Commit Graph

369 Commits

Author SHA1 Message Date
Gregory Greenman
855f492f65 iwlwifi: mvm: rs: add rate scaling support for 160MHz channels
Expand TLC to support 160MHz channels. Full support for A-MSDU
case will be added separately.

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 01:19:22 +03:00
Ayala Beker
99980ecfff iwlwifi: mvm: fix RX mpdu status enum
FW sets status for each RX packet.
Enum in the driver doesn't match with FW definition - fix it.

Signed-off-by: Ayala Beker <ayala.beker@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 01:18:43 +03:00
Matti Gottlieb
ff7a68d0e7 iwlwifi: mvm: Do not open aggregations for null data packets
Currently we try to open an aggregation for every packet (given that one
is not already open).

This causes redundant overhead (addba/delba) for null data packets.

Do not open an aggregation for null data packets.

Signed-off-by: Matti Gottlieb <matti.gottlieb@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 01:18:06 +03:00
Sara Sharon
d7fdd0e528 iwlwifi: pcie: poll RFH for RX DMA stop
Somehow we ended up stopping RX using legacy RX registers
even for devices that support RFH. Fix it.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 01:16:08 +03:00
Luca Coelho
34777b0000 iwlwifi: mvm: remove unnecessary device conversion when reading the MCC
We convert the mvm device to a PCI device and then back again when
trying to find the handle for the device's ACPI data.  This is
unnecessary, so it can be removed.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 01:15:26 +03:00
Oren Givon
f24bbae565 iwlwifi: add new 8265
Add 6 new 8265 series PCI IDs:
  - (0x24FD, 0x1130)
  - (0x24FD, 0x0130)
  - (0x24FD, 0x0910)
  - (0x24FD, 0x0930)
  - (0x24FD, 0x0950)
  - (0x24FD, 0x0850)

CC: <stable@vger.kernel.org> [4.6+]
Signed-off-by: Oren Givon <oren.givon@intel.com>
Signed-off-by: David Spinadel <david.spinadel@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 01:08:56 +03:00
Oren Givon
4b79deece5 iwlwifi: add new 8260 PCI IDs
Add 3 new 8260 series PCI IDs:
  - (0x24F3, 0x10B0)
  - (0x24F3, 0xD0B0)
  - (0x24F3, 0xB0B0)

CC: <stable@vger.kernel.org> [4.1+]
Signed-off-by: Oren Givon <oren.givon@intel.com>
Signed-off-by: David Spinadel <david.spinadel@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 01:08:07 +03:00
Liad Kaufman
97d5be7e22 iwlwifi: mvm: support dqa-enable hcmd
Support sending the DQA-enablement HCMD to the FW when
working in DQA mode.

This HCMD will enable DQA-specific flows in the FW.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:49:21 +03:00
Liad Kaufman
28d0793ed2 iwlwifi: mvm: update aux queue in dqa mode
In DQA mode the AUX queue is mapped elsewhere than in non-
DQA mode. Update the code to reflect this.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:48:55 +03:00
Liad Kaufman
93f436e2c7 iwlwifi: mvm: set sta_id in SCD_QUEUE_CONFIG cmd
Set the correct sta_id in the SCD_QUEUE_CONFIG command sent
to the FW when enabling/disabling queues. This is needed in
DQA-mode to allow the FW to associate between queue and STA.

In case the queue isn't connected to a specific station but
rather is a static "generic" queue - the sta_id should be
set to 0x10 (max supported STA is 0x0f).

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:48:26 +03:00
Liad Kaufman
42db09c1b0 iwlwifi: mvm: support dqa queue sharing
Support DQA queue sharing when no free queue exists for
allocation to a STA that already exists. This means that
a single queue will serve more than a single TID (although
the RA will be the same for all TIDs served).

We try to choose the lowest AC possible, to ensure the
shared queues have the lowest possible combined AC
requirements. The queue to share is chosen only from the
same RA's DATA queues as follows (in descending priority):
 1. An AC_BE queue
 2. Same AC queue
 3. Highest AC queue that is lower than new AC
 4. Any existing AC (there always is at least 1 DATA queue)

If any aggregations existed for any of the TIDs of the
shared queue - they are stopped (the FW is notified), but
no delBA is sent.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:47:41 +03:00
Dan Carpenter
32afd15b0f iwlwifi: mvm: silence uninitialized variable warning
"max_amsdu_len" isn't set if kstrtouint() fails.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:37:21 +03:00
Dan Carpenter
bdbc58abe7 iwlwifi: mvm: remove an unused variable
We never initialize ampdu_status so it causes a static checker warning
when we pass it to iwl_mvm_pass_packet_to_mac80211().  Fortunately, it's
never used so we can just remove it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:35:11 +03:00
Luca Coelho
69e046423a iwlwifi: mvm: change scan timeout to a delayed work
Some transports may sleep when writing to registers, which is done
when calling iwl_force_nmi().  So we can't call iwl_force_nmi() in a
timer context.  To solve that, convert the scan timeout timer to a
delayed work.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:33:07 +03:00
Sara Sharon
f43495fd5e iwlwifi: mvm: fix possible division by zero
Theoretically we may get only one IRQ from OS, in which
case we will have only 1 queue even in MSIx mode.
This will cause division by zero in the indirection table
calculation.
We do not need send the command in that case, as there is
only one queue so all RX traffic will be directed to it
anyway. Bail out early if there is only one queue.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:33:06 +03:00
Sara Sharon
2047fa5401 iwlwifi: pcie: unify restock calls on init
Currently code calls restock for mq devices during the init
function, unlike sq where restock is called after init.
This causes an harmless but alarming deadlock warning from
lockdep, to fix this - unify the init code.
Rename the restock functions while at it.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:15:36 +03:00
Liad Kaufman
9794c64f30 iwlwifi: mvm: support dqa queue inactivation upon timeout
Support marking queues as inactive upon a timeout expiring,
and allow inactive queues to be re-assigned to other RA/TIDs
if no other queue is free.

This is done by keeping a timestamp of the latest frame TXed
for every RA/TID, and then going over the queues currently in
use when a new queue is needed, inactivating all those that
are inactive.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:14:27 +03:00
Johannes Berg
ca221c9b94 iwlwifi: change fw.mvm_fw to fw.type
Instead of explicitly indicating the difference between just
DVM and MVM with an mvm_fw boolean change this to fw.type to
be more extensible and easier to understand.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:08:21 +03:00
Johannes Berg
6d48fcd900 iwlwifi: remove useless enum values
Since the values of this enum are used only internally,
we can let the compiler number them.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-06 00:06:04 +03:00
Johannes Berg
58035432d6 iwlwifi: mvm: handle FRAME_RELEASE in MQ code
For some reason, the FRAME_RELEASE message handling for the
default queue ended up being in the only/default queue for
non-RSS devices; fix that and handle FRAME_RELEASE properly
on the default queue for RSS devices.

Fixes: 585a6fccf5 ("iwlwifi: mvm: infrastructure for frame-release message")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:46 +03:00
Andrei Otcheretianski
d3a108a48d iwlwifi: mvm: Support CSA countdown offloading
Add support CSA countdown offloading. When CSA starts, the driver
specifies the offsets to the eCSA and CSA IEs in the beacon template
command and the fw performs the countdown.
The fw notifies the driver when the channel switch flow
should be performed.
Beacon sent notifications are not used anymore.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:45 +03:00
Sara Sharon
ab2e696bd2 iwlwifi: pcie: make sure packet arrived to destined queue
Add a warning in case packet didn't end up in the HW
destined queue.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:44 +03:00
Sara Sharon
630443355a iwlwifi: pcie: allow more than one frame in RB for 9000 devices
We now have 9000 devices that support multiple frames in
a single RB. Enable it.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:43 +03:00
Sara Sharon
b0262f07f4 iwlwifi: pcie: set RB chunk size per bus
For 9000 devices we can have PCIe bus for discrete
devices and IOSF bus for integrated devices.
PCIe supports maximum transfer size of 128B while IOSF
bus supports maximum transfer size of 64B.
Configure RB size accordingly.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:42 +03:00
Sara Sharon
1316d5957b iwlwifi: pcie: workaround HW shadow registers bug
Integrated 9000 devices have a bug with shadow registers
value retention.
If driver writes RBD registers while MAC is asleep the
values are stored in shadow registers to be copied whenever
MAC wakes up.
However, in 9000 devices a MAC wakeup is not triggered
and when the bus powers down due to inactivity the shadow
values and dirty bits are lost.
Turn on the chicken-bits that cause MAC wakeup for RX-related
values as well when the device is in D0.
When the device is in low power mode turn the RX wakeup chicken
bits off since driver is idle and this W/A is not needed.
Remove previous W/A which was ineffective.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:42 +03:00
Liad Kaufman
a6f035a008 iwlwifi: mvm: free dqa queues on STA removal also in non-bss
Support queue removal in DQA mode in iwl_mvm_rm_sta() also when
the device isn't a STA connected to an AP.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:41 +03:00
Sara Sharon
fbe4112791 iwlwifi: mvm: update mpdu metadata API
rx_phy notification is no longer sent in devices with
multiple rx queues.
All the needed data is now set in the metadata - update
code accordingly to reflect all the features as in the
previous RX path.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:40 +03:00
Sara Sharon
6d99c88f60 iwlwifi: mvm: remove RX_PHY support for 9000 device
In multiple RX queues architecture, the RX_PHY notification
is no longer useful as it is received in the default queue
even for packets that are received on RSS queue, and cannot
be accessed without locking.
All the needed data is in the new RX packet metadata and
firmware will no longer send this notification for 9000
devices. Remove support of it.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:39 +03:00
Avraham Stern
c5241b0c8c iwlwifi: rename CAPA_P2P_STANDALONE_UAPSD to CAPA_P2P_SCM_UAPSD
Ucode capability bit 26 indicates support for UAPSD on P2P interface
even with a simultaneous BSS station interface, as long as both
interfaces are in the same binding. Change the name of the
capability bit to reflect that.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 18:09:23 +03:00
Johannes Berg
7bde4c6831 iwlwifi: mvm: fix comment indentation
Somehow we ended up without leading spaces here, fix that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 16:58:39 +03:00
Sara Sharon
e7e14089e9 iwlwifi: mvm: do not trust NSSN for amsdu sub-frames
We cannot trust NSSN for AMSDU sub-frames that are not the
last.
The reason is that NSSN advances on the first sub-frame,
and may cause the reorder buffer to advance before all the
sub-frames arrive.
Example:
Reorder buffer contains SN 0 & 2.
We receive AMSDU with SN 1 and NSSN for first sub frame 3.
The result us that driver releases SN 0,1, 2.
When sub-frame 1 arrives - reorder buffer is already ahead and
it will be dropped.
If the last sub-frame is not on this queue - we will get frame
release notification with up to date NSSN.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 16:55:50 +03:00
Emmanuel Grumbach
4bdd4dfe7a iwlwifi: advertise maximal MPDU length when Rx MQ is supported
The new hardware that supports multiple queue also
de-aggregates A-MSDUs. This means that we can advertise
the maximal size of A-MSDUs regardless of the receive
buffer's size.
In order to be able to forcefully use a lower A-MSDU size,
add a default value for the module parameter. Pre-9000
will have a default of 4K, and 9000 will have 12K.
Setting the amsdu_size module parameter to 4K will limit
the A-MSDU on 9000 as well.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-07-01 16:51:22 +03:00
Emmanuel Grumbach
5c8877593a iwlwifi: add default value to disable_11ac mod param description
Small change to make it clear that the default value is false.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:10 +03:00
Sara Sharon
dfcfeef96c iwlwifi: pcie: grab NIC access only once on RX init
When initializing RX we grab NIC access for every read and
write. This is redundant - we can just grab access once.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:10 +03:00
Sara Sharon
1554ed2088 iwlwifi: pcie: use shadow registers for updating write pointer
The RX queues have a shadow register for the write pointer
that enables updates without grabbing NIC access. Use them
instead of the periphery registers because accessing those
is much more expensive.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:09 +03:00
Liad Kaufman
cf961e1662 iwlwifi: mvm: support dqa-mode agg on non-shared queue
In non-shared queues, DQA requires re-configuring existing
queues to become aggregated rather than allocating a new
one. It also requires "un-aggregating" an existing queue
when aggregations are turned off.

Support this requirement for non-shared queues.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:09 +03:00
Johannes Berg
192185d68d iwlwifi: pcie: avoid msleep() with short timeout
Since msleep is based on jiffies, it can sleep for a long time.
Use usleep_range() instead to shorten the maximum time.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:08 +03:00
Johannes Berg
b7a08b284d iwlwifi: pcie: extend device reset delay
Newer hardware generations will take longer to be accessible again
after reset, so we need to wait longer before continuing any flow
that did a reset.

Rather than make the wait time configurable, simply extend it for
all.

Since all of these code paths can sleep, use usleep_range() rather
than mdelay().

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:07 +03:00
Gregory Greenman
fbbd48595f iwlwifi: turn on SGI support for VHT 160MHz
Devices supporting VHT 160MHz width are supporting also Short GI.
Turn on this capability in vht cap.

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:07 +03:00
Johannes Berg
77d7693134 iwlwifi: make configuration structs smaller
Since we have a lot of configuration structs (almost 70) saving
some memory in each one of them leads to an overall saving of
~2.6KiB of memory.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:06 +03:00
Emmanuel Grumbach
39654cb3a6 iwlwifi: don't access a nonexistent register upon assert
The commit below added code to dump the content of FIFOs
that are present only on dual CPU products (8000 and up).
This broke 7265D whose firmware does advertise
IWL_UCODE_TLV_CAPA_EXTEND_SHARED_MEM_CFG but doesn't have 2
CPUs. The current code does check the length of the FIFO
before dumping them (and the nonexistent FIFO has a 0
length), but we still accessed a register to set the FIFO
number and that made the DMA unhappy.

The impact was a much longer recovery upon firmware assert.

Fixes: 5b08641429 ("iwlwifi: mvm: support dumping UMAC internal txfifos")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:05 +03:00
Emmanuel Grumbach
75094dc848 iwlwifi: remove IWLWIFI_DEBUG_EXPERIMENTAL_UCODE
This Kconfig option allows to load a firmware for
debugging with a different name. This mechanism has not
been used for a few years now and replacing the firmware
file works as well.
Kill this Kconfig option and all the code that goes with it.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:05 +03:00
Sara Sharon
13303c0fb1 iwlwifi: mvm: use helpers to get iwl_mvm_sta
Getting the mvm station out of station id requires dereferencing
the station id to get ieee80211_sta, then checking for pointer
validity and only then extract mvm station out.
Given that there are helpers to do it - use them instead of
duplicating the code whenever we need only mvm station.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:04 +03:00
Sara Sharon
ce1f27787d iwlwifi: mvm: remove redundant alloc_ctx parameter
iwl_phy_db_set_section() is get called only from atomic
context, the alloc_ctx parameter is not needed. Remove it.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:03 +03:00
Sara Sharon
0ec84d1d1e iwlwifi: mvm: make phy_db size dynamic
Driver is agnostic to the number of the phy_db entries and
only serves the firmware as a pipe to move the data from init
image to RT image.
As the size of the arrays may change (as it does in 9000 device)
allocate it dynamically. Firmware sends the largest index first
so we can use this to know how much we should allocate.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:03 +03:00
Sara Sharon
dd02fbeb8f iwlwifi: mvm: set correct vht capability
Our device supports only 160 GHz and not 80+80. Fix
VHT flag accordingly.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:02 +03:00
Sara Sharon
74dd17648c iwlwifi: mvm: loosen nssn comparison to reorder buffer head
Up till now, the reorder buffer uses standard spec based comparison
when comparing the buffer status to NSSN. This indeed works for the
regular case, since we shouldn't cross the 2048 boundary without
getting a frame release notification.
However, this is problematic due to packet filtering that may be
performed by the FW while we are in d0i3. Theoretically we may
filter over 2048 packets, and then the check of the NSSN will get
incorrect.
Change the comparison to always trust nssn unless it is 64 or less
frames behind the head - which might happen due to a timeout.
This new comparison is to be used only when comparing reorder buffer
head with nssn, and not when comparing the packet SN to nssn or
reorder buffer head.
Put this in a separate commit as the logic is a bit tricky and
stands for its own commit message.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:01 +03:00
Haim Dreyfuss
7ef3dd264e iwlwifi: pcie: don't wake up the NIC when writing CSRs in MSIX mode
CSR registers are always available even when the NIC is not awake, no
need to wake up the NIC before accessing them. This has a huge impact
when we re-enable an interrupt at the end of the ISR since waking up the
NIC can take some time.

Signed-off-by: Haim Dreyfuss <haim.dreyfuss@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:34:01 +03:00
Haim Dreyfuss
0730ffb19e iwlwifi: Fix firmware name maximum length definition
Previous patch had changed firmware name convention for
new generation product. The firmware name is now longer
than the former convention. Adapt max firmware name length
to the new convention.

Fixes: e1ba684f76 ("iwlwifi: 8000: fix MODULE_FIRMWARE input")
Signed-off-by: Haim Dreyfuss <haim.dreyfuss@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:32:10 +03:00
Sara Sharon
16c45822a8 iwlwifi: mvm: don't allow negative reference count
Currently code allows mvm reference to become negative and
only warns in case mvm reference is released while reference
counting is 0.
However, we better prevent this from happening at all since
iwl_mvm_unref() may race against iwl_mvm_unref_all_except()
which is called on restart.
As a result we might get the same reference unreferenced twice
ending with a negative value:
An example for an easily reproduced log:
    [ 2689.909166] iwl_mvm_ref Take mvm reference - type 8
    [ 2690.732716] iwl_mvm_unref_all_except Cleanup: remove mvm ref type 8 (1)
    [ 2690.849708] iwl_mvm_unref Leave mvm reference - type 8
    [ 2690.849721] WARNING: ... iwl_mvm_unref+0xb0/0xc0 [iwlmvm]()

If there will be yet another another restart iwl_mvm_unref_all_except
will run from 0 up to ref count, and since it is unsigned, we will throw
the transport ref count completely out of balance:
    iwl_mvm_unref_all_except[I] -- Cleanup: remove mvm ref type 8 (255)
    iwl_trans_slv_unref[I] -- rpm counter: 0
    iwl_trans_slv_unref[I] -- rpm counter: -1
    iwl_trans_slv_unref[I] -- rpm counter: -2
 ...
    iwl_trans_slv_unref[I] -- rpm counter: -253
    iwl_trans_slv_unref[I] -- rpm counter: -254

As there is no valid scenario where we can get to a negative
reference count - prevent it from happening.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
2016-05-10 22:14:52 +03:00