There was an issue reported by Lucz Geza on Dell Perc 6i. As per issue
reported, megaraid_sas driver goes into an infinite error reporting loop
as soon as there is a change in the status of one of the
arrays (degrade, resync online etc ).  Below are the error logs reported
continuously-

Jun 25 08:49:30 ns8 kernel: [  757.757017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.778017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.799017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.820018] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.841018] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115

This issue is very much specific to controllers which do not support
DCMD- MR_DCMD_PD_LIST_QUERY.  In case of any hotplugging/rescanning of
drives, AEN thread will be scheduled by driver and fire DCMD-
MR_DCMD_PD_LIST_QUERY and if this DCMD is failed then driver will fail
this event processing and will not go ahead for further events. This
will cause infinite loop of same event getting retried infinitely and
causing above mentioned logs.

Fix for this problem is: not to fire DCMD MR_DCMD_PD_LIST_QUERY for
controllers which do not support it and send DCMD SUCCESS status to AEN
function so that it can go ahead with other event processing.
Reported-by: NLucz Geza <geza@lucz.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NSumit Saxena <sumit.saxena@broadcom.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

I actually read the error messages in my logs, and successful
initialization is not an error.

Arguably these log lines could be deleted entirely.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Reviewed-by: NHannes Reinicke <hare@suse.de>
Acked-by: NSumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch will do code optmization for task management functions.
Below are key changes:

1. Remove reset_device hook as it was not being used and driver was
setting this to NULL.

2. Create wrapper functions for task abort and target reset and inside
   these functions adapter specific calls be made. e.g. fusion adapters
   support task abort and target reset so task abort and target reset
   should be issued to fusion adapters only and for MFI adapters, print
   a message saying feature not supported.
Signed-off-by: NSumit Saxena <sumit.saxena@broadcom.com>
Reviewed-by: NHannes Reinicke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch will reduce memory footprints of megaraid_sas driver when
booted in kdump mode.  Driver will not allocate memory for optional and
perfromance oriented features.  Below are key changes done in
megaraid_sas driver to do this:

1. Limit Controller's queue depth to 100 in kdump mode.

2. Do not allocate memory for system info buffer and PD info buffer.

3. Disable performance oriented features e.g. Disable RDPQ mode, disable
   dual queue depth, restrict to single MSI-x vector.
Signed-off-by: NSumit Saxena <sumit.saxena@broadcom.com>
Reviewed-by: NHannes Reinicke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

gcc-6 found a dubious indentation in the megasas_mgmt_fw_ioctl
function:

drivers/scsi/megaraid/megaraid_sas_base.c: In function 'megasas_mgmt_fw_ioctl':
drivers/scsi/megaraid/megaraid_sas_base.c:6658:4: warning: statement is indented as if it were guarded by... [-Wmisleading-indentation]
    kbuff_arr[i] = NULL;
    ^~~~~~~~~
drivers/scsi/megaraid/megaraid_sas_base.c:6653:3: note: ...this 'if' clause, but it is not
   if (kbuff_arr[i])
   ^~

The code is actually correct, as there is no downside in clearing a NULL
pointer again.

This clarifies the code and avoids the warning by adding extra curly
braces.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: 90dc9d98 ("megaraid_sas : MFI MPT linked list corruption fix")
Reviewed-by: NHannes Reinecke <hare@suse.com>
Acked-by: NSumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

There are few MFI adapters which do not support MR_DCMD_PD_LIST_QUERY so
if MFI adapters fail this DCMD, it should not be considered as FATAL and
driver should not issue kill adapter and set per controller's instance
variable- pd_list_not_supported so that same variable can be used inside
functions- slave_alloc and slave_configure to allow firmware scan.

Killing adapter because of DCMD failure when this DCMD is not supported
causes driver's probe getting failed. This issue got introduced by
commit 6d40afbc ("megaraid_sas: MFI IO timeout handling").

Killing adapter in case of this DCMD failure should be limited to Fusion
adapters only. Per controller's instance variable allow_fw_scan is
removed as pd_list_not_supported better reflect the purpose.

Fixes: 6d40afbcSigned-off-by: NSumit Saxena <sumit.saxena@broadcom.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NHannes Reinicke <hare@suse.de>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

A barrier should be added to ensure proper ordering of memory mapped
writes.
Signed-off-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NKashyap Desai <kashyap.desai@broadcom.com>
Acked-by: NKashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Inside compat IOCTL hook of driver, driver was using wrong address of
ioc->frame.raw which leads sense_ioc_ptr to be calculated wrongly and
failing IOCTL.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Driver assumes that VFs always have peers present whenever they have
same LD IDs. But this is not the case.  This patch handles the above
mentioned by explicitly checking for a peer before making HA/non-HA path
decision.
Signed-off-by: NUday Lingala <uday.lingala@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The pd_seq_sync pointer can't be NULL, we have to check its entries
instead.
Signed-off-by: NMaurizio Lombardi <mlombard@redhat.com>
Acked-by: NSumit Saxena <sumit.saxena@broadcom.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch will introduce module-parameter for SCSI command timeout
value and fix setting of resetwaittime beyond a value.
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Optimized MFI adapters' OCR path, particularly
megasas_wait_for_outstanding() function.
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Make instance->adprecovery variable atomic and removes hba_lock spinlock
while accessing instance->adprecovery.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

1. For iMR controllers, firmware will report two queue depths:

   - Controller-wide queue depth
   - LDIO queue depth (240)

Controller-wide queue depth will be greater among the two. Using this
new feature, iMR can provide larger Queue depth(QD) for JBOD and limited
QD for Virtual Disk(VD).

2. megaraid_sas driver will throttle read/write LDIOs based on "LDIO
Queue Depth".

3. Dual queue depth can be enabled/disabled via module parameter. It is
enabled by default if the firmware supports it. Only specific firmware
builds will enable the feature.

4. Added sysfs parameter "ldio_outstanding" which permits querying the
number of outstanding LDIO requests at runtime.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

build_and_issue_cmd should return SCSI_MLQUEUE_HOST_BUSY for a few error
cases instead of returning 1.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch will create a reply queue pool for each MSI-X index and will
provide an array of base addresses instead of the single address of
legacy mode. Using this new interface the driver can support higher
queue depths through scattered DMA pools.

If array mode is not supported driver will fall back to the legacy
method of reply pool allocation. This limits controller queue depth to
1K max. To enable a queue depth of more than 1K driver requires firmware
to support array mode and scratch_pad3 will provide the new queue depth
value.

When RDPQ is used, downgrading to an older firmware release should not
be permitted. This may cause firmware fault and is not supported.
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch will update device Queue depth based on interface type(SAS,
SATA..) for sysPDs.  For Virtual disks(VDs), there will be no change in
queue depth (will remain 256).  To fetch interface type (SAS or SATA or
FC..) of syspD, driver will send DCMD MR_DCMD_PD_GET_INFO.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch adds task management for SCSI commands. Added functions are
task abort and target reset.

1. Currently, megaraid_sas driver performs controller reset when any IO
times out.  With task management support added, task abort and target
reset will be tried to recover timed out IO. If task management fails,
then controller reset will be performaned. If the task management
request times out, fail the request and escalate to the next
level (controller reset).

2. mr_device_priv_data will be allocated for all generations of
controller, but is_tm_capable flag will never be set for
controllers (prior to Invader series) as firmware support is not
available for task management.

3. Task management capable firmware will set is_tm_capable flag in
firmware API.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch will do proper error handling for DCMD timeout failure cases
for Fusion adapters:

1. For MFI adapters, in case of DCMD timeout (DCMD which must return
SUCCESS) driver will call kill adapter.

2. What action needs to be taken in case of DCMD timeout is decided by
function dcmd_timeout_ocr_possible().  DCMD timeout causing OCR is
applicable to the following commands:

	MR_DCMD_PD_LIST_QUERY
	MR_DCMD_LD_GET_LIST
	MR_DCMD_LD_LIST_QUERY
	MR_DCMD_CTRL_SET_CRASH_DUMP_PARAMS
	MR_DCMD_SYSTEM_PD_MAP_GET_INFO
	MR_DCMD_LD_MAP_GET_INFO

3. If DCMD fails from driver init path there are certain DCMDs which
must return SUCCESS. If those DCMDs fail, driver bails out. For optional
DCMDs like pd_info etc., driver continues without executing certain
functionality.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch will do synhronization between OCR function and AEN function
using "reset_mutex" lock.  reset_mutex will be acquired only in the
first half of the AEN function which issues a DCMD. Second half of the
function which calls SCSI API (scsi_add_device/scsi_remove_device)
should be out of reset_mutex to avoid deadlock between scsi_eh thread
and driver.

During chip reset (inside OCR function), there should not be any PCI
access and AEN function (which is called in delayed context) may be
firing DCMDs (doing PCI writes) when chip reset is happening in parallel
which will cause FW fault. This patch will solve the problem by making
AEN thread and OCR thread mutually exclusive.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This patch changes the !blk-mq path to the same defaults as the blk-mq
I/O path by always enabling block tagging, and always using host wide
tags.  We've had blk-mq available for a few releases so bugs with
this mode should have been ironed out, and this ensures we get better
coverage of over tagging setup over different configs.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

The DELL PERC5 controller firmware does not list tape drives in response
to MR_DCMD_PD_LIST_QUERY. This causes tape drives not be exposed to the
OS when connected to a PERC5 controller.

This patch permits detection of tape drives connected to a PERC5
controller by exposing non-TYPE_DISK devices unconditionally.
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This is an issue on SMAP enabled CPUs and 32 bit apps running on 64 bit
OS. Do not access user memory from kernel code. The SMAP bit restricts
accessing user memory from kernel code.

Cc: <stable@vger.kernel.org>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

It may happen (kdump), that an interrupt is invoked just after the
setup_irqs function was called but before the tasklet was initialised.
At this phase the hw ints should have been disabled, but for unknown
reason this mechanism seems to not work properly.

From: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Do not use PAGE_SIZE marco to calculate max_sectors per I/O
request. Driver code assumes PAGE_SIZE will be always 4096 which can
lead to wrongly calculated value if PAGE_SIZE is not 4096. This issue
was reported in Ubuntu Bugzilla Bug #1475166.

Cc: <stable@vger.kernel.org>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Remove PCI id based checks and use instance->ctrl_context to decide
whether controller is MFI-based or a Fusion adapter. Additionally,
Fusion adapters are divided into two categories: Thunderbolt and
Invader.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Expose non-disk (TAPE drive, CD-ROM) unconditionally.

Cc: <stable@vger.kernel.org>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Some of these code changes were proposed by David Binderman.

Removed redudant check of requestorId. Redundant condition:
instance.requestorId. Check for plasma firmware 1.11 are now
restructured to support only specific device id.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Print firmware events in human-readable form. This will help users track
any critical firmware events without special application support.

Sample syslogd output:

megaraid_sas 0000:02:00.0: 8619 (491648347s/0x0020/WARN) - Controller temperature threshold exceeded. This may indicate inadequate system cooling. Switching to low performance mode.

The format of logged events is:

"<pci_dev_id>: <sequence_number> (<timestamp>/<locale>/<class>) - <description>"
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Implemented JBOD map which will provide quick access for JBOD path and
also provide sequence number.  This will help hardware to fail command
to the FW in case of any sequence mismatch.

Fast Path I/O for JBOD will refer JBOD map (which has sequence number
per JBOD device) instead of RAID map.  Previously, the driver used RAID
map to get device handle for fast path I/O and this not have sequence
number information. Now, driver will use JBOD map instead.  As part of
error handling, if JBOD map is failed/not supported by firmware, driver
will continue using legacy behavior.

Now there will be three IO paths for JBOD (syspd):

 - JBOD map with sequence number (Fast Path)
 - RAID map without sequence number (Fast Path)
 - FW path via h/w exception queue deliberately setup devhandle
   0xFFFF (FW path).

Relevant data structures:

 - Driver send new DCMD MR_DCMD_SYSTEM_PD_MAP_GET_INFO for this purpose.
 - struct MR_PD_CFG_SEQ- This structure represent map of single physical
   device.
 - struct MR_PD_CFG_SEQ_NUM_SYNC- This structure represent whole JBOD
   map in general(size, count of sysPDs configured, struct MR_PD_CFG_SEQ
   of syspD with 0 index).
 - JBOD sequence map size is: sizeof(struct MR_PD_CFG_SEQ_NUM_SYNC)
   + (sizeof(struct MR_PD_CFG_SEQ) * (MAX_PHYSICAL_DEVICES - 1)) which
   is allocated while setting up JBOD map at driver load time.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NMartin Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: NMartin Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Fix whitespace and indentation errors.  No code change.

[jejb: checkpatch fixes]
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Acked-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Use dev_printk() when possible to make messages more useful.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Acked-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

This fixes a regression caused by commit
d3557fc8 megaraid_sas : Add separate function
for setting up IRQs This makes boot end with 'root does not exist' message on
certain adapters.

The bug is that the driver does not setup ints for cards without msi-x
support.  This patch fixes it, in addition to that it moves tasklet
initialisation before enable_intr, otherwise a kernel panic may occur, when an
interrupt arrives before the tasklet is ready.
Signed-off-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

megaraid_sas : Modify return value of megasas_issue_blocked_cmd() and wait_and_poll() to consider command status returned by firmware

This patch is rebased on top of recently sent 18 patches(submitted by me) for
megaraid_sas driver.

Change the return value of wait_and_poll() and megsas_issue_blocked_cmd()
based on MFI_STAT returned by firmware for that command. Earlier driver always
send return type based on command completion (but never check MFI_STAT_OK for
that command), so even if command is failed by firmware still driver will
return SUCCESS status from these functions wait_and_poll() and
megsas_issue_blocked_cmd() and if caller of these functions does not check
command status (MFI_STAT), then it may endup using invalid data returned in
DMA buffers(one of the example is megasas_ld_list_query DCMD). Best thing to
avoid this type of issue is do error handling and set proper return type from
caller function wait_and_poll() and megsas_issue_blocked_cmd().

The change proposed in this patch will fix the regression introduced in patch-
"90dc9d98 megaraid_sas : MFI MPT linked list corruption fix" inside function
megasas_ld_list_query().  Prior to this MFI MPT linked list corruption fix
patch, megasas_ld_list_query() function used to check DCMD status(returned by
firmware) but with this linked list corruption fix patch, DCMD status will not
be checked inside function megasas_ld_list_query() and introduced this issue
of wrong data being used by function megasas_ld_list_query().

Cc: <stable@vger.kernel.org>
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>