Commit Graph

55 Commits

Author SHA1 Message Date
Kashyap D Desai
e315cf4dc4 Problem statement:
Due to hardware errata in Aero controllers, reads to certain
fusion registers could intermittently return all zeroes.
This behavior is transient in nature and subsequent reads will return
valid value.

Fix:
For Aero controllers, any read will retry the read operations
from certain registers for maximum three times, if read returns zero.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-26 10:47:52 +00:00
Kashyap D Desai
b518670c21 This patch will add support for 32 bit atomic request descriptor for Aero adapters.
For Aero adapters-
1. Driver will use 32 bit atomic descriptor to fire IOs and DCMDs.
2. Driver will use 64 bit request descriptor to fire IOC INIT.
3. If Aero firmware supports 32 bit atomic descriptor, then only driver will use it
otherwise driver will use 64 bit request descriptor.

For rest of adapters(Ventura, Invader and Thunderbolt), driver will use 64 bit request
descriptors only.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-26 10:47:08 +00:00
Kashyap D Desai
2909aab4cf This patch will add support for latest generation MegaRAID adapters- Aero(39xx).
Driver will throw a warning message when a Configurable secure type controller is
encountered.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-26 10:46:23 +00:00
Kashyap D Desai
56d91e4964 This patch will increase debug level as current logging level has
very minimal prints and even few important messages will not get logged.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:05:49 +00:00
Kashyap D Desai
e80341d50f Change IOC INIT wait time to 180 secs to keep it inline with timeout
used by internal DCMDs.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:05:01 +00:00
Kashyap D Desai
3d27317677 This patch will add support for NVME PRPs creation by driver for fastpath
capable IOs. NVME specification supports specific type of scatter gather list
called as PRP (Physical Region Page) for IO data buffers. Since NVME drive is
connected behind SAS3.5 tri-mode adapter, MegaRAID driver/firmware has to convert
OS SGLs in native NVMe PRP format. For IOs sent to firmware, MegaRAID firmware
does this job of OS SGLs to PRP translation and send PRPs to backend NVME device.
For fastpath IOs, driver will do this OS SGLs to PRP translation.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:04:16 +00:00
Kashyap D Desai
79b4460b0f This patch will add support for new DCMD to get PD information and a single data structure
to specify LD and JBOD.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:03:28 +00:00
Kashyap D Desai
2a1d3bcde8 To improve RAID 1/10 Write performance, OS drivers need to issue the
required Write IOs as Fast Path IOs (after the appropriate checks
allowing Fast Path to be used) to the appropriate physical drives
(translated from the OS logical IO) and wait for all Write IOs to complete.

Design: A write IO on RAID volume will be examined if it can be sent in
Fast Path based on IO size and starting LBA and ending LBA falling on to
a Physical Drive boundary. If the underlying RAID volume is a RAID 1/10,
driver issues two fast path write IOs one for each corresponding physical
drive after computing the corresponding start LBA for each physical drive.
Both write IOs will have the same payload and are posted to HW such that
replies land in the same reply queue.

If there are no resources available for sending two IOs, driver will send
the original IO from upper layer to RAID volume through the Firmware.

When both IOs are completed by HW, the resources will be released
and SCSI IO completion handler will be called.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:02:44 +00:00
Kashyap D Desai
821df4b93e Detect sequential Write IOs and pass the hint that it is part of sequential
stream to help HBA Firmware do the Full Stripe Writes. For read IOs on
certain RAID volumes like Read Ahead volumes,this will help driver to
send it to Firmware even if the IOs can potentially be sent to
hardware directly (called fast path) bypassing firmware.

Design: 8 streams are maintained per RAID volume as per the combined
firmware/driver design. When there is no stream detected the LRU stream
is used for next potential stream and LRU/MRU map is updated to make this
as MRU stream. Every time a stream is detected the MRU map
is updated to make the current stream as MRU stream.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:01:49 +00:00
Kashyap D Desai
c376f8641e This patch will add new interface to support more than 256 JBODs.
Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:00:45 +00:00
Kashyap D Desai
503c4f8d7f This patch will add support for divert bitmap in RAID map. Divert bitmap is supported for
SAS3.5 adapters only.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 08:00:01 +00:00
Kashyap D Desai
4ad8357607 This patch will add support for new Dynamic RaidMap to have different sizes
for different number of supported VDs for SAS3.5 MegaRAID adapters.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 07:59:09 +00:00
Kashyap D Desai
7aade8bfb8 This patch will add support for next generation(SAS3.5) of Tri mode(SAS, SATA, NVMe)
MegaRAID adapters.

Submitted by: Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:  Kashyap Desai <Kashyap.Desai@broadcom.com>
Approved by:  ken
MFC after:  3 days
Sponsored by:   Broadcom Inc
2018-12-14 07:57:00 +00:00
Pedro F. Giffuni
ac2fffa4b7 Revert r327828, r327949, r327953, r328016-r328026, r328041:
Uses of mallocarray(9).

The use of mallocarray(9) has rocketed the required swap to build FreeBSD.
This is likely caused by the allocation size attributes which put extra pressure
on the compiler.

Given that most of these checks are superfluous we have to choose better
where to use mallocarray(9). We still have more uses of mallocarray(9) but
hopefully this is enough to bring swap usage to a reasonable level.

Reported by:	wosch
PR:		225197
2018-01-21 15:42:36 +00:00
Pedro F. Giffuni
26c1d774b5 dev: make some use of mallocarray(9).
Focus on code where we are doing multiplications within malloc(9). None of
these is likely to overflow, however the change is still useful as some
static checkers can benefit from the allocation attributes we use for
mallocarray.

This initial sweep only covers malloc(9) calls with M_NOWAIT. No good
reason but I started doing the changes before r327796 and at that time it
was convenient to make sure the sorrounding code could handle NULL values.
2018-01-13 22:30:30 +00:00
Kashyap D Desai
2d53b48503 This patch will add code to refire IOCTL commands after OCR.
Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 13:04:40 +00:00
Kashyap D Desai
d993dd831d This patch will unblock SYNCHRONIZE_CACHE command to firmware, i.e. don't block the SYNCHRONIZE_CACHE command at driver instead of
passing it to firmware for all Gen3 controllers.
For Thunderbolt controller, keep the legacy behavior i.e. return the SYNCHRONIZE_CACHE command with success status from driver itself.

There is Sysctl parameter 'block_sync_cache' is provided to enable customers either to block/unblock these commands to facilitate
legacy behavior if there is a compatibility issue. Default value for module parameter is to unblock this command.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 13:03:43 +00:00
Kashyap D Desai
85c0a961fa Wait for AEN task to be completed(if in queue) before resetting the controller
and return without processing event in AEN thread, if controller reset is in progress.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 13:02:48 +00:00
Kashyap D Desai
8bb601ac8a This patch will add task management support in driver. Below is high level description:
If a SCSI IO times out, then before initiating OCR, now the driver will try to send a
target reset to the particular target for which the IO is timed out. If that also fails,
then the driver will initiate OCR.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 13:01:31 +00:00
Kashyap D Desai
e2e8afb12c Process outstanding reply descriptors from all the reply descriptor post queues before initiating OCR.
Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 12:59:38 +00:00
Kashyap D Desai
c2a20ff95a Clean up reference to AEN command if abort AEN is succesful as the command is aborted.
Did the same by setting sc->aen_cmd = NULL when aborting AEN is successful.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 12:58:28 +00:00
Kashyap D Desai
8bc320add0 Update controller properties(read OCR capability bit) when MR_EVT_CTRL_PROP_CHANGED recieved.
Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 12:56:53 +00:00
Kashyap D Desai
808517a4f9 Add sanity check in IO and IOCTL path not to process command further if controller is in
HW_CRITICAL_ERROR.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 12:55:01 +00:00
Kashyap D Desai
f9c630813e Use a variable to indicate Gen3 controllers and remove all PCI ids based
checks used for gen3 controllers.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 12:53:05 +00:00
Kashyap D Desai
731b75614d Problem statement:
MFI linked list in megaraid_sas driver is used for 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 frames 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.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   Broadcom Limited/AVAGO Technologies
2016-11-29 12:49:20 +00:00
Kashyap D Desai
8cd174a463 Added support for Avago/Broadcom Cutlass(12 Gbps- 16 port count) controllers.
Submitted by:   Sumit Saxena <Sumit.Saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   AVAGO/BROADCOM Limited
2016-06-02 12:26:55 +00:00
Kashyap D Desai
4bb0a4f048 Following bugs fixed as part of this patch:
.Kernel panic while collecting kdump (reported by Doug A.)
.NULL pointer dereference at sertain places
.Removed dead codes

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   AVAGO Technologies
2016-05-13 12:21:50 +00:00
Kashyap D Desai
c620f351de Added supprot for Avago Intruder controller.
Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   AVAGO Technologies
2016-05-13 12:18:12 +00:00
Kashyap D Desai
8071588d7a Implemented interrupt Config Hook in mrsas(4) to defer some of the tasks, like:
riegistering AEN, creating cdev.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   AVAGO Technologies
2016-05-13 12:15:20 +00:00
Kashyap D Desai
3a3fc6cba6 This patch implements driver support for 1MB IO size.
NOTE:
The FreeBSD system currently restricts the MAX IO size to MAXPHYS which
in turn is 128KB. We tested the 1MB IO by converting the MAXPHYS to 1MB.

Following is the mail reference:
http://lists.freebsd.org/pipermail/freebsd-scsi/2015-January/006568.html

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   AVAGO Technologies
2016-05-13 12:12:09 +00:00
Kashyap D Desai
a688fcd018 Similar to RAID map for Logical Drives, now JBOD map has been introduced for
JBODs. Driver has to sync the JBOD map with firmware and use sequence number
as a reference for JBOD FastPath I/O's.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   AVAGO Technologies
2016-05-13 12:05:02 +00:00
Kashyap D Desai
f0c7594bf3 There was no ERROR handling for firmware command TIMEOUT. This patch
takes care of any firmware command timeout scenarios by initiating OCR.

Submitted by:   Sumit Saxena <sumit.saxena@broadcom.com>
Reviewed by:    Kashyap Desai <Kashyap.Desai@broadcom.com>
MFC after:  3 days
Sponsored by:   AVAGO Technologies
2016-05-13 12:00:46 +00:00
Pedro F. Giffuni
453130d9bf sys/dev: minor spelling fixes.
Most affect comments, very few have user-visible effects.
2016-05-03 03:41:25 +00:00
Steven Hartland
5bae00d6b4 Fix NULL pointer dereferences
Fix NULL pointer dereferences identified as V522 by PVS-Studio.

MFC after:	1 week
Sponsored by:	Multiplay
2016-02-25 02:46:47 +00:00
Justin Hibbits
43cd61606b Replace several bus_alloc_resource() calls using default arguments with bus_alloc_resource_any()
Since these calls only use default arguments, bus_alloc_resource_any() is the
right call.

Differential Revision: https://reviews.freebsd.org/D5306
2016-02-19 03:37:56 +00:00
Kashyap D Desai
2f2163ab40 Counter part of mfi driver commit in mrsas
Switch from make_dev_alias to make_dev_alias_p since make_dev_alias_p can
gracefully fail if the /dev/megaraid_sas_ioctl_node symlink already exists.
This can happen if mfi(4) and mrsas(4) are both attached to cards and
providing Linux emulation support.  Let the first one win.  An equivalent
change has been done in mfi(4).  Extra credit would be to pass the
Linux emulation call to the other driver when appropriate.  This will
probably be a rare case and the user can manually change where the symlink
points to.

MFC after:  3 days
2015-06-26 12:00:51 +00:00
Kashyap D Desai
5b2490f890 Kernel panic may be observed by user, if MR controller is under Chip reset (OCR)
and there are some pending IOs at the time of OCR. This is mainly because of
recursive mutext in OCR and IO completion function call. Generic IO completion (from ISR) needs
sim_lock to be held before it calls completion to CAM (xpt_done), but in case of OCR path mrsas_ocr thread
itself take sim_lock, so this condition is now handled in this patch.

MFC after:  3 days
2015-06-26 11:58:42 +00:00
Kashyap D Desai
dbcc81dfdc Corrected indentation on conflicted source files.
Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2015-05-06 10:46:28 +00:00
Kashyap D Desai
ecea5be464 1. All LSI namings are converted to AVAGO Tech.
2. Fix in AEN path(suggested by John Baldwin).
3. Fix IOCTL path w.r.t Sense key handling

Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2015-05-06 10:45:13 +00:00
Kashyap D Desai
2f863eb8d8 Bug fixes found internally as detailed below:
1. While disabling interrupt the FW disables interrupts for only 16 vectors.
In case of Invader which supports 96 MSI-x vectors, some spurious interrupts
may come on other vectors even after interrupt disable. So, driver uses a flag
and ignores the spurious interrupts.
2. Reply queue depth is made double the number of commands supported by FW.
3. Misplaced interrupt enable code is now moved down in the OCR path.
4. Updated error handling code in OCR path.
5. Removed un-necessary print.

Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2015-05-06 10:44:08 +00:00
Kashyap D Desai
daeed97380 Driver calls mrsas_complete_cmd() to call mrsas_wakeup() for each MFI frame that was
issued through the ioctl() interface prior to the kill adapter. This ensures
userspace ioctl() system calls issued just before a kill adapter don't get stuck in
wait state and IOCTLs are returned to application.

Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2015-05-06 10:43:19 +00:00
Kashyap D Desai
af51c29f66 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.

Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2015-05-06 10:42:44 +00:00
Kashyap D Desai
16dc2814ee 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.

Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2015-05-06 10:41:27 +00:00
Kashyap D Desai
77cf7df804 Now Driver expose Secure Jbod Support via driver_operations in MFI INIT Frame.
FW expose Secure Jbod support via Controller properity.

Firmware expect IOs to be received from different IO path than
conventional fast path queue, in case of SED drives.

To have Secure jbod support user need driver and firmware support.

Reviewed by:    ambrisko
MFC after:  2 weeks
Sponsored by:   AVAGO Technologies
2015-05-06 10:36:53 +00:00
Kashyap D Desai
5844115e3a This patch adds the feature to provide PCI information via IOCTL query.
Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2015-05-06 10:32:27 +00:00
John Baldwin
7fc5f32950 Use struct thread directly instead of d_thread_t. This driver is not
likely to be backported to 4.x.

Reviewed by:	kadesai
2015-01-06 15:41:23 +00:00
Hans Petter Selasky
f0188618f2 Fix multiple incorrect SYSCTL arguments in the kernel:
- Wrong integer type was specified.

- Wrong or missing "access" specifier. The "access" specifier
sometimes included the SYSCTL type, which it should not, except for
procedural SYSCTL nodes.

- Logical OR where binary OR was expected.

- Properly assert the "access" argument passed to all SYSCTL macros,
using the CTASSERT macro. This applies to both static- and dynamically
created SYSCTLs.

- Properly assert the the data type for both static and dynamic
SYSCTLs. In the case of static SYSCTLs we only assert that the data
pointed to by the SYSCTL data pointer has the correct size, hence
there is no easy way to assert types in the C language outside a
C-function.

- Rewrote some code which doesn't pass a constant "access" specifier
when creating dynamic SYSCTL nodes, which is now a requirement.

- Updated "EXAMPLES" section in SYSCTL manual page.

MFC after:	3 days
Sponsored by:	Mellanox Technologies
2014-10-21 07:31:21 +00:00
Kashyap D Desai
f5fb223710 Fix for build issue on i386.xen and amd64.xen.
This is a duplicate variable reference in mrsas, so now this patch isolate atomic_ variable and relavent
function call using prefix mrsas_xx.

Issue was introduced in r272737.

MFC after:	2 weeks
Sponsored by:	Avago Technology
2014-10-13 15:33:27 +00:00
Kashyap D Desai
8e72737119 No logical code change in this pathc.
Only Style 9 changes for mrsas driver.

Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2014-10-08 10:14:37 +00:00
Kashyap D Desai
839ee02531 In the passthru IOCTL path, the mfi command pool was freely accessible N times
where as there are limited number(32) of mfi commands in the pool.
The mfi command pool is now restricted to 27 simultaneous accesses by using
a counting semaphore while calling the passthru function.

In the mrsas_cam.c source file there was a same function name mrsas_poll(),
which was same as the mrsas_poll() implemented in the mrsas.c file for the
polling interface.
To clearly distinguish the functionality by usage we have renamed the former
as mrsas_cam_poll().

In the passthru function let's say it has got an mfi command from the pool
but it has failed in one of the DMA function call which will lead to leak
an mfi command because in the ERROR case it directly returns and not freeing up
the occupied mfi command.

Reviewed by:	ambrisko
MFC after:	2 weeks
Sponsored by:	AVAGO Technologies
2014-10-08 09:37:47 +00:00