeout may occur, and the controller IO breakpoint may be corrupted.
We work around this SoC bug by optimizing the flow of disabling a PHY.
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This patch provides a workaround a SoC bug where SATA IPTTs for
different devices may conflict.
The workaround solution requests the following:
1. SATA device id must be even and not equal to SAS IPTT.
2. SATA device can not share the same IPTT with other SAS or
SATA device.
Besides we shall consider IPTT value 0 is reserved for another SoC bug
(STP device open link at firstly after SAS controller reset).
To sum up, the solution is: Each SATA device uses independent and
continuous 32 even IPTT from 64 to 4094, then v2 hw can only support 63
SATA devices. All SAS device(SSP/SMP devices) share odd IPTT value from
1 to 4095.
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
After resetting the controller, the process of scanning SATA disks
attached to an expander may fail occasionally. The issue is that the
controller can't close the STP link created by target if the max link
time is 0.
To workaround this issue, we reject STP link after resetting the
controller, and change the corresponding PHY to accept STP link only
after receiving data.
We do this check in cq interrupt handler. In order not to reduce
efficiency, we use an variable to control whether we should check and
change PHY to accept STP link.
The function phys_reject_stp_links_v2_hw() should be called after
resetting the controller.
The solution of another SoC bug "SATA IO timeout", that also uses the
same register to control STP link, is not effective before the PHY
accepts STP link.
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Directly call ELS request handler functions in fc_lport_recv_els_req
instead of saving the pointer to the handler's receive function and then
later dereferencing this pointer.
This makes the code a bit more obvious.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
sg_remove_sfp_usercontext() is clearing any sg requests, but needs to
take 'rq_list_lock' when modifying the list.
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
'Sg_request' is using a private list implementation; convert it to
standard lists.
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Check for a valid direction before starting the request, otherwise we
risk running into an assertion in the scsi midlayer checking for valid
requests.
[mkp: fixed typo]
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Link: http://www.spinics.net/lists/linux-scsi/msg104400.html
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The 'reserved' page array is used as a short-cut for mapping data,
saving us to allocate pages per request. However, the 'reserved' array
is only capable of holding one request, so this patch introduces a mutex
for protect 'sg_fd' against concurrent accesses.
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Unused.
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The ioctl SET_FORCE_LOW_DMA has never worked since the initial git
check-in, and the respective setting is nowadays handled correctly. So
disable it entirely.
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
There are several local or function parameter pointers that are being
assigned NULL after a kfree where and these have no effect and hence can
be removed.
Fixes various cppcheck warnings:
"Assignment of function parameter has no effect outside the
function. Did you forget dereferencing it"
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The redundant init_completion() here seems to be a cut&past error as
struct scsi_qla_host only has 4 completion elements to initialize, thus
the duplicate init_completion(disable_acb_comp) is simply removed.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
There hasn't been any reports for HBAs where asynchronous abort
would not work, so we should make it mandatory and remove
the fallback.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
scsi_eh_scmd_add() currently only will fail if no
error handler thread is started (which will never be the
case) or if the state machine encounters an illegal transition.
But if we're encountering an invalid state transition
chances is we cannot fixup things with the error handler.
So better add a WARN_ON for illegal host states and
make scsi_dh_scmd_add() a void function.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
If a failed command is retried and fails again we need
to enter SCSI EH, otherwise we will never be able to
recover the command.
To detect this situation we must not clear scmd->eh_eflags
when EH finishes but rather make it persistent throughout
the lifetime of the command.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
We now first try to call ->eh_abort_handler from a work queue, but libsas
was always failing that for no good reason. Allow async aborts.
Reviewed-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
When a command has timed out we always should be sending an
abort; with the previous code a failed abort might signal
SCSI EH to start, and all other timed out commands will
never be aborted, even though they might belong to a
different ITL nexus.
Cc: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
If sd_eh_action() decides to take the device offline there is
no point in returning FAILED, as taking the device offline
is the ultimate step in SCSI EH anyway.
So further escalation via SCSI EH is not likely to make a
difference and we can as well return SUCCESS.
Cc: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The current medium access timeout counter will be increased for
each command, so if there are enough failed commands we'll hit
the medium access timeout for even a single device failure and
the following kernel message is displayed:
sd H:C:T:L: [sdXY] Medium access timeout failure. Offlining disk!
Fix this by making the timeout per EH run, ie the counter will
only be increased once per device and EH run.
Fixes: 18a4d0a ("[SCSI] Handle disk devices which can not process medium access commands")
Cc: Ewan Milne <emilne@redhat.com>
Cc: Lawrence Obermann <loberman@redhat.com>
Cc: Benjamin Block <bblock@linux.vnet.ibm.com>
Cc: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
And get automatic MSI-X affinity for free.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The commit 08024885a2 ("ses: Add power_status to SES device slot")
introduced the 'power_status' attribute to enclosure components and
the associated callbacks.
There are 2 callbacks available to get the power status of a device:
1) ses_get_power_status() for 'struct enclosure_component_callbacks'
2) get_component_power_status() for the sysfs device attribute
(these are available for kernel-space and user-space, respectively.)
However, despite both methods being available to get power status
on demand, that commit also introduced a call to get power status
in ses_enclosure_data_process().
This dramatically increased the total probe time for SCSI devices
on larger configurations, because ses_enclosure_data_process() is
called several times during the SCSI devices probe and loops over
the component devices (but that is another problem, another patch).
That results in a tremendous continuous hammering of SCSI Receive
Diagnostics commands to the enclosure-services device, which does
delay the total probe time for the SCSI devices __significantly__:
Originally, ~34 minutes on a system attached to ~170 disks:
[ 9214.490703] mpt3sas version 13.100.00.00 loaded
...
[11256.580231] scsi 17:0:177:0: qdepth(16), tagged(1), simple(0),
ordered(0), scsi_level(6), cmd_que(1)
With this patch, it decreased to ~2.5 minutes -- a 13.6x faster
[ 1002.992533] mpt3sas version 13.100.00.00 loaded
...
[ 1151.978831] scsi 11:0:177:0: qdepth(16), tagged(1), simple(0),
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Back to the commit discussion.. on the ses_get_power_status() call
introduced in ses_enclosure_data_process(): impact of removing it.
That may possibly be in place to initialize the power status value
on device probe. However, those 2 functions available to retrieve
that value _do_ automatically refresh/update it. So the potential
benefit would be a direct access of the 'power_status' field which
does not use the callbacks...
But the only reader of 'struct enclosure_component::power_status'
is the get_component_power_status() callback for sysfs attribute,
and it _does_ check for and call the .get_power_status callback,
(which indeed is defined and implemented by that commit), so the
power status value is, again, automatically updated.
So, the remaining potential for a direct/non-callback access to
the power_status attribute would be out-of-tree modules -- well,
for those, if they are for whatever reason interested in values
that are set during device probe and not up-to-date by the time
they need it.. well, that would be curious.
Well, to handle that more properly, set the initial power state
value to '-1' (i.e., uninitialized) instead of '1' (power 'on'),
and check for it in that callback which may do an direct access
to the field value _if_ a callback function is not defined.
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Fixes: 08024885a2 ("ses: Add power_status to SES device slot")
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cathy Avery