TREE_RCU assumes that CPU numbering is contiguous, but some users need
large holes in the numbering to better map to hardware layout. This patch
makes TREE_RCU (and TREE_PREEMPT_RCU) tolerate large holes in the CPU
numbering. However, NR_CPUS must still be greater than the largest
CPU number.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The existing RCU CPU stall-warning messages can be confusing, especially
in the case where one CPU detects a single other stalled CPU. In addition,
the console messages did not say which flavor of RCU detected the stall,
which can make it difficult to work out exactly what is causing the stall.
This commit improves these messages.
Requested-by: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Print boot-time messages if tracing is enabled, if fanout is set
to non-default values, if exact fanout is specified, if accelerated
dyntick-idle grace periods have been enabled, if RCU-lockdep is enabled,
if rcutorture has been boot-time enabled, if the CPU stall detector has
been disabled, or if four-level hierarchy has been enabled.
This is all for TREE_RCU and TREE_PREEMPT_RCU. TINY_RCU will be handled
separately, if at all.
Suggested-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current RCU CPU stall warnings remain enabled even after a panic
occurs, which some people have found to be a bit counterproductive.
This patch therefore uses a notifier to disable stall warnings once a
panic occurs.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The CPU_STALL_VERBOSE kernel configuration parameter was added to
2.6.34 to identify any preempted/blocked tasks that were preventing
the current grace period from completing when running preemptible
RCU. As is conventional for new configurations parameters, this
defaulted disabled. It is now time to enable it by default.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
TINY_RCU does not need rcu_scheduler_active unless CONFIG_DEBUG_LOCK_ALLOC.
So conditionally compile rcu_scheduler_active in order to slim down
rcutiny a bit more. Also gets rid of an EXPORT_SYMBOL_GPL, which is
responsible for most of the slimming.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The addition of preemptible RCU to treercu resulted in a bit of
confusion and inefficiency surrounding the handling of context switches
for RCU-sched and for RCU-preempt. For RCU-sched, a context switch
is a quiescent state, pure and simple, just like it always has been.
For RCU-preempt, a context switch is in no way a quiescent state, but
special handling is required when a task blocks in an RCU read-side
critical section.
However, the callout from the scheduler and the outer loop in ksoftirqd
still calls something named rcu_sched_qs(), whose name is no longer
accurate. Furthermore, when rcu_check_callbacks() notes an RCU-sched
quiescent state, it ends up unnecessarily (though harmlessly, aside
from the performance hit) enqueuing the current task if it happens to
be running in an RCU-preempt read-side critical section. This not only
increases the maximum latency of scheduler_tick(), it also needlessly
increases the overhead of the next outermost rcu_read_unlock() invocation.
This patch addresses this situation by separating the notion of RCU's
context-switch handling from that of RCU-sched's quiescent states.
The context-switch handling is covered by rcu_note_context_switch() in
general and by rcu_preempt_note_context_switch() for preemptible RCU.
This permits rcu_sched_qs() to handle quiescent states and only quiescent
states. It also reduces the maximum latency of scheduler_tick(), though
probably by much less than a microsecond. Finally, it means that tasks
within preemptible-RCU read-side critical sections avoid incurring the
overhead of queuing unless there really is a context switch.
Suggested-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Because synchronize_rcu_bh() is identical to synchronize_sched(),
make the former a static inline invoking the latter, saving the
overhead of an EXPORT_SYMBOL_GPL() and the duplicate code.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_scheduler_active check has been wrapped into the new
debug_lockdep_rcu_enabled() function, so update the comments to
reflect this new reality.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Offline CPUs are not in nohz_cpu_mask, but can be ignored when checking
for the last non-dyntick-idle CPU. This patch therefore only checks
online CPUs for not being dyntick idle, allowing fast entry into
full-system dyntick-idle state even when there are some offline CPUs.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Shrink the RCU_INIT_FLAVOR() macro by moving all but the initialization
of the ->rda[] array to rcu_init_one(). The call to rcu_init_one()
can then be moved to the end of the RCU_INIT_FLAVOR() macro, which is
required because rcu_boot_init_percpu_data(), which is now called from
rcu_init_one(), depends on the initialization of the ->rda[] array.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch adds a check to __rcu_pending() that does a local
set_need_resched() if the current CPU is holding up the current grace
period and if force_quiescent_state() will be called soon. The goal is
to reduce the probability that force_quiescent_state() will need to do
smp_send_reschedule(), which sends an IPI and is therefore more expensive
on most architectures.
Signed-off-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
There is no need to disable lockdep after an RCU lockdep splat,
so remove the debug_lockdeps_off() from lockdep_rcu_dereference().
To avoid repeated lockdep splats, use a static variable in the inlined
rcu_dereference_check() and rcu_dereference_protected() macros so that
a given instance splats only once, but so that multiple instances can
be detected per boot.
This is controlled by a new config variable CONFIG_PROVE_RCU_REPEATEDLY,
which is disabled by default. This provides the normal lockdep behavior
by default, but permits people who want to find multiple RCU-lockdep
splats per boot to easily do so.
Requested-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
commit 672917dcc7 ("cpuidle: menu governor: reduce latency on exit")
added an optimization, where the analysis on the past idle period moved
from the end of idle, to the beginning of the new idle.
Unfortunately, this optimization had a bug where it zeroed one key
variable for new use, that is needed for the analysis. The fix is
simple, zero the variable after doing the work from the previous idle.
During the audit of the code that found this issue, another issue was
also found; the ->measured_us data structure member is never set, a
local variable is always used instead.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Corrado Zoccolo <czoccolo@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://neil.brown.name/md:
md: restore ability of spare drives to spin down.
md/raid6: Fix raid-6 read-error correction in degraded state
* 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6:
pcmcia: fix compilation after 16bit state locking changes
pcmcia: order userspace suspend and resume requests
pcmcia: avoid pccard_validate_cis failure in resume callpath
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
blk-cgroup: Fix an RCU warning in blkiocg_create()
blk-cgroup: Fix RCU correctness warning in cfq_init_queue()
drbd: don't expose failed local READ to upper layers
Move initialization of the virtio framework before the initialization of
mtd, so that block2mtd can be used on virtio-based block devices.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=15644
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Fix RCU issues in the NFSv4 delegation code
NFSv4: Fix the locking in nfs_inode_reclaim_delegation()
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
ACPI: sleep: init_set_sci_en_on_resume for Dell Studio 155x
ACPI: fix acpi_hest_firmware_first_pci() caused oops
sbshc: acpi_device_class "smbus_host_controller" too long
power_meter: acpi_device_class "power_meter_resource" too long
acpi_pad: "processor_aggregator" name too long
PNP: don't check for conflicts with bridge windows
ACPI: DMI init_set_sci_en_on_resume for multiple Lenovo ThinkPads
PNPACPI: compute Address Space length rather than using _LEN
ACPI: silence kmemcheck false positive
* 'v4l_for_2.6.34' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6:
V4L/DVB: pxa_camera: move fifo reset direct before dma start
V4L/DVB: video: testing unsigned for less than 0
V4L/DVB: mx1-camera: compile fix
V4L/DVB: budget: Oops: "BUG: unable to handle kernel NULL pointer dereference"
V4L/DVB: ngene: Workaround for stuck DiSEqC pin
V4L/DVB: saa7146: fix regression of the av7110/budget-av driver
V4L/DVB: v4l: fix config dependencies: mxb and saa7191 are V4L2 drivers, not V4L1
V4L/DVB: feature-removal: announce videotext.h removal
V4L/DVB: V4L - vpfe capture - fix for kernel crash
V4L/DVB: gspca: make usb id 0461:0815 get handled by the right driver
V4L/DVB: gspca - stv06xx: Remove the 046d:08da from the stv06xx driver
V4L/DVB: gspca - sn9c20x: Correct onstack wait_queue_head declaration
V4L/DVB: saa7146: fix up bytesperline if it is an impossible value
V4L/DVB: V4L: vpfe_capture - free ccdc_lock when memory allocation fails
V4L/DVB: V4L - Makfile:Removed duplicate entry of davinci
V4L/DVB: omap24xxcam: potential buffer overflow
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: create rcu_my_thread_group_empty() wrapper
memcg: css_id() must be called under rcu_read_lock()
cgroup: Check task_lock in task_subsys_state()
sched: Fix an RCU warning in print_task()
cgroup: Fix an RCU warning in alloc_css_id()
cgroup: Fix an RCU warning in cgroup_path()
KEYS: Fix an RCU warning in the reading of user keys
KEYS: Fix an RCU warning
Some time ago we stopped the clean/active metadata updates
from being written to a 'spare' device in most cases so that
it could spin down and say spun down. Device failure/removal
etc are still recorded on spares.
However commit 51d5668cb2 broke this 50% of the time,
depending on whether the event count is even or odd.
The change log entry said:
This means that the alignment between 'odd/even' and
'clean/dirty' might take a little longer to attain,
how ever the code makes no attempt to create that alignment, so it
could take arbitrarily long.
So when we find that clean/dirty is not aligned with odd/even,
force a second metadata-update immediately. There are already cases
where a second metadata-update is needed immediately (e.g. when a
device fails during the metadata update). We just piggy-back on that.
Reported-by: Joe Bryant <tenminjoe@yahoo.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
Fix: Raid-6 was not trying to correct a read-error when in
singly-degraded state and was instead dropping one more device, going to
doubly-degraded state. This patch fixes this behaviour.
Tested-by: Janos Haar <janos.haar@netcenter.hu>
Signed-off-by: Gabriele A. Trombetti <g.trombetti.lkrnl1213@logicschema.com>
Reported-by: Janos Haar <janos.haar@netcenter.hu>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
with CONFIG_PROVE_RCU=y, a warning can be triggered:
# mount -t cgroup -o blkio xxx /mnt
# mkdir /mnt/subgroup
...
kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection!
...
To fix this, we avoid caling css_depth() here, which is a bit simpler
than the original code.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
It's unused and buggy in its current form, since it can place a bo
in the reserved state without removing it from lru lists.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Bring radeon up to speed with the async event synchronization for
drmWaitVblank. See c9a9c5e02a for
more information. Without this patch event never get delivered
to userspace client.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Move the fifo reset from pxa_camera_start_capture to pxa_camera_irq direct
before the dma start after an end of frame interrupt to prevent images from
shifting because of old data at the begin of the frame.
Signed-off-by: Stefan Herbrechtsmeier <hbmeier@hni.uni-paderborn.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Tested-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
soc_mbus_bytes_per_line() returns -EINVAL on error but we store it in an
unsigned int so the test for less than zero doesn't work. I think it
always returns "small" positive values so we can just cast it to int
here.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This fixes a regression of
7d58289 (mx1: prefix SOC specific defines with MX1_ and deprecate old names)
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Never call dvb_frontend_detach if we failed to attach a frontend. This fixes
the following oops, which will be triggered by a missing stv090x module:
[ 8.172997] DVB: registering new adapter (TT-Budget S2-1600 PCI)
[ 8.209018] adapter has MAC addr = 00:d0:5c:cc:a7:29
[ 8.328665] Intel ICH 0000:00:1f.5: PCI INT B -> GSI 17 (level, low) -> IRQ 17
[ 8.328753] Intel ICH 0000:00:1f.5: setting latency timer to 64
[ 8.562047] DVB: Unable to find symbol stv090x_attach()
[ 8.562117] BUG: unable to handle kernel NULL pointer dereference at 000000ac
[ 8.562239] IP: [<e08b04a3>] dvb_frontend_detach+0x4/0x67 [dvb_core]
Ref http://bugs.debian.org/575207
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: stable@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Send one DiSEqC byte to make sure that the pin is set to low level.
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Reviewed-by: Manu Abraham <abraham.manu@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
An earlier regression fix for the mxb driver (V4L/DVB: saa7146_vv: fix
regression where v4l2_device was registered too late) caused a new
regression in the av7110 driver.
Reverted the old fix and fixed the problem in the mxb driver instead.
Tested on mxb and budget-av cards.
The real problem is that the saa7146 framework has separate probe()
and attach() driver callbacks which should be rolled into one. This
is now done for the mxb driver, but others should do the same. Lack
of hardware makes this hard to do, though. I hope to get hold of some
hexium cards and then I can try to improve the framework to prevent
this from happening again.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
As part of upstream merge, set_params() function was removed from isif.c.
This requires removal of BUG_ON() and check for set_params ptr in
vpfe_capture.c. Without this kernel crash dump is seen while bootup on DM365
Also made following changes:-
1) converted error messages to debug messages since it is not right to flood
the console with error messages for user mistakes.
2) returns -EINVAL if ioctl is not supported
Signed-off-by: Muralidharan Karicheri <m-karicheri2@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The 0461:0815 camera is spca561 based not spca508
Signed-off-by: John Ellson <john.ellson@comcast.net>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The 046d:08da usb id shouldn't be associated with the stv06xx driver as they're
not compatible with each other.
This fixes a bug where Quickcam Messenger cams fail to use its proper driver
(gspca-zc3xx), rendering the camera inoperable.
Signed-off-by: Erik Andrén <erik.andren@gmail.com>
Tested-by: Gabriel Craciunescu <nix.or.die@googlemail.com>
Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Use DECLARE_WAIT_QUEUE_HEAD_ONSTACK to make lockdep happy
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Jean-François Moine <moinejf@free.fr>
CC: Brian Johnson <brijohn@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
xawtv using DGA on a Radeon graphics card provides bogus
values to S_FBUF, which will then screw up overlay video:
https://bugs.launchpad.net/ubuntu/+source/xawtv/+bug/499734
This fixes the bytesperline value if it is off completely.
Signed-off-by: Michael Hunold <michael@mihu.de>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This patch fixes a bug in vpfe_probe() that doesn't call mutex_unlock() if memory
allocation for ccdc_cfg fails. See also the smatch warning report from Dan
Carpenter that shows this as an issue.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Paul E. McKenney