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>

Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.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>

This patch will add capability in driver to tell firmware that it can
throttle IOs in case controller's queue depth is downgraded post OFU
(online firmware upgrade). This feature will ensure firmware can be
downgraded from higher queue depth to lower queue depth without needing
system reboot. Added throttling code in IO path of driver, in case OS
tries to send more IOs than post OFU firmware's queue depth.
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>

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>

Firmware will fill out per-LD data to tell driver whether a particular
LD supports region lock bypass. If yes, then driver will send non-FP
LDIO to region lock bypass FIFO. With this change in driver, firmware
will optimize certain code to improve performance.
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>

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>

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>

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>

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>

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>

Driver will expose max sge = 256 (earlier it was 64) if firmware
supports extended IO size (1M).
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>

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>

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>

This adds endianness annotations to all data structures, and a few
variables directly referencing them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

This patch will add support for Single Server High Availability(SSHA) cluster
support.  Here is the short decsription of changes done to add support for
SSHA-

1) Host will send system's Unique ID based on DMI_PRODUCT_UUID to firmware.
2) Toggle the devhandle in LDIO path for Remote LDs.
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

This patch will upgrade the driver version and add back the release date and
sysfs hook for the same.  Some internal applications uses sysfs parameter for
release date, so they were broken because of removal of release date from
sysfs.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

megaraid_sas driver will use block layer provided tag for indexing internal
MPT frames to get any unique MPT frame tied with tag.  Each IO request
submitted from SCSI mid layer will get associated MPT frame from MPT framepool
(retrieved and return back using spinlock inside megaraid_sas driver's
submission/completion call back). Getting MPT frame from MPT Frame pool is
very expensive operation because of associated spin lock operation (spinlock
overhead increase on multi NUMA node). This type of locking in driver is very
expensive call considering each IO request need - Acquire and Release of the
same lock.

With this support, in IO path driver will directly provide the unique command
index(which is based on block layer tag) and will get the MPT frame tied to
the tag and this way driver can get rid off lock, which synchronizes the
access to MPT frame pool while fetching and returning MPT frame from the pool.

This support in driver provides siginificant performance improvement(on multi
NUMA node system)on latest upstream with SCSI.MQ as well as on existing linux
distributions.

Here is the data for test executed at Avago-
- IO Tool- FIO
- 4 Socket SMC server. (4 NUMA node server)
- 12 SSDs in JBOD mode .
- 4K Rand READ, QD=32
- SCSI MQ x86_64 (Latest Upstream kernel)
- upto 300% Performance Improvement.

If IOs are running on single Node, perfromance gain is less, but as soon as
increase number of nodes, performance improvement is significant. IOs running
on all 4 NUMA nodes, with this patch applied IOPs observed was 1170K vs 344K
IOPs seen without this patch.

Logically, there are two parts of this patch- 1) Block layer tag support 2)
changes in calling convention of return_cmd.  part 2 will revert the changes
done by patch- 90dc9d98 megaraid_sas : MFI MPT linked list corruption fix
because changes done in part 1 has fixed the problem of MFI MPT linked list
corruption. part 2 is very much dependent on part 1, so we decided to have
single patch for these two logical changes.

[jejb: remove chatty printk pointed out by hch]
Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Signed-off-by: NKashyap Desai <kashyap.desai@avagotech.com>
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

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>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Update megaraid_sas driver version.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

1) For fusion adapters, limit reserved frames for non SCSI commands to 8
   (3 for parallel IOCTLs + 5 for driver's internal DCMDs).
   Earlier reserved commands for non SCSI IO frames was set to 32, so with
   this implementation, increased per controller "can_queue".
   Behavior of MFI controllers will remain unchanged.

2) Optimize the code related to per controller's 'can_queue' setting.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NChaitra Basappa <chaitra.basappa@avagotech.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch adds support for Secure Encrypting Drives (SED) in JBOD mode:

1) If the firmware supports SED JBOD, all non read/write commands to JBODs
   will be sent via firmware path, and read/write commands to JBODs will
   be sent via fastpath.
2) If the firmware does not support SED JBOD, driver will fall back to the
   old design, i.e. send all JBOD I/O via fastpath.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: NChaitra Basappa <chaitra.basappa@avagotech.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

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: 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: NChristoph Hellwig <hch@lst.de>

Update MAINTAINERS list and copyright information for megaraid_sas driver.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Update driver version and remove some meta data (release date and extended
version) about megaraid_sas driver.
Signed-off-by: NSumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Resending the patch. Addressed the review comments by Tomas Henzl.

Driver version upgrade patch.
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: NChristoph Hellwig <hch@lst.de>

Resending the patch. Addressed the review comments from Tomas Henzl.
Added comment for to-do work.

Problem statement:
MFI link list in megaraid_sas driver is used from mfi-mpt pass-through commands.
This list can be corrupted due to many possible race conditions in driver and
eventually we may see kernel panic.

One example -
MFI frame is freed from calling process as driver send command via polling method and interrupt
for that command comes after driver free mfi frame (actually even after some other context reuse
the mfi frame). When driver receive MPT frame in ISR, driver will be using the index of MFI and
access that MFI frame and finally in-used MFI frame’s list will be corrupted.

High level description of new solution -
Free MFI and MPT command from same context.
Free both the command either from process (from where mfi-mpt pass-through was called) or from
ISR context. Do not split freeing of MFI and MPT, because it creates the race condition which
will do MFI/MPT list corruption.

Renamed the cmd_pool_lock which is used in instance as well as fusion with below name.
mfi_pool_lock and mpt_pool_lock to add more code readability.
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: NChristoph Hellwig <hch@lst.de>

Resending the patch. Addressed the review comments from Tomas Henzl.

Current driver does fast path read load balancing between arm and mirror disk
for two Drive Raid-1 configuration only.

Now, Driver support fast path read load balancing for all (any number of disk) Raid-1 configuration.
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: NChristoph Hellwig <hch@lst.de>

Resending the patch. Addressed the review comments from Tomas Henzl.
reserved1 field(part of union) of Raid map struct was not required so it is removed.

Current MegaRAID firmware and hence the driver only supported 64VDs.
E.g: If the user wants to create more than 64VD on a controller,
    it is not possible on current firmware/driver.

New feature and requirement to support upto 256VD, firmware/driver/apps need changes.
In addition to that there must be a backward compatibility of the new driver with the
older firmware and vice versa.

RAID map is the interface between Driver and FW to fetch all required
fields(attributes) for each Virtual Drives.
In the earlier design driver was using the FW copy of RAID map where as
in the new design the Driver will keep the RAID map copy of its own; on which
it will operate for any raid map access in fast path.

Local driver raid map copy will provide ease of access through out the code
and provide generic interface for future FW raid map changes.

For the backward compatibility driver will notify FW that it supports 256VD
to the FW in driver capability field.
Based on the controller properly returned by the FW, the Driver will know
whether it supports 256VD or not and will copy the RAID map accordingly.

At any given time, driver will always have old or new Raid map.
So with this changes, driver can also work in host lock less mode. Please
see next patch which enable host lock less mode for megaraid_sas driver.
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: NChristoph Hellwig <hch@lst.de>