Commit graph

335,609 commits

Author SHA1 Message Date
Stephen Warren
fef40b2369 Merge commit 'xceiv-for-v3.7' into for-3.7/cleanup2 2012-09-14 11:35:16 -06:00
Stephen Warren
f49540d1d7 Merge branch 'for-3.7/common-clk' into for-3.7/cleanup2 2012-09-14 11:34:53 -06:00
Stephen Warren
1f10478cab Merge branch 'for-3.7/board-removal' into for-3.7/cleanup2 2012-09-14 11:34:47 -06:00
Stephen Warren
be972c3272 ARM: dt: tegra: harmony: configure power off
Add DT property to tell the TPS6586x that it should provide the
pm_power_off() implementation. This allows "shutdown" to work.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
2012-09-14 11:31:37 -06:00
Laxman Dewangan
3cc404de24 ARM: dt: tegra: harmony: add regulators
Harmony uses a TPS6586x regulator. Instantiate this, and hook up a
couple of fixed GPIO-controlled regulators too.

Based on Ventana regulator patch by Stephen Warren <swarren@nvidia.com>
and converted to Harmony.

swarren made the following changes:
* Added ldo0 regulator configuration to device tree, and updated
  board-harmony-pcie.c for the new regulator name.
* Fixed vdd_1v05's voltage from 10.5V to 1.05V.
* Modified board-harmony-pcie.c to obtain the en_vdd_1v05 GPIO number at
  run-time from device tree instead of hard-coding it.
* Removed board-harmony{-power.c,.h} now that they're unused.
* Disabled vdd_1v05 regulator; the code in board-harmony-pcie.c hijacks
  this GPIO for now. This will be fixed when the PCIe driver is re-
  written as a driver. The code can't regulator_get("vdd_1v05") right
  now, because the vdd_1v05 regulator's probe gets deferred due to its
  supply being the PMIC, which gets probed after the regulator the first
  time around, and this dependency is only resolved by repeated probing,
  which happens when deferred_probe_initcall() is called, which happens
  in a late initcall, whose runtime order relative to harmony_pcie_init()
  is undefined, since that's also called from a late initcall.
* Removed unused harmony_pcie_initcall().

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
2012-09-14 11:31:37 -06:00
Stephen Warren
bb25af8167 ARM: tegra: remove board (but not DT) support for Harmony
Harmony can be booted using device tree with equal functionality as when
booted using a board file. Remove as much of the board file as is
possible, since it's no longer needed.

Two special-cases are still left in board-dt-tegra20.c, since the Tegra
PCIe driver doesn't support device tree yet, and the Harmony .dts file
doesn't yet describe regulators which are needed for PCIe. This logic is
now enabled unconditionally rather than via CONFIG_MACH_HARMONY. While
this is more code than other boards, it's still unlikely to be much of a
problem, and both regulators and PCIe should be supported via device tree
in the near future, allowing the remaining code to be removed.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
2012-09-14 11:31:36 -06:00
Stephen Warren
cff1dfbfcd ARM: tegra: remove board (but not DT) support for Paz00
Paz00 (Toshiba AC100) can be booted using device tree with equal
functionality as when booted using a board file. Remove as much of the
board file as is possible, since it's no longer needed.

One special-case is still left in board-dt-tegra20.c, since there is no
way to create a WiFi rfkill device from device tree yet. This logic is
now enabled unconditionally rather than via CONFIG_MACH_PAZ00. The extra
cases where it's enabled (.configs which did not enable Paz00 support)
shouldn't impact much since the amount of code is tiny.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-By: Marc Dietrich <marvin24@gmx.de>
2012-09-14 11:31:36 -06:00
Stephen Warren
be6a9194f1 ARM: tegra: remove board (but not DT) support for TrimSlice
TrimSlice can be booted using device tree with equal functionality as
when booted using a board file. Remove the board file since it's no
longer needed.

One special-case is still left in board-dt-tegra20.c, since the Tegra
PCIe driver doesn't support device tree yet. This logic is now enabled
by CONFIG_TEGRA_PCI rather than via CONFIG_MACH_TRIMSLICE. The extra
cases where it's enabled (.configs which did not enable TrimSlice
support) shouldn't impact much since the amount of code is tiny.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
2012-09-14 11:31:36 -06:00
Stephen Warren
1ab710fe61 Merge commit 'tps6589x-dt' into for-3.7/board-removal 2012-09-14 11:30:56 -06:00
Saurav Kashyap
09543c09ea [SCSI] qla2xxx: Display mailbox failure by default.
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 18:28:46 +01:00
Masanari Iida
d6a03581a3 [SCSI] qla2xxx: Fix typo in qla2xxx files
Correct spelling typo within qla2xxx files.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 18:28:46 +01:00
Chad Dupuis
7916bb90e2 [SCSI] qla2xxx: Add check in qla82xx_watchdog for failed hardware state.
Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 18:28:45 +01:00
Joe Carnuccio
9ebb5d9c69 [SCSI] qla2xxx: Add I2C BSG interface.
Add BSG interface to generically access I2C attached devices.

Signed-off-by: Joe Carnuccio <joe.carnuccio@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 18:28:45 +01:00
Chad Dupuis
650f528f35 [SCSI] qla2xxx: Bind to ISP8031 devices.
Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 18:28:45 +01:00
Ben Hutchings
4b961180ef [media] rc: ite-cir: Initialise ite_dev::rdev earlier
ite_dev::rdev is currently initialised in ite_probe() after
rc_register_device() returns.  If a newly registered device is opened
quickly enough, we may enable interrupts and try to use ite_dev::rdev
before it has been initialised.  Move it up to the earliest point we
can, right after calling rc_allocate_device().

Reported-and-tested-by: YunQiang Su <wzssyqa@gmail.com>

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-09-14 14:04:16 -03:00
Bo Shen
985b11fa80 ASoC: wm8904: correct the index
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2012-09-14 18:02:38 +01:00
Hanjun Guo
20953a6277 [SCSI] Fusion MPT: disable pci device when mpt map resoures failed
when probe a pci device, first we enable it, and disable it when
some error happened in the following process, because the power
state of the device is set to D0, and if MSI is disabled,
we will allocate irq and register gsi for this device in the enable process.

In function mpt_mapresources(MPT_ADAPTER *ioc), it forgot disable the
pci device when error happened, the irq and gsi will never be released.
this patch will fix it.

Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: "Nandigama, Nagalakshmi" <Nagalakshmi.Nandigama@lsi.com> 
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:29 +01:00
Jeff Mahoney
6ed33a4a0b [SCSI] st: raise device limit
The device limit of 128 tape drives was established in 2003 as a
significant increase from the 8 tape drives allowed previously.

We're seeing customer sites that between a large number of drives
and multipath are discovering more than 128 devices and running
into problems.

Now that we're not stuck having to store a pointer in array
and aren't limited by kmalloc failing on higher order allocs we can
lift the limit to fill the entire minor range based on the number
of modes.

Based on the current code, that's 2^17 devices.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:29 +01:00
Jeff Mahoney
26898afd67 [SCSI] st: clean up device file creation and removal
This patch cleans up the st device file creation and removal.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:29 +01:00
Jeff Mahoney
6c648d95a6 [SCSI] st: get rid of scsi_tapes array
st currently allocates an array to store pointers to all of the
scsi_tape objects. It's used to discover available indexes to use as the
base for the minor number selection and later to look up scsi_tape
devices for character devices.

We switch to using an IDR for minor selection and a pointer from
st_modedef back to scsi_tape for the lookups.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:28 +01:00
Jeff Mahoney
e3f2a9cc84 [SCSI] st: clean up dev cleanup in st_probe
st_probe leaves a cdev pointer hanging around that is compared
during the error path and freed later. There's no need for the pointer
to hang around at all. So we free it immediately and simplify the error
handling.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:28 +01:00
Jeff Mahoney
af23782bef [SCSI] st: Use static class attributes
st currently sets up and tears down class attributes manually for
every tape drive in the system. This patch uses a statically defined
class with class attributes to let the device core do it for us.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:28 +01:00
John Soni Jose
06047689a9 [SCSI] be2iscsi: Bump the driver version.
Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:28 +01:00
John Soni Jose
0a513dd873 [SCSI] be2iscsi: Fix a kernel panic because of TCP RST/FIN received.
A TCP RST/FIN can be received even before the connection specific
structures are initialized.This fix checks for the conn structure
is intialized or not  when RST/FIN is received.

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:27 +01:00
John Soni Jose
6f72238e77 [SCSI] be2iscsi: Add support for configuring the VLAN on the adapter.
Add support for configuring the VLAN parameters on the adapter
using the iscsiadm interface.

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:27 +01:00
John Soni Jose
df5d0e6ee9 [SCSI] be2iscsi: Format the MAC_ADDR with sysfs_format_mac.
The MAC_ADDR stored in driver private structure is of
unsigned char data type but strlcpy parameters is of
signed char data type. This conversion of data types
lead to change in the value.This changed value is passed
to the upper layer and junk characters were displayed
when "iscsiadm -m iface" command was run.

In case of iSCSI boot, since the the MAC_ADDR was coming
junk the boot was also not working

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:27 +01:00
John Soni Jose
99bc5d55c0 [SCSI] be2iscsi: Added Logging mechanism for the driver.
Added new log level mechanism for different events. These
log levels can be set at driver load time/run time. The
log level is set for each Scsi_host.

Fixed few multi-line print warning to get over the new checkpatch.pl
warnings on multi-line strings.

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:27 +01:00
John Soni Jose
9aef4200ee [SCSI] be2iscsi: Issue MBX Cmd for login to boot target in crashdump mode
When the driver comes up in crashdump mode, it has to explicitly
issue command to FW for logging to the boot target. This fix issues
MBX Cmd to login to boot target in crashdump mode.

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:26 +01:00
John Soni Jose
afd96fa45b [SCSI] be2iscsi: Removing the iscsi_data_pdu setting.
The setting of iscsi_data_pdu is not required anymore,
as this was required for BE1 adapters only. The BE1 adapter
were not supported in any previous versions of the kernel.

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:26 +01:00
James Smart
c66c013ffa [SCSI] lpfc 8.3.34: Update lpfc version for 8.3.34 driver release
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:26 +01:00
James Smart
cdcc2343fe [SCSI] lpfc 8.3.34: Fixed leaking memory from pci dma pool
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:25 +01:00
James Smart
92e3af663a [SCSI] lpfc 8.3.34: Correct lock handling to eliminate reset escalation on I/O abort
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:25 +01:00
James Smart
1c13bf6648 [SCSI] lpfc 8.3.34: Adjust IO Channels to 1 when INTx
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:24 +01:00
James Smart
247ca945d8 [SCSI] lpfc 8.3.34: Add XRI to abort handler timeout log message
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:24 +01:00
James Smart
aa1c7ee74a [SCSI] lpfc 8.3.34: Streamline fcp underrun message printing
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:24 +01:00
James Smart
a51a17831b [SCSI] lpfc 8.3.34: Correct typecasts for snprintf messages
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:24 +01:00
James Smart
2613470a5f [SCSI] lpfc 8.3.34: Simplify BlockGuard lpfc_printf_vlog messages
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:23 +01:00
James Smart
e3d2b802ad [SCSI] lpfc 8.3.34: Fix parameter field in CQE to mask for LOCAL_REJECT status
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:23 +01:00
James Smart
90695ee0e9 [SCSI] lpfc 8.3.34: Fix number of IO channels to match CPUs
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:23 +01:00
James Smart
8aa134a836 [SCSI] lpfc 8.3.34: Add SLI-4 V1 Capacity and Resource Descriptor support
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:22 +01:00
James Smart
086a345f9d [SCSI] lpfc 8.3.34: Add LOGO support after ABTS compliance
Make compliant with FC specs by sending LOGO after ABTS timeouts

Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:22 +01:00
Vikas Chaudhary
0e58076b37 [SCSI] scsi_lib: Set the device state from transport-offline to running
FC and iSCSI class set SCSI devices to transport-offline state after
fast_io_fail/replacement_timeout has fired, but after relogin, function
scsi_internal_device_unblock() is not setting scsi device state to running.
Due to this the devices even after being relogged in remain offline.

Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:22 +01:00
Vikas Chaudhary
d53efb9d51 [SCSI] qla4xxx: Update driver version to 5.02.00-k19
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:22 +01:00
Lalit Chandivade
24c1420094 [SCSI] qla4xxx: Properly handle SCSI underrun while processing status IOCBs.
The current code would incorrectly return a DID_OK for a
CHECK CONDITION with Recovered error sense key causing incorrect
completion of a command when there is a dropped frame.

Signed-off-by: Lalit Chandivade <lalit.chandivade@qlogic.com>
Signed-off-by: Tej Parkash <tej.parkash@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:21 +01:00
Manish Rangankar
80c53e649d [SCSI] qla4xxx: Fix multiple conn login event issue during session recovery.
During iscsid session recovery driver sends multiple ISCSI_CONN_STATE_LOGGED_IN
event from qla4xxx_conn_start() and qla4xxx_ddb_change(), which causes iscsid
to crash.

Signed-off-by: Manish Rangankar <manish.rangankar@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:21 +01:00
Vikas Chaudhary
26fdf92297 [SCSI] qla4xxx: Fix gcc warning for x86 system
Fix warning:-
drivers/scsi/qla4xxx/ql4_nx.c:1867:2: warning: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 5 has type ‘uint32_t’ [-Wformat]

Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:20 +01:00
Manish Rangankar
d46bdeb144 [SCSI] qla4xxx: Fix memory corruption issue in qla4xxx_ep_connect.
In qla4xxx_ep_connect(), qla_ep->dst_addr and dst_addr are type
struct sockaddr. We are copying sizeof(struct sockaddr_in6) bytes
from dst_addr to qla_ep->dst_addr which is 12 bytes larger. This
will cause memory corruption. So we change qla_ep->dst_addr to
struct sockaddr_storage which is of 128 byte, large enough to
hold sizeof(struct sockaddr_in6).

Signed-off-by: Manish Rangankar <manish.rangankar@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-09-14 17:59:19 +01:00
Daniel Wagner
a6f00298b2 cgroup: Define CGROUP_SUBSYS_COUNT according the configuration
Since we know exactly how many subsystems exists at compile time we are
able to define CGROUP_SUBSYS_COUNT correctly. CGROUP_SUBSYS_COUNT will
be at max 12 (all controllers enabled). Depending on the architecture
we safe either 32 - 12 pointers (80 bytes) or 64 - 12 pointers (416
bytes) per cgroup.

With this change we can also remove the temporary placeholder to avoid
compilation errors.

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
2012-09-14 09:57:47 -07:00
Daniel Wagner
8a8e04df47 cgroup: Assign subsystem IDs during compile time
WARNING: With this change it is impossible to load external built
controllers anymore.

In case where CONFIG_NETPRIO_CGROUP=m and CONFIG_NET_CLS_CGROUP=m is
set, corresponding subsys_id should also be a constant. Up to now,
net_prio_subsys_id and net_cls_subsys_id would be of the type int and
the value would be assigned during runtime.

By switching the macro definition IS_SUBSYS_ENABLED from IS_BUILTIN
to IS_ENABLED, all *_subsys_id will have constant value. That means we
need to remove all the code which assumes a value can be assigned to
net_prio_subsys_id and net_cls_subsys_id.

A close look is necessary on the RCU part which was introduces by
following patch:

  commit f845172531
  Author:	Herbert Xu <herbert@gondor.apana.org.au>  Mon May 24 09:12:34 2010
  Committer:	David S. Miller <davem@davemloft.net>  Mon May 24 09:12:34 2010

  cls_cgroup: Store classid in struct sock

  Tis code was added to init_cgroup_cls()

	  /* We can't use rcu_assign_pointer because this is an int. */
	  smp_wmb();
	  net_cls_subsys_id = net_cls_subsys.subsys_id;

  respectively to exit_cgroup_cls()

	  net_cls_subsys_id = -1;
	  synchronize_rcu();

  and in module version of task_cls_classid()

	  rcu_read_lock();
	  id = rcu_dereference(net_cls_subsys_id);
	  if (id >= 0)
		  classid = container_of(task_subsys_state(p, id),
					 struct cgroup_cls_state, css)->classid;
	  rcu_read_unlock();

Without an explicit explaination why the RCU part is needed. (The
rcu_deference was fixed by exchanging it to rcu_derefence_index_check()
in a later commit, but that is a minor detail.)

So here is my pondering why it was introduced and why it safe to
remove it now. Note that this code was copied over to net_prio the
reasoning holds for that subsystem too.

The idea behind the RCU use for net_cls_subsys_id is to make sure we
get a valid pointer back from task_subsys_state(). task_subsys_state()
is just blindly accessing the subsys array and returning the
pointer. Obviously, passing in -1 as id into task_subsys_state()
returns an invalid value (out of lower bound).

So this code makes sure that only after module is loaded and the
subsystem registered, the id is assigned.

Before unregistering the module all old readers must have left the
critical section. This is done by assigning -1 to the id and issuing a
synchronized_rcu(). Any new readers wont call task_subsys_state()
anymore and therefore it is safe to unregister the subsystem.

The new code relies on the same trick, but it looks at the subsys
pointer return by task_subsys_state() (remember the id is constant
and therefore we allways have a valid index into the subsys
array).

No precautions need to be taken during module loading
module. Eventually, all CPUs will get a valid pointer back from
task_subsys_state() because rebind_subsystem() which is called after
the module init() function will assigned subsys[net_cls_subsys_id] the
newly loaded module subsystem pointer.

When the subsystem is about to be removed, rebind_subsystem() will
called before the module exit() function. In this case,
rebind_subsys() will assign subsys[net_cls_subsys_id] a NULL pointer
and then it calls synchronize_rcu(). All old readers have left by then
the critical section. Any new reader wont access the subsystem
anymore.  At this point we are safe to unregister the subsystem. No
synchronize_rcu() call is needed.

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
2012-09-14 09:57:43 -07:00
Daniel Wagner
80f4c87774 cgroup: Do not depend on a given order when populating the subsys array
The *_subsys_id will be used as index to access the subsys. Therefore
we need to care we populate the subsystem at the correct position by
using designated initialization.

With this change we are able to interleave builtin and modules in the subsys
array.

Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
2012-09-14 09:57:40 -07:00