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506,942 commits

Author SHA1 Message Date
Clemens Ladisch
49f4b4d15c ALSA: usb-audio: add MIDI port names for the Yamaha MOTIF XF
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-09-08 10:54:39 +02:00
Clemens Ladisch
df1e471966 ALSA: pcm: snd_interval_step: fix changes of open intervals
Changing an interval boundary to a multiple of the step size makes that
boundary exact.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-09-08 10:54:25 +02:00
Clemens Ladisch
0f519b6221 ALSA: pcm: snd_interval_step: drop the min parameter
The min parameter was not used by any caller.  And if it were used,
underflows in the calculations could lead to incorrect results.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2014-09-08 10:54:18 +02:00
Gaël PORTAY
d07a1ecdfb clocksource: tcb_clksrc: sanitize IRQ request
The clock is not unprepared in case of the request IRQ fails.

Also update to request_irq.

Signed-off-by: Gaël PORTAY <gael.portay@gmail.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2014-09-08 10:54:03 +02:00
Gaël PORTAY
84f462371c ARM: at91/tclib: mask interruptions at shutdown and probe
Shutdown properly the timer counter block by masking interruptions. Otherwise,
a segmentation may happen when kexec-ing a new kernel (see backtrace below).
An interruption may happen before the handler is set, leading to a kernel
segmentation fault.

Furthermore, we make sure the interruptions are masked when the driver is
initialized. This will prevent freshly kexec-ed kernel from crashing when
launched from a kernel which does not properly mask interruptions at shutdown.

The backtrace below happened after kexec-ing a new kernel, from a kernel
that did not shut down properly leaving interruptions unmasked.

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 80000005 [#1] ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0+ #144
task: c1828aa0 ti: c182a000 task.ti: c182a000
PC is at 0x0
LR is at ch2_irq+0x28/0x30
pc : [<00000000>]    lr : [<c01db904>]    psr: 000000d3
sp : c182bd38  ip : c182bd48  fp : c182bd44
r10: c0373390  r9 : c1825b00  r8 : 60000053
r7 : 00000000  r6 : 00000000  r5 : 00000013  r4 : c036e800
r3 : 00000000  r2 : 00002004  r1 : c036e760  r0 : c036e760
Flags: nzcv  IRQs off  FIQs off  Mode SVC_32  ISA ARM  Segment kernel
Control: 0005317f  Table: 20004000  DAC: 00000017
Process swapper (pid: 1, stack limit = 0xc182a1c0)
Stack: (0xc182bd38 to 0xc182c000)
bd20:                                                       c182bd7c c182bd48
bd40: c0045430 c01db8ec 00000000 c18c6f40 c182bd74 c1825b00 c035cec4 00000000
bd60: c182be2c 60000053 c1825b34 00000000 c182bd94 c182bd80 c0045570 c0045408
bd80: 00000000 c1825b00 c182bdac c182bd98 c0047f34 c0045550 00000013 c036619c
bda0: c182bdc4 c182bdb0 c0044da4 c0047e98 0000007f 00000013 c182bde4 c182bdc8
bdc0: c0009e34 c0044d8c fefff000 c0046728 60000053 ffffffff c182bdf4 c182bde8
bde0: c00086a8 c0009ddc c182be74 c182bdf8 c000cb80 c0008674 00000000 00000013
be00: 00000000 00014200 c1825b00 c036e800 00000013 c035ed98 60000053 c1825b34
be20: 00000000 c182be74 c182be20 c182be40 c0047994 c0046728 60000053 ffffffff
be40: 00000013 c036e800 c182be64 c1825b00 00000013 c036e800 c035ed98 c03874bc
be60: 00000004 c036e700 c182be94 c182be78 c004689c c0046398 c036e760 c18c6080
be80: 00000000 c035ed10 c182bedc c182be98 c0348b08 c004684c 0000000c c034dac8
bea0: 004c4b3f c028c338 c036e760 00000013 c014ecc8 c18e67e0 c035b9c0 c0348884
bec0: c035b9c0 c182a020 00000000 00000000 c182bf54 c182bee0 c00089fc c0348894
bee0: c00da51c c1ffcc78 c182bf0c c182bef8 c002d100 c002d09c c1ffcc78 00000000
bf00: c182bf54 c182bf10 c002d308 c0336570 c182bf3c c0334e44 00000003 00000003
bf20: 00000030 c0334b44 c0044d74 00000003 00000003 c034dac8 c0350a94 c0373440
bf40: c0373440 00000030 c182bf94 c182bf58 c0336d24 c000890c 00000003 00000003
bf60: c0336560 c182bf64 c182bf64 6e616e0d 00000000 c0272fc8 00000000 00000000
bf80: 00000000 00000000 c182bfac c182bf98 c0272fd8 c0336bd8 c182a000 00000000
bfa0: 00000000 c182bfb0 c00095d0 c0272fd8 00000000 00000000 00000000 00000000
bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 374d27cd 33cc33e4
Backtrace:
[<c01db8dc>] (ch2_irq) from [<c0045430>] (handle_irq_event_percpu+0x38/0x148)
[<c00453f8>] (handle_irq_event_percpu) from [<c0045570>] (handle_irq_event+0x30/0x40)
 r10:00000000 r9:c1825b34 r8:60000053 r7:c182be2c r6:00000000 r5:c035cec4
 r4:c1825b00
[<c0045540>] (handle_irq_event) from [<c0047f34>] (handle_fasteoi_irq+0xac/0x11c)
 r4:c1825b00 r3:00000000
[<c0047e88>] (handle_fasteoi_irq) from [<c0044da4>] (generic_handle_irq+0x28/0x38)
 r5:c036619c r4:00000013
[<c0044d7c>] (generic_handle_irq) from [<c0009e34>] (handle_IRQ+0x68/0x88)
 r4:00000013 r3:0000007f
[<c0009dcc>] (handle_IRQ) from [<c00086a8>] (at91_aic_handle_irq+0x44/0x4c)
 r6:ffffffff r5:60000053 r4:c0046728 r3:fefff000
[<c0008664>] (at91_aic_handle_irq) from [<c000cb80>] (__irq_svc+0x40/0x4c)
Exception stack(0xc182bdf8 to 0xc182be40)
bde0:                                                       00000000 00000013
be00: 00000000 00014200 c1825b00 c036e800 00000013 c035ed98 60000053 c1825b34
be20: 00000000 c182be74 c182be20 c182be40 c0047994 c0046728 60000053 ffffffff
[<c0046388>] (__setup_irq) from [<c004689c>] (setup_irq+0x60/0x8c)
 r10:c036e700 r9:00000004 r8:c03874bc r7:c035ed98 r6:c036e800 r5:00000013
 r4:c1825b00
[<c004683c>] (setup_irq) from [<c0348b08>] (tcb_clksrc_init+0x284/0x31c)
 r6:c035ed10 r5:00000000 r4:c18c6080 r3:c036e760
[<c0348884>] (tcb_clksrc_init) from [<c00089fc>] (do_one_initcall+0x100/0x1b4)
 r10:00000000 r9:00000000 r8:c182a020 r7:c035b9c0 r6:c0348884 r5:c035b9c0
 r4:c18e67e0
[<c00088fc>] (do_one_initcall) from [<c0336d24>] (kernel_init_freeable+0x15c/0x224)
 r9:00000030 r8:c0373440 r7:c0373440 r6:c0350a94 r5:c034dac8 r4:00000003
[<c0336bc8>] (kernel_init_freeable) from [<c0272fd8>] (kernel_init+0x10/0xec)
 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c0272fc8 r4:00000000
[<c0272fc8>] (kernel_init) from [<c00095d0>] (ret_from_fork+0x14/0x24)
 r4:00000000 r3:c182a000
Code: bad PC value
---[ end trace 5b30f0017e282e47 ]---
Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: Gaël PORTAY <gael.portay@gmail.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2014-09-08 10:54:03 +02:00
Gaël PORTAY
4930d247af ARM: at91/tclib: move initialization from alloc to probe
Move resource retrieval from atmel_tc_alloc to tc_probe to avoid lately
reporting resource related issues when a TC block user request a TC block.

Moreover, resources retrieval are usually done in the probe function,
thus moving them add some consistency with other drivers.

Initialization is done once, ie not every time a tc block is requested.
If it fails, the device is not appended to the list of tc blocks.

Furhermore, the device id is retrieved at probe as well, avoiding parsing
DT every time the user requests of tc block.

Signed-off-by: Gaël PORTAY <gael.portay@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2014-09-08 10:54:03 +02:00
Gaël PORTAY
8495497f92 ARM: at91/tclib: prefer using of devm_* functions
Signed-off-by: Gaël PORTAY <gael.portay@gmail.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2014-09-08 10:54:03 +02:00
Steinar H. Gunderson
c8d6591752 mac80211: support DTPC IE (from Cisco Client eXtensions)
Linux already supports 802.11h, where the access point can tell the
client to reduce its transmission power. However, 802.11h is only
defined for 5 GHz, where the need for this is much smaller than on
2.4 GHz.

Cisco has their own solution, called DTPC (Dynamic Transmit Power
Control). Cisco APs on a controller sometimes but not always send
802.11h; they always send DTPC, even on 2.4 GHz. This patch adds support
for parsing and honoring the DTPC IE in addition to the 802.11h
element (they do not always contain the same limits, so both must
be honored); the format is not documented, but very simple.

Tested (on top of wireless.git and on 3.16.1) against a Cisco Aironet
1142 joined to a Cisco 2504 WLC, by setting various transmit power
levels for the given access points and observing the results.
The Wireshark 802.11 dissector agrees with the interpretation of the
element, except for negative numbers, which seem to never happen
anyway.

Signed-off-by: Steinar H. Gunderson <sgunderson@bigfoot.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
2014-09-08 10:52:00 +02:00
Steinar H. Gunderson
24a4e4008c mac80211: split 802.11h parsing from transmit power policy
Decouple the logic of parsing the 802.11d and 802.11h IEs from the
part of deciding what to do about the data (messaging, clamping to
0 dBm, doing the actual setting). This paves the way for the next
patch, which introduces more data sources for transmit power limitation.

Signed-off-by: Steinar H. Gunderson <sgunderson@bigfoot.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2014-09-08 10:43:18 +02:00
Bartlomiej Zolnierkiewicz
221414db19 mmc: sdhci-s3c: fix runtime PM handling on sdhci_add_host() failure
Runtime Power Management handling for the sdhci_add_host() failure
case in sdhci_s3c_probe() should match the code in sdhci_s3c_remove()
(which uses pm_runtime_disable() call which matches the earlier
pm_runtime_enable() one).  Fix it.

This patch fixes "BUG: spinlock bad magic on CPU#0, swapper/0/1" and
"Unbalanced pm_runtime_enable!" warnings.

>From the kernel log:
...
[    1.659631] s3c-sdhci 12530000.sdhci: sdhci_add_host() failed
[    1.665096] BUG: spinlock bad magic on CPU#0, swapper/0/1
[    1.670433]  lock: 0xea01e484, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[    1.677895] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.16.0-next-20140804-00008-ga59480f-dirty #707
[    1.687037] [<c0013ae4>] (unwind_backtrace) from [<c0010d70>] (show_stack+0x10/0x14)
[    1.694740] [<c0010d70>] (show_stack) from [<c04050c8>] (dump_stack+0x68/0xb8)
[    1.701948] [<c04050c8>] (dump_stack) from [<c0052558>] (do_raw_spin_lock+0x15c/0x1a4)
[    1.709848] [<c0052558>] (do_raw_spin_lock) from [<c040a630>] (_raw_spin_lock_irqsave+0x20/0x28)
[    1.718619] [<c040a630>] (_raw_spin_lock_irqsave) from [<c030d7d0>] (sdhci_do_set_ios+0x1c/0x5cc)
[    1.727464] [<c030d7d0>] (sdhci_do_set_ios) from [<c030ddfc>] (sdhci_runtime_resume_host+0x50/0x104)
[    1.736574] [<c030ddfc>] (sdhci_runtime_resume_host) from [<c02462dc>] (pm_generic_runtime_resume+0x2c/0x40)
[    1.746383] [<c02462dc>] (pm_generic_runtime_resume) from [<c0247898>] (__rpm_callback+0x34/0x70)
[    1.755233] [<c0247898>] (__rpm_callback) from [<c02478fc>] (rpm_callback+0x28/0x88)
[    1.762958] [<c02478fc>] (rpm_callback) from [<c02486f0>] (rpm_resume+0x384/0x4ec)
[    1.770511] [<c02486f0>] (rpm_resume) from [<c02488b0>] (pm_runtime_forbid+0x58/0x64)
[    1.778325] [<c02488b0>] (pm_runtime_forbid) from [<c030ea70>] (sdhci_s3c_probe+0x4a4/0x540)
[    1.786749] [<c030ea70>] (sdhci_s3c_probe) from [<c02429cc>] (platform_drv_probe+0x2c/0x5c)
[    1.795076] [<c02429cc>] (platform_drv_probe) from [<c02415f0>] (driver_probe_device+0x114/0x234)
[    1.803929] [<c02415f0>] (driver_probe_device) from [<c024179c>] (__driver_attach+0x8c/0x90)
[    1.812347] [<c024179c>] (__driver_attach) from [<c023ffb4>] (bus_for_each_dev+0x54/0x88)
[    1.820506] [<c023ffb4>] (bus_for_each_dev) from [<c0240df8>] (bus_add_driver+0xd8/0x1cc)
[    1.828665] [<c0240df8>] (bus_add_driver) from [<c0241db8>] (driver_register+0x78/0xf4)
[    1.836652] [<c0241db8>] (driver_register) from [<c00088a4>] (do_one_initcall+0x80/0x1d0)
[    1.844816] [<c00088a4>] (do_one_initcall) from [<c059ac94>] (kernel_init_freeable+0x108/0x1d4)
[    1.853503] [<c059ac94>] (kernel_init_freeable) from [<c0401300>] (kernel_init+0x8/0xe4)
[    1.861568] [<c0401300>] (kernel_init) from [<c000e538>] (ret_from_fork+0x14/0x3c)
[    1.869582] platform 12530000.sdhci: Driver s3c-sdhci requests probe deferral
...
[    1.997047] s3c-sdhci 12530000.sdhci: Unbalanced pm_runtime_enable!
...
[    2.027235] s3c-sdhci 12530000.sdhci: sdhci_add_host() failed
[    2.032884] platform 12530000.sdhci: Driver s3c-sdhci requests probe deferral
...

Tested on Hardkernel's Exynos4412 based ODROID-U3 board.

Fixes: 9f4e8151db ("mmc: sdhci-s3c: Enable runtime power management")
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2014-09-08 10:23:04 +02:00
Richard Weinberger
2570741ac8 score: Remove GENERIC_HAS_IOMAP
The symbol is an orphan, get rid of it.

Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Lennox Wu <lennox.wu@gmail.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
[Guenter Roeck: Merge with 3.17-rc3; update headline]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-08 10:15:36 +02:00
John DeSilva
5df4eb054f HID: Add Holtek USB ID 04d9:a0c2 ETEKCITY Scroll
The report descriptor for the HOLTEK USB ID 04d9:a0c2 (ETEKCITY Scroll
T-140 Gaming Mouse) is set to a very large amount of consumer usages
(2^16), exceeding HID_MAX_USAGES. Added id, bindings and comments for
the mouse, added to hid_have_special_driver, and reduced the usage and
logical maximums to 0x2fff, consistent with the other mice in the
category. Tested on the hardware.

Signed-off-by: John C. DeSilva <desilvjo@umich.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-08 09:48:56 +02:00
Hans Petter Selasky
643727a92e HID: fix ignore_special_drivers modparam description
Signed-off-by: Hans Petter Selasky <hps@selasky.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-08 09:35:35 +02:00
Johan Hovold
bfe3c873e9 HID: usbhid: enable always-poll quirk for Elan Touchscreen
Enable the always-poll quirk for Elan Touchscreens found on some recent
Samsung laptops.

Without this quirk the device keeps disconnecting from the bus (and is
re-enumerated) unless opened (and kept open, should an input event
occur).

Note that while the device can be run-time suspended, the autosuspend
timeout must be high enough to allow the device to be polled at least
once before being suspended. Specifically, using autosuspend_delay_ms=0
will still cause the device to disconnect on input events.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-08 09:29:16 +02:00
Johan Hovold
0b750b3baa HID: usbhid: add always-poll quirk
Add quirk to make sure that a device is always polled for input events
even if it hasn't been opened.

This is needed for devices that disconnects from the bus unless the
interrupt endpoint has been polled at least once or when not responding
to an input event (e.g. after having shut down X).

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-09-08 09:29:15 +02:00
Emmanuel Grumbach
f8dfc607b2 iwlwifi: dvm: disable power save by default
In
https://bugzilla.kernel.org/show_bug.cgi?id=84031,
the submitter said that disabling power saving helped,
do just that.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:18:47 +03:00
Johannes Berg
582de30afa iwlwifi: mvm: BT Coex - always initialize smps_mode
smps_mode is used uninitialized in a debug statement in AP
mode, so always initialize it.

While at it, fix a typo.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:18:36 +03:00
Emmanuel Grumbach
717e2390dc iwlwiwi: mvm: use bss_conf->dtim_period instead of conf.ps_dtim_period
The latter is meant for software implementation of power
save and is not per-virtual interface. Since our driver
supports multiple virtual interfaces, we need to use
vif->bss_conf.dtim_period.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:17:49 +03:00
Eyal Shapira
aa11bbf3df iwlwifi: mvm: treat EAPOLs like mgmt frames wrt rate
Using the LQ table which is initially set according to
the rssi could lead to EAPOLs being sent in high legacy
rates like 54mbps.
It's better to avoid sending EAPOLs in high rates as it reduces
the chances of a successful 4-Way handshake.
Avoid this and treat them like other mgmt frames which would
initially get sent at the basic rate.

Cc: <stable@vger.kernel.org> [3.13+]
Signed-off-by: Eyal Shapira <eyalx.shapira@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:17:29 +03:00
Johannes Berg
1bc10d3b50 iwlwifi: mvm: correctly handle PM/QoS changes from mac80211
When mac80211 requests multiple BSS config changes, as for example
while associating, we ignore power management and QoS changes and
only apply them later. Fix that by removing the "else" and making
the conditions independent.

Also move it after (potential) beacon filter enablement to have
that already enabled when going into power management code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:17:28 +03:00
Eliad Peller
22d059a5c7 iwlwifi: increase DEFAULT_MAX_TX_POWER
The chip is able to transmit up to 22dBm, so set
the constant appropriately.

CC: <stable@vger.kernel.org> [3.13+]
Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:17:19 +03:00
Emmanuel Grumbach
86974bff06 iwlwifi: mvm: fix endianity issues with Smart Fifo commands
This code was broken on big endian systems. Sparse didn't
catch the bug since the firmware command was not tagged as
little endian.
Fix the bug for big endian systems and tag the field in the
firmware command to prevent such issues in the future.

Cc: stable@vger.kernel.org [3.14+]
Fixes: 1f3b0ff8ec ("iwlwifi: mvm: Add Smart FIFO support")
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:17:09 +03:00
Luciano Coelho
7c8b3bc688 iwlwifi: mvm: set MAC_FILTER_IN_BEACON correctly for STA/P2P client
In commit cad3f08c (iwlwifi: mvm: enable MAC_FILTER_IN_BEACON when
forced_assoc_off is set) the code to set the MAC_FILTER_IN_BEACON flag
was accidentally moved to the main block of the if statement, while it
should be in the else block instead.  Move it to the right place.

Fixes: cad3f08c23 ("iwlwifi: mvm: enable MAC_FILTER_IN_BEACON when forced_assoc_off is set")
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:17:08 +03:00
Rik van Riel
eb1b4af0a6 sched, time: Atomically increment stime & utime
The functions task_cputime_adjusted and thread_group_cputime_adjusted()
can be called locklessly, as well as concurrently on many different CPUs.

This can occasionally lead to the utime and stime reported by times(), and
other syscalls like it, going backward. The cause for this appears to be
multiple threads racing in cputime_adjust(), both with values for utime or
stime that is larger than the original, but each with a different value.

Sometimes the larger value gets saved first, only to be immediately
overwritten with a smaller value by another thread.

Using atomic exchange prevents that problem, and ensures time
progresses monotonically.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: akpm@linux-foundation.org
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1408133138-22048-4-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-08 08:17:02 +02:00
Rik van Riel
e78c349679 time, signal: Protect resource use statistics with seqlock
Both times() and clock_gettime(CLOCK_PROCESS_CPUTIME_ID) have scalability
issues on large systems, due to both functions being serialized with a
lock.

The lock protects against reporting a wrong value, due to a thread in the
task group exiting, its statistics reporting up to the signal struct, and
that exited task's statistics being counted twice (or not at all).

Protecting that with a lock results in times() and clock_gettime() being
completely serialized on large systems.

This can be fixed by using a seqlock around the events that gather and
propagate statistics. As an additional benefit, the protection code can
be moved into thread_group_cputime(), slightly simplifying the calling
functions.

In the case of posix_cpu_clock_get_task() things can be simplified a
lot, because the calling function already ensures that the task sticks
around, and the rest is now taken care of in thread_group_cputime().

This way the statistics reporting code can run lockless.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Daeseok Youn <daeseok.youn@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guillaume Morin <guillaume@morinfr.org>
Cc: Ionut Alexa <ionut.m.alexa@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Link: http://lkml.kernel.org/r/20140816134010.26a9b572@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-08 08:17:01 +02:00
Rik van Riel
90ed9cbe76 exit: Always reap resource stats in __exit_signal()
Oleg pointed out that wait_task_zombie adds a task's usage statistics
to the parent's signal struct, but the task's own signal struct should
also propagate the statistics at exit time.

This allows thread_group_cputime(reaped_zombie) to get the statistics
after __unhash_process() has made the task invisible to for_each_thread,
but before the thread has actually been rcu freed, making sure no
non-monotonic results are returned inside that window.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Guillaume Morin <guillaume@morinfr.org>
Cc: Ionut Alexa <ionut.m.alexa@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Link: http://lkml.kernel.org/r/1408133138-22048-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-08 08:17:00 +02:00
Johannes Berg
787d6c1f17 iwlwifi: mvm: BT Coex - remove shadowing variable
The variable 'u32 mode' exists twice, the latter shadowing
the former - remove the latter since there's no need for
two variables.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
2014-09-08 09:16:55 +03:00
Daniel Vetter
4868b45de1 drm/i915: Fix irq enable tracking in driver load
A bunch of warnings fire on some ->irq_postinstall hooks since those
can enable interrupts (e.g. rps interrupts). And then our ordering
self-checks fire and complain.

To fix that set the tracking boolen before enabling the irqs with
drm_irq_install. Quoting the discussion with Jesse why that's safe:

On Tue, Aug 26, 2014 at 11:18 PM, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> Yes, it might work, but if you look through the history, we set this
> field carefully; first to true in the irq_init code, then to false only
> after the irq_install completes.  So I think your fragility arguments
> apply to this change too.

Well we've done it in 4 commits or so, but currently we have:

- Set irqs_disabled to true early in driver load to make sure checks
that. That's done in irq_init, which is totally not the function that
enables interrupts, only the function that initializes all the vtables
and similar things. We actually have a fairly sane naming scheme
nowadays (not fully consistent ofc): _init is sw setup,
_enable/_hw_init is the actual hw setup. That is done in
95f25beddb

- Set irqs_disabled to false right after the irqs are actually
enabled. This is done in ed2e6df189

So my change should only move the flag change over the ->preinstall
and ->postinstall hooks. I've done a little audit and didn't spot
anything amiss. Furthermore the runtime pm setup already clears
irqs_disabled _before_ calling these two hooks.

This regression has been introduced in

commit ed2e6df189
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Fri Jun 20 09:39:36 2014 -0700

    drm/i915: clear pm._irqs_disabled field after installing IRQs

Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk> # gm45, ilk
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2014-09-08 09:15:04 +03:00
Ingo Molnar
e2627dce26 Linux 3.17-rc4
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Merge tag 'v3.17-rc4' into sched/core, to prevent conflicts with upcoming patches, and to refresh the tree

Linux 3.17-rc4
2014-09-08 08:11:34 +02:00
Daniel Vetter
2232f0315c drm/i915: Fix EIO/wedged handling in gem fault handler
In

commit 1f83fee08d
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Nov 15 17:17:22 2012 +0100

    drm/i915: clear up wedged transitions

I've accidentally inverted the EIO/wedged handling in the fault
handler: We want to return the EIO as a SIGBUS only if it's not
because of the gpu having died, to prevent userspace from unduly
dying.

In my defence the comment right above is completely misleading, so fix
both.

v2: Drop the WARN_ON, it's not actually a bug to e.g. receive an -EIO
when swap-in fails.

v3: Don't remove too much ... oops.

Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2014-09-08 08:38:50 +03:00
Chris Wilson
ad46cb533d drm/i915: Prevent recursive deadlock on releasing a busy userptr
During release of the GEM object we hold the struct_mutex. As the
object may be holding onto the last reference for the task->mm,
calling mmput() may trigger exit_mmap() which close the vma
which will call drm_gem_vm_close() and attempt to reacquire
the struct_mutex. In order to avoid that recursion, we have
to defer the mmput() until after we drop the struct_mutex,
i.e. we need to schedule a worker to do the clean up. A further issue
spotted by Tvrtko was caused when we took a GTT mmapping of a userptr
buffer object. In that case, we would never call mmput as the object
would be cyclically referenced by the GTT mmapping and not freed upon
process exit - keeping the entire process mm alive after the process
task was reaped. The fix employed is to replace the mm_users/mmput()
reference handling to mm_count/mmdrop() for the shared i915_mm_struct.

   INFO: task test_surfaces:1632 blocked for more than 120 seconds.
         Tainted: GF          O 3.14.5+ #1
   "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
   test_surfaces   D 0000000000000000     0  1632   1590 0x00000082
    ffff88014914baa8 0000000000000046 0000000000000000 ffff88014914a010
    0000000000012c40 0000000000012c40 ffff8800a0058210 ffff88014784b010
    ffff88014914a010 ffff880037b1c820 ffff8800a0058210 ffff880037b1c824
   Call Trace:
    [<ffffffff81582499>] schedule+0x29/0x70
    [<ffffffff815825fe>] schedule_preempt_disabled+0xe/0x10
    [<ffffffff81583b93>] __mutex_lock_slowpath+0x183/0x220
    [<ffffffff81583c53>] mutex_lock+0x23/0x40
    [<ffffffffa005c2a3>] drm_gem_vm_close+0x33/0x70 [drm]
    [<ffffffff8115a483>] remove_vma+0x33/0x70
    [<ffffffff8115a5dc>] exit_mmap+0x11c/0x170
    [<ffffffff8104d6eb>] mmput+0x6b/0x100
    [<ffffffffa00f44b9>] i915_gem_userptr_release+0x89/0xc0 [i915]
    [<ffffffffa00e6706>] i915_gem_free_object+0x126/0x250 [i915]
    [<ffffffffa005c06a>] drm_gem_object_free+0x2a/0x40 [drm]
    [<ffffffffa005cc32>] drm_gem_object_handle_unreference_unlocked+0xe2/0x120 [drm]
    [<ffffffffa005ccd4>] drm_gem_object_release_handle+0x64/0x90 [drm]
    [<ffffffff8127ffeb>] idr_for_each+0xab/0x100
    [<ffffffffa005cc70>] ?  drm_gem_object_handle_unreference_unlocked+0x120/0x120 [drm]
    [<ffffffff81583c46>] ? mutex_lock+0x16/0x40
    [<ffffffffa005c354>] drm_gem_release+0x24/0x40 [drm]
    [<ffffffffa005b82b>] drm_release+0x3fb/0x480 [drm]
    [<ffffffff8118d482>] __fput+0xb2/0x260
    [<ffffffff8118d6de>] ____fput+0xe/0x10
    [<ffffffff8106f27f>] task_work_run+0x8f/0xf0
    [<ffffffff81052228>] do_exit+0x1a8/0x480
    [<ffffffff81052551>] do_group_exit+0x51/0xc0
    [<ffffffff810525d7>] SyS_exit_group+0x17/0x20
    [<ffffffff8158e092>] system_call_fastpath+0x16/0x1b

v2: Incorporate feedback from Tvrtko and remove the unnessary mm
referencing when creating the i915_mm_struct and improve some of the
function names and comments.

Reported-by: Jacek Danecki <jacek.danecki@intel.com>
Test-case: igt/gem_userptr_blits/process-exit*
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: "Gong, Zhipeng" <zhipeng.gong@intel.com>
Cc: Jacek Danecki <jacek.danecki@intel.com>
Cc: "Ursulin, Tvrtko" <tvrtko.ursulin@intel.com>
Reviewed-by: "Ursulin, Tvrtko" <tvrtko.ursulin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org # hold off until 3.17 ships for additional testing
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2014-09-08 08:38:49 +03:00
David S. Miller
eb84d6b604 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-09-07 21:41:53 -07:00
Linus Torvalds
d030671f3f Merge branch 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
 "This pull request includes Alban's patch to disallow '\n' in cgroup
  names.

  Two other patches from Li to fix a possible oops when cgroup
  destruction races against other file operations and one from Vivek to
  fix a unified hierarchy devel behavior"

* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: check cgroup liveliness before unbreaking kernfs
  cgroup: delay the clearing of cgrp->kn->priv
  cgroup: Display legacy cgroup files on default hierarchy
  cgroup: reject cgroup names with '\n'
2014-09-07 20:20:16 -07:00
Linus Torvalds
6a5c75ce10 Merge branch 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu fixes from Tejun Heo:
 "One patch to fix a failure path in the alloc path.  The bug is
  dangerous but probably not too likely to actually trigger in the wild
  given that there hasn't been any report yet.

  The other two are low impact fixes"

* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: free percpu allocation info for uniprocessor system
  percpu: perform tlb flush after pcpu_map_pages() failure
  percpu: fix pcpu_alloc_pages() failure path
2014-09-07 20:10:06 -07:00
Linus Torvalds
cfa7c641de Merge branch 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata
Pull libata fixes from Tejun Heo:
 "Two patches are to add PCI IDs for ICH9 and all others are device
  specific fixes.  Nothing too interesting"

* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  ahci_xgene: Fix the link down in first attempt for the APM X-Gene SoC AHCI SATA host controller driver.
  ahci_xgene: Skip the PHY and clock initialization if already configured by the firmware.
  ahci: add pcid for Marvel 0x9182 controller
  ata: Disabling the async PM for JMicron chip 363/361
  ata_piix: Add Device IDs for Intel 9 Series PCH
  ahci: Add Device IDs for Intel 9 Series PCH
  ata: ahci_tegra: Read calibration fuse
2014-09-07 20:06:44 -07:00
Linus Torvalds
b531f5dd9c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Fix skb leak in mac802154, from Martin Townsend

 2) Use select not depends on NF_NAT for NFT_NAT, from Pablo Neira
    Ayuso

 3) Fix union initializer bogosity in vxlan, from Gerhard Stenzel

 4) Fix RX checksum configuration in stmmac driver, from Giuseppe
    CAVALLARO

 5) Fix TSO with non-accelerated VLANs in e1000, e1000e, bna, ehea,
    i40e, i40evf, mvneta, and qlge, from Vlad Yasevich

 6) Fix capability checks in phy_init_eee(), from Giuseppe CAVALLARO

 7) Try high order allocations more sanely for SKBs, specifically if a
    high order allocation fails, fall back directly to zero order pages
    rather than iterating down one order at a time.  From Eric Dumazet

 8) Fix a memory leak in openvswitch, from Li RongQing

 9) amd-xgbe initializes wrong spinlock, from Thomas Lendacky

10) RTNL locking was busted in setsockopt for anycast and multicast, fix
    from Sabrina Dubroca

11) Fix peer address refcount leak in ipv6, from Nicolas Dichtel

12) DocBook typo fixes, from Masanari Iida

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (101 commits)
  ipv6: restore the behavior of ipv6_sock_ac_drop()
  amd-xgbe: Enable interrupts for all management counters
  amd-xgbe: Treat certain counter registers as 64 bit
  greth: moved TX ring cleaning to NAPI rx poll func
  cnic : Cleanup CONFIG_IPV6 & VLAN check
  net: treewide: Fix typo found in DocBook/networking.xml
  bnx2x: Fix link problems for 1G SFP RJ45 module
  3c59x: avoid panic in boomerang_start_xmit when finding page address:
  netfilter: add explicit Kconfig for NETFILTER_XT_NAT
  ipv6: use addrconf_get_prefix_route() to remove peer addr
  ipv6: fix a refcnt leak with peer addr
  net-timestamp: only report sw timestamp if reporting bit is set
  drivers/net/fddi/skfp/h/skfbi.h: Remove useless PCI_BASE_2ND macros
  l2tp: fix race while getting PMTU on PPP pseudo-wire
  ipv6: fix rtnl locking in setsockopt for anycast and multicast
  VMXNET3: Check for map error in vmxnet3_set_mc
  openvswitch: distinguish between the dropped and consumed skb
  amd-xgbe: Fix initialization of the wrong spin lock
  openvswitch: fix a memory leak
  netfilter: fix missing dependencies in NETFILTER_XT_TARGET_LOG
  ...
2014-09-07 19:56:38 -07:00
Tejun Heo
a34375ef9e percpu-refcount: add @gfp to percpu_ref_init()
Percpu allocator now supports allocation mask.  Add @gfp to
percpu_ref_init() so that !GFP_KERNEL allocation masks can be used
with percpu_refs too.

This patch doesn't make any functional difference.

v2: blk-mq conversion was missing.  Updated.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Jens Axboe <axboe@kernel.dk>
2014-09-08 09:51:30 +09:00
Tejun Heo
20ae00792c proportions: add @gfp to init functions
Percpu allocator now supports allocation mask.  Add @gfp to
[flex_]proportions init functions so that !GFP_KERNEL allocation masks
can be used with them too.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
2014-09-08 09:51:30 +09:00
Tejun Heo
908c7f1949 percpu_counter: add @gfp to percpu_counter_init()
Percpu allocator now supports allocation mask.  Add @gfp to
percpu_counter_init() so that !GFP_KERNEL allocation masks can be used
with percpu_counters too.

We could have left percpu_counter_init() alone and added
percpu_counter_init_gfp(); however, the number of users isn't that
high and introducing _gfp variants to all percpu data structures would
be quite ugly, so let's just do the conversion.  This is the one with
the most users.  Other percpu data structures are a lot easier to
convert.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: x86@kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
2014-09-08 09:51:29 +09:00
Tejun Heo
ebd8fef304 percpu_counter: make percpu_counters_lock irq-safe
percpu_counter is scheduled to grow @gfp support to allow atomic
initialization.  This patch makes percpu_counters_lock irq-safe so
that it can be safely used from atomic contexts.

Signed-off-by: Tejun Heo <tj@kernel.org>
2014-09-08 09:51:29 +09:00
Paul E. McKenney
284a8c93af rcu: Per-CPU operation cleanups to rcu_*_qs() functions
The rcu_bh_qs(), rcu_preempt_qs(), and rcu_sched_qs() functions use
old-style per-CPU variable access and write to ->passed_quiesce even
if it is already set.  This commit therefore updates to use the new-style
per-CPU variable access functions and avoids the spurious writes.
This commit also eliminates the "cpu" argument to these functions because
they are always invoked on the indicated CPU.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:35 -07:00
Paul E. McKenney
1d082fd061 rcu: Remove local_irq_disable() in rcu_preempt_note_context_switch()
The rcu_preempt_note_context_switch() function is on a scheduling fast
path, so it would be good to avoid disabling irqs.  The reason that irqs
are disabled is to synchronize process-level and irq-handler access to
the task_struct ->rcu_read_unlock_special bitmask.  This commit therefore
makes ->rcu_read_unlock_special instead be a union of bools with a short
allowing single-access checks in RCU's __rcu_read_unlock().  This results
in the process-level and irq-handler accesses being simple loads and
stores, so that irqs need no longer be disabled.  This commit therefore
removes the irq disabling from rcu_preempt_note_context_switch().

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:34 -07:00
Paul E. McKenney
4ff475ed4c rcu: Additional information on RCU-tasks stall-warning messages
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:33 -07:00
Paul E. McKenney
01a8133034 rcu: Remove redundant preempt_disable() from rcu_note_voluntary_context_switch()
In theory, synchronize_sched() requires a read-side critical section
to order against.  In practice, preemption can be thought of as
being disabled across every machine instruction, at least for those
machine instructions that are not in the idle loop and not on offline
CPUs.  So this commit removes the redundant preempt_disable() from
rcu_note_voluntary_context_switch().

Please note that the single instruction in question is the store of
zero to ->rcu_tasks_holdout.  The "if" is simply a performance optimization
that avoids unnecessary stores.  To see this, keep in mind that both
the "if" condition and the store are in a quiescent state.  Therefore,
even if the task is preempted for a full grace period (presumably due
to its having done a context switch beforehand), the store will be
recording a legitimate quiescent state.

Reported-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Conflicts:
	include/linux/rcupdate.h
2014-09-07 16:27:32 -07:00
Paul E. McKenney
8f20a5e83d rcu: Make rcu_tasks_kthread()'s GP-wait loop allow preemption
The grace-period-wait loop in rcu_tasks_kthread() is under (unnecessary)
RCU protection, and therefore has no preemption points in a PREEMPT=n
kernel.  This commit therefore removes the RCU protection and inserts
cond_resched().

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:31 -07:00
Paul E. McKenney
176f8f7a52 rcu: Make TASKS_RCU handle nohz_full= CPUs
Currently TASKS_RCU would ignore a CPU running a task in nohz_full=
usermode execution.  There would be neither a context switch nor a
scheduling-clock interrupt to tell TASKS_RCU that the task in question
had passed through a quiescent state.  The grace period would therefore
extend indefinitely.  This commit therefore makes RCU's dyntick-idle
subsystem record the task_struct structure of the task that is running
in dyntick-idle mode on each CPU.  The TASKS_RCU grace period can
then access this information and record a quiescent state on
behalf of any CPU running in dyntick-idle usermode.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:30 -07:00
Paul E. McKenney
84a8f446ff rcu: Defer rcu_tasks_kthread() creation till first call_rcu_tasks()
It is expected that many sites will have CONFIG_TASKS_RCU=y, but
will never actually invoke call_rcu_tasks().  For such sites, creating
rcu_tasks_kthread() at boot is wasteful.  This commit therefore defers
creation of this kthread until the time of the first call_rcu_tasks().

This of course means that the first call_rcu_tasks() must be invoked
from process context after the scheduler is fully operational.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:29 -07:00
Paul E. McKenney
37fe5f0e27 documentation: Add verbiage on RCU-tasks stall warning messages
This commit documents RCU-tasks stall warning messages and also describes
when to use the new cond_resched_rcu_qs() API.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:28 -07:00
Paul E. McKenney
c7b24d2b9a rcu: Improve RCU-tasks energy efficiency
The current RCU-tasks implementation uses strict polling to detect
callback arrivals.  This works quite well, but is not so good for
energy efficiency.  This commit therefore replaces the strict polling
with a wait queue.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:27 -07:00
Paul E. McKenney
52db30ab23 rcu: Add stall-warning checks for RCU-tasks
This commit adds a ten-minute RCU-tasks stall warning.  The actual
time is controlled by the boot/sysfs parameter rcu_task_stall_timeout,
with values less than or equal to zero disabling the stall warnings.
The default value is ten minutes, which means that the tasks that have
not yet responded will get their stacks dumped every ten minutes, until
they pass through a voluntary context switch.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:27:26 -07:00