Commit graph

255084 commits

Author SHA1 Message Date
Vinod Koul
1ae105aa74 Merge branch 'next' into for-linus-3.0 2011-07-27 20:43:21 +05:30
Russell King - ARM Linux
5a42fb93e6 Improve slave/cyclic DMA engine documentation
Improve the documentation for the slave and cyclic DMA engine support
reformatting it for easier reading, adding further APIs, splitting it
into five steps, and including references to the documentation in
dmaengine.h.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[Fixed the index title to reflect new changes]
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-27 20:33:48 +05:30
Vinod Koul
f32807f1ff dmaengine: pl08x: handle the rest of enums in pl08x_width
pl08x_width function does not handle rest of enums for DMA_SLAVE_BUSWIDTH_xxxx
which causes gcc to emit below warining

drivers/dma/amba-pl08x.c: In function 'pl08x_width':
	drivers/dma/amba-pl08x.c:1119: warning: enumeration value
	'DMA_SLAVE_BUSWIDTH_UNDEFINED' not handled in switch
	drivers/dma/amba-pl08x.c:1119: warning: enumeration value
	'DMA_SLAVE_BUSWIDTH_8_BYTES' not handled in switch

this patch adds a default case which returns error

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:29 +05:30
Russell King - ARM Linux
760596c6b9 DMA: PL08x: cleanup selection of burst size
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:29 +05:30
Russell King - ARM Linux
121c8476a3 DMA: PL08x: avoid recalculating cctl at each prepare
Now that we have separate cctl values for M>P and P>M transfers, we can
avoid calculating the cctl value each time we prepare a transaction.
Move the bus selection and increment setting to the slave configuration
and initialization functions.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:29 +05:30
Russell King - ARM Linux
aa88cdaa14 DMA: PL08x: cleanup selection of buswidth
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Russell King - ARM Linux
fa020e7d04 DMA: PL08x: constify plchan->cd and plat->slave_channels
We no longer write to the channel data structure, so we can make it
const throughout the driver.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Russell King - ARM Linux
f14c426c72 DMA: PL08x: separately store source/destination cctl
Store the source/destination cctl values into the channel structure.
This moves us towards being able to avoid a configuration call each
time we use the channel.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Russell King - ARM Linux
b207b4d02b DMA: PL08x: separately store source/destination slave address
Store the source/destination slave address separately into the channel
structure.  This moves us towards being able to avoid a configuration
call each time we use the channel.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Russell King - ARM Linux
fc74eb7915 DMA: PL08x: clean up LLI debugging
Clean up debugging when setting up the LLI list.  This reduces the
amount of output while preserving the information, and makes it easier
to read.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Russell King - ARM Linux
25c94f7fcf DMA: PL08x: select LLI bus only once per LLI setup
Avoid re-selecting the LLI bus each time we create an LLI.  Move it out
of the LLI setup loops.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Russell King - ARM Linux
f44bd19140 DMA: PL08x: remove unused constants
PL08X_WQ_PERIODMIN and PL08X_MAX_ALLOCS are not used, remove them.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Dong Aisheng
a62bae98a9 ARM: mxs-dma: reset after disable channel
We met some channels in abnormal state after disable.
Reset it to get a clean state.

Signed-off-by: Dong Aisheng <b29396@freescale.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:28 +05:30
Axel Lin
add56ba711 dma: intel_mid_dma: remove redundant pci_set_drvdata calls
Call pci_set_drvdata() once in intel_mid_dma_probe() is enough.
Remove redundant pci_set_drvdata() calls in dma_suspend() and dma_resume().

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:27 +05:30
Axel Lin
2a9778ed83 dma: mxs-dma: fix unterminated platform_device_id table
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:33:27 +05:30
Rob Herring
4e0e6109a1 dmaengine: pl330: make platform data optional
The pl330 needs platform data for describing peripheral connections, but
some platforms may only support memory to memory dma channels. In this
case, we can probe for how many channels there are and don't need the
platform data.

As memcpy requests don't need channel private data to hold peripheral
info, allow private data to be NULL in this case.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Jassi Brar <jassisinghbrar@gmail.com>
Cc: Vinod Koul <vkoul@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-26 15:32:52 +05:30
Axel Lin
1c1d954753 dmaengine: imx-sdma: return proper error if kzalloc fails
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-25 19:11:12 +05:30
Tomoya MORINAGA
0b052f4a08 pch_dma: Fix CTL register access issue
Currently, Mode-Control register is accessed by read-modify-write.

According to DMA hardware specifications datasheet, prohibits this method.
Because this register resets to 0 by DMA HW after DMA transfer completes.
Thus, current read-modify-write processing can cause unexpected behavior.

The datasheet says in case of writing Mode-Control register, set the value for only target channel, the others must set '11b'.
e.g. Set DMA0=01b  DMA11=10b
CTL0=33333331h
CTL2=00002333h

NOTE:
CTL0 includes DMA0~7 Mode-Control register.
CTL2 includes DMA8~11 Mode-Control register.

This patch modifies the issue.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2011-07-25 19:11:12 +05:30
Linus Torvalds
02f8c6aee8 Linux 3.0 2011-07-21 19:17:23 -07:00
Linus Torvalds
1f922d0770 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  sparc,kgdbts: fix compile regression with kgdb test suite
2011-07-21 17:20:57 -07:00
Jason Wessel
33d8881af5 sparc,kgdbts: fix compile regression with kgdb test suite
Commit 63ab25ebbc (kgdbts: unify/generalize gdb breakpoint adjustment)
introduced a compile regression on sparc.

kgdbts.c: In function 'check_and_rewind_pc':
kgdbts.c:307: error: implicit declaration of function 'instruction_pointer_set'

Simply add the correct macro definition for instruction pointer on the
Sparc architecture.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: David S. Miller <davem@davemloft.net>
2011-07-21 17:29:49 -05:00
Linus Torvalds
2bafc7a275 Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  CIFS: Fix wrong length in cifs_iovec_read
2011-07-21 14:28:01 -07:00
Linus Torvalds
57a6fa9acd Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Make Dell Latitude E6420 use reboot=pci
  x86: Make Dell Latitude E5420 use reboot=pci
2011-07-21 12:25:39 -07:00
H. Peter Anvin
a536877e77 x86: Make Dell Latitude E6420 use reboot=pci
Yet another variant of the Dell Latitude series which requires
reboot=pci.

From the E5420 bug report by Daniel J Blueman:

> The E6420 is affected also (same platform, different casing and
> features), which provides an external confirmation of the issue; I can
> submit a patch for that later or include it if you prefer:
> http://linux.koolsolutions.com/2009/08/04/howto-fix-linux-hangfreeze-during-reboots-and-restarts/

Reported-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>
2011-07-21 11:47:17 -07:00
Daniel J Blueman
b7798d28ec x86: Make Dell Latitude E5420 use reboot=pci
Rebooting on the Dell E5420 often hangs with the keyboard or ACPI
methods, but is reliable via the PCI method.

[ hpa: this was deferred because we believed for a long time that the
  recent reshuffling of the boot priorities in commit
  660e34cebf fixed this platform.
  Unfortunately that turned out to be incorrect. ]

Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Link: http://lkml.kernel.org/r/1305248699-2347-1-git-send-email-daniel.blueman@gmail.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>
2011-07-21 11:45:49 -07:00
Linus Torvalds
ad21b11577 Merge branch 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/keithp/linux-2.6
* 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/keithp/linux-2.6:
  drm/i915: Fix unfenced alignment on pre-G33 hardware
  drm/i915: Add quirk to disable SSC on Lenovo U160 LVDS
2011-07-21 11:07:18 -07:00
Linus Torvalds
b91da88fed vfs: drop conditional inode prefetch in __do_lookup_rcu
It seems to hurt performance in real life.  Yes, the inode will be used
later, but the conditional doesn't seem to predict all that well
(negative dentries are not uncommon) and it looks like the cost of
prefetching is simply higher than depending on the cache doing the right
thing.

As usual.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-21 11:01:42 -07:00
Jan Beulich
b307d4655a FS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loop
The compiler, at least for ix86 and m68k, validly warns that the
comparison:

	next <= (loff_t)-1

is always true (and it's always true also for x86-64 and probably all
other arches - as long as pgoff_t isn't wider than loff_t).  The
intention appears to be to avoid wrapping of "next", so rather than
eliminating the pointless comparison, fix the loop to indeed get exited
when "next" would otherwise wrap.

On m68k the following warning is observed:

  fs/fscache/page.c: In function '__fscache_uncache_all_inode_pages':
  fs/fscache/page.c:979: warning: comparison is always false due to limited range of data type

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Suresh Jayaraman <sjayaraman@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-21 10:59:16 -07:00
Pavel Shilovsky
2cebaa58b7 CIFS: Fix wrong length in cifs_iovec_read
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-07-21 00:48:05 +00:00
Linus Torvalds
cf6ace16a3 Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  signal: align __lock_task_sighand() irq disabling and RCU
  softirq,rcu: Inform RCU of irq_exit() activity
  sched: Add irq_{enter,exit}() to scheduler_ipi()
  rcu: protect __rcu_read_unlock() against scheduler-using irq handlers
  rcu: Streamline code produced by __rcu_read_unlock()
  rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special
  rcu: decrease rcu_report_exp_rnp coupling with scheduler
2011-07-20 15:56:25 -07:00
Linus Torvalds
acc11eab70 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Avoid creating superfluous NUMA domains on non-NUMA systems
  sched: Allow for overlapping sched_domain spans
  sched: Break out cpu_power from the sched_group structure
2011-07-20 15:55:48 -07:00
Linus Torvalds
919d25a710 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86. reboot: Make Dell Latitude E6320 use reboot=pci
  x86, doc only: Correct real-mode kernel header offset for init_size
  x86: Disable AMD_NUMA for 32bit for now
2011-07-20 15:33:59 -07:00
Ingo Molnar
d1e9ae47a0 Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/urgent 2011-07-20 20:59:26 +02:00
Paul E. McKenney
a841796f11 signal: align __lock_task_sighand() irq disabling and RCU
The __lock_task_sighand() function calls rcu_read_lock() with interrupts
and preemption enabled, but later calls rcu_read_unlock() with interrupts
disabled.  It is therefore possible that this RCU read-side critical
section will be preempted and later RCU priority boosted, which means that
rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but
with interrupts disabled. This results in lockdep splats, so this commit
nests the RCU read-side critical section within the interrupt-disabled
region of code.  This prevents the RCU read-side critical section from
being preempted, and thus prevents the attempt to deboost with interrupts
disabled.

It is quite possible that a better long-term fix is to make rt_mutex_unlock()
disable irqs when acquiring the rt_mutex structure's ->wait_lock.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20 11:04:54 -07:00
Peter Zijlstra
ec433f0c51 softirq,rcu: Inform RCU of irq_exit() activity
The rcu_read_unlock_special() function relies on in_irq() to exclude
scheduler activity from interrupt level.  This fails because exit_irq()
can invoke the scheduler after clearing the preempt_count() bits that
in_irq() uses to determine that it is at interrupt level.  This situation
can result in failures as follows:

 $task			IRQ		SoftIRQ

 rcu_read_lock()

 /* do stuff */

 <preempt> |= UNLOCK_BLOCKED

 rcu_read_unlock()
   --t->rcu_read_lock_nesting

			irq_enter();
			/* do stuff, don't use RCU */
			irq_exit();
			  sub_preempt_count(IRQ_EXIT_OFFSET);
			  invoke_softirq()

					ttwu();
					  spin_lock_irq(&pi->lock)
					  rcu_read_lock();
					  /* do stuff */
					  rcu_read_unlock();
					    rcu_read_unlock_special()
					      rcu_report_exp_rnp()
					        ttwu()
					          spin_lock_irq(&pi->lock) /* deadlock */

   rcu_read_unlock_special(t);

Ed can simply trigger this 'easy' because invoke_softirq() immediately
does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff
first, but even without that the above happens.

Cure this by also excluding softirqs from the
rcu_read_unlock_special() handler and ensuring the force_irqthreads
ksoftirqd/# wakeup is done from full softirq context.

[ Alternatively, delaying the ->rcu_read_lock_nesting decrement
  until after the special handling would make the thing more robust
  in the face of interrupts as well.  And there is a separate patch
  for that. ]

Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-and-tested-by: Ed Tomlinson <edt@aei.ca>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20 10:50:12 -07:00
Peter Zijlstra
c5d753a55a sched: Add irq_{enter,exit}() to scheduler_ipi()
Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual
work. Traditionally we never did any actual work from the resched IPI
and all magic happened in the return from interrupt path.

Now that we do do some work, we need to ensure irq_{enter,exit} are
called so that we don't confuse things.

This affects things like timekeeping, NO_HZ and RCU, basically
everything with a hook in irq_enter/exit.

Explicit examples of things going wrong are:

  sched_clock_cpu() -- has a callback when leaving NO_HZ state to take
                    a new reading from GTOD and TSC. Without this
                    callback, time is stuck in the past.

  RCU -- needs in_irq() to work in order to avoid some nasty deadlocks

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20 10:50:11 -07:00
Paul E. McKenney
10f39bb1b2 rcu: protect __rcu_read_unlock() against scheduler-using irq handlers
The addition of RCU read-side critical sections within runqueue and
priority-inheritance lock critical sections introduced some deadlock
cycles, for example, involving interrupts from __rcu_read_unlock()
where the interrupt handlers call wake_up().  This situation can cause
the instance of __rcu_read_unlock() invoked from interrupt to do some
of the processing that would otherwise have been carried out by the
task-level instance of __rcu_read_unlock().  When the interrupt-level
instance of __rcu_read_unlock() is called with a scheduler lock held
from interrupt-entry/exit situations where in_irq() returns false,
deadlock can result.

This commit resolves these deadlocks by using negative values of
the per-task ->rcu_read_lock_nesting counter to indicate that an
instance of __rcu_read_unlock() is in flight, which in turn prevents
instances from interrupt handlers from doing any special processing.
This patch is inspired by Steven Rostedt's earlier patch that similarly
made __rcu_read_unlock() guard against interrupt-mediated recursion
(see https://lkml.org/lkml/2011/7/15/326), but this commit refines
Steven's approach to avoid the need for preemption disabling on the
__rcu_read_unlock() fastpath and to also avoid the need for manipulating
a separate per-CPU variable.

This patch avoids need for preempt_disable() by instead using negative
values of the per-task ->rcu_read_lock_nesting counter.  Note that nested
rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will
never see ->rcu_read_lock_nesting go to zero, and will therefore never
invoke rcu_read_unlock_special(), thus preventing them from seeing the
RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special.
This patch also adds a check for ->rcu_read_unlock_special being negative
in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS
bit from being set should a scheduling-clock interrupt occur while
__rcu_read_unlock() is exiting from an outermost RCU read-side critical
section.

Of course, __rcu_read_unlock() can be preempted during the time that
->rcu_read_lock_nesting is negative.  This could result in the setting
of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it,
and would also result it this task being queued on the corresponding
rcu_node structure's blkd_tasks list.  Therefore, some later RCU read-side
critical section would enter rcu_read_unlock_special() to clean up --
which could result in deadlock if that critical section happened to be in
the scheduler where the runqueue or priority-inheritance locks were held.

This situation is dealt with by making rcu_preempt_note_context_switch()
check for negative ->rcu_read_lock_nesting, thus refraining from
queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are
already exiting from the outermost RCU read-side critical section (in
other words, we really are no longer actually in that RCU read-side
critical section).  In addition, rcu_preempt_note_context_switch()
invokes rcu_read_unlock_special() to carry out the cleanup in this case,
which clears out the ->rcu_read_unlock_special bits and dequeues the task
(if necessary), in turn avoiding needless delay of the current RCU grace
period and needless RCU priority boosting.

It is still illegal to call rcu_read_unlock() while holding a scheduler
lock if the prior RCU read-side critical section has ever had either
preemption or irqs enabled.  However, the common use case is legal,
namely where then entire RCU read-side critical section executes with
irqs disabled, for example, when the scheduler lock is held across the
entire lifetime of the RCU read-side critical section.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-20 10:50:11 -07:00
Peter Zijlstra
d110235d2c sched: Avoid creating superfluous NUMA domains on non-NUMA systems
When creating sched_domains, stop when we've covered the entire
target span instead of continuing to create domains, only to
later find they're redundant and throw them away again.

This avoids single node systems from touching funny NUMA
sched_domain creation code and reduces the risks of the new
SD_OVERLAP code.

Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Anton Blanchard <anton@samba.org>
Cc: mahesh@linux.vnet.ibm.com
Cc: benh@kernel.crashing.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1311180177.29152.57.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-20 18:54:33 +02:00
Peter Zijlstra
e3589f6c81 sched: Allow for overlapping sched_domain spans
Allow for sched_domain spans that overlap by giving such domains their
own sched_group list instead of sharing the sched_groups amongst
each-other.

This is needed for machines with more than 16 nodes, because
sched_domain_node_span() will generate a node mask from the
16 nearest nodes without regard if these masks have any overlap.

Currently sched_domains have a sched_group that maps to their child
sched_domain span, and since there is no overlap we share the
sched_group between the sched_domains of the various CPUs. If however
there is overlap, we would need to link the sched_group list in
different ways for each cpu, and hence sharing isn't possible.

In order to solve this, allocate private sched_groups for each CPU's
sched_domain but have the sched_groups share a sched_group_power
structure such that we can uniquely track the power.

Reported-and-tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-08bxqw9wis3qti9u5inifh3y@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-20 18:32:41 +02:00
Peter Zijlstra
9c3f75cbd1 sched: Break out cpu_power from the sched_group structure
In order to prepare for non-unique sched_groups per domain, we need to
carry the cpu_power elsewhere, so put a level of indirection in.

Reported-and-tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-qkho2byuhe4482fuknss40ad@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-07-20 18:32:40 +02:00
Linus Torvalds
e6625fa48e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: fix file mode calculation
2011-07-19 22:10:28 -07:00
Linus Torvalds
47126d807a Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-arm-soc:
  davinci: DM365 EVM: fix video input mux bits
  ARM: davinci: Check for NULL return from irq_alloc_generic_chip
  arm: davinci: Fix low level gpio irq handlers' argument
2011-07-19 22:10:05 -07:00
Shaohua Li
4746efded8 vmscan: fix a livelock in kswapd
I'm running a workload which triggers a lot of swap in a machine with 4
nodes.  After I kill the workload, I found a kswapd livelock.  Sometimes
kswapd3 or kswapd2 are keeping running and I can't access filesystem,
but most memory is free.

This looks like a regression since commit 08951e5459 ("mm: vmscan:
correct check for kswapd sleeping in sleeping_prematurely").

Node 2 and 3 have only ZONE_NORMAL, but balance_pgdat() will return 0
for classzone_idx.  The reason is end_zone in balance_pgdat() is 0 by
default, if all zones have watermark ok, end_zone will keep 0.

Later sleeping_prematurely() always returns true.  Because this is an
order 3 wakeup, and if classzone_idx is 0, both balanced_pages and
present_pages in pgdat_balanced() are 0.  We add a special case here.
If a zone has no page, we think it's balanced.  This fixes the livelock.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-19 22:09:31 -07:00
Akinobu Mita
f7b88631a8 fs/libfs.c: fix simple_attr_write() on 32bit machines
Assume that /sys/kernel/debug/dummy64 is debugfs file created by
debugfs_create_x64().

	# cd /sys/kernel/debug
	# echo 0x1234567812345678 > dummy64
	# cat dummy64
	0x0000000012345678

	# echo 0x80000000 > dummy64
	# cat dummy64
	0xffffffff80000000

A value larger than INT_MAX cannot be written to the debugfs file created
by debugfs_create_u64 or debugfs_create_x64 on 32bit machine.  Because
simple_attr_write() uses simple_strtol() for the conversion.

To fix this, use simple_strtoll() instead.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-19 22:09:30 -07:00
Linus Torvalds
e501f29c72 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  vfs: fix race in rcu lookup of pruned dentry
  Fix cifs_get_root()

[ Edited the last commit to get rid of a 'unused variable "seq"'
  warning due to Al editing the patch.  - Linus ]
2011-07-19 21:50:21 -07:00
Linus Torvalds
5943026240 vfs: fix race in rcu lookup of pruned dentry
Don't update *inode in __follow_mount_rcu() until we'd verified that
there is mountpoint there.  Kudos to Hugh Dickins for catching that
one in the first place and eventually figuring out the solution (and
catching a braino in the earlier version of patch).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-19 21:49:01 -07:00
Paul E. McKenney
be0e1e21ef rcu: Streamline code produced by __rcu_read_unlock()
Given some common flag combinations, particularly -Os, gcc will inline
rcu_read_unlock_special() despite its being in an unlikely() clause.
Use noinline to prohibit this misoptimization.

In addition, move the second barrier() in __rcu_read_unlock() so that
it is not on the common-case code path.  This will allow the compiler to
generate better code for the common-case path through __rcu_read_unlock().

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
2011-07-19 21:38:53 -07:00
Paul E. McKenney
7765be2fec rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special
The RCU_BOOST commits for TREE_PREEMPT_RCU introduced an other-task
write to a new RCU_READ_UNLOCK_BOOSTED bit in the task_struct structure's
->rcu_read_unlock_special field, but, as noted by Steven Rostedt, without
correctly synchronizing all accesses to ->rcu_read_unlock_special.
This could result in bits in ->rcu_read_unlock_special being spuriously
set and cleared due to conflicting accesses, which in turn could result
in deadlocks between the rcu_node structure's ->lock and the scheduler's
rq and pi locks.  These deadlocks would result from RCU incorrectly
believing that the just-ended RCU read-side critical section had been
preempted and/or boosted.  If that RCU read-side critical section was
executed with either rq or pi locks held, RCU's ensuing (incorrect)
calls to the scheduler would cause the scheduler to attempt to once
again acquire the rq and pi locks, resulting in deadlock.  More complex
deadlock cycles are also possible, involving multiple rq and pi locks
as well as locks from multiple rcu_node structures.

This commit fixes synchronization by creating ->rcu_boosted field in
task_struct that is accessed and modified only when holding the ->lock
in the rcu_node structure on which the task is queued (on that rcu_node
structure's ->blkd_tasks list).  This results in tasks accessing only
their own current->rcu_read_unlock_special fields, making unsynchronized
access once again legal, and keeping the rcu_read_unlock() fastpath free
of atomic instructions and memory barriers.

The reason that the rcu_read_unlock() fastpath does not need to access
the new current->rcu_boosted field is that this new field cannot
be non-zero unless the RCU_READ_UNLOCK_BLOCKED bit is set in the
current->rcu_read_unlock_special field.  Therefore, rcu_read_unlock()
need only test current->rcu_read_unlock_special: if that is zero, then
current->rcu_boosted must also be zero.

This bug does not affect TINY_PREEMPT_RCU because this implementation
of RCU accesses current->rcu_read_unlock_special with irqs disabled,
thus preventing races on the !SMP systems that TINY_PREEMPT_RCU runs on.

Maybe-reported-by: Dave Jones <davej@redhat.com>
Maybe-reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
2011-07-19 21:38:52 -07:00
Paul E. McKenney
131906b006 rcu: decrease rcu_report_exp_rnp coupling with scheduler
PREEMPT_RCU read-side critical sections blocking an expedited grace
period invoke rcu_report_exp_rnp().  When the last such critical section
has completed, rcu_report_exp_rnp() invokes the scheduler to wake up the
task that invoked synchronize_rcu_expedited() -- needlessly holding the
root rcu_node structure's lock while doing so, thus needlessly providing
a way for RCU and the scheduler to deadlock.

This commit therefore releases the root rcu_node structure's lock before
calling wake_up().

Reported-by: Ed Tomlinson <edt@aei.ca>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-07-19 21:38:51 -07:00
Sage Weil
38be7a79f7 ceph: fix file mode calculation
open(2) must always include one of O_RDONLY, O_WRONLY, or O_RDWR.  No need
for any O_APPEND special case.

Passing O_WRONLY|O_RDWR is undefined according to the man page, but the
Linux VFS interprets this as O_RDWR, so we'll do the same.

This fixes open(2) with flags O_RDWR|O_APPEND, which was incorrectly being
translated to readonly.

Reported-by: Fyodor Ustinov <ufm@ufm.su>
Signed-off-by: Sage Weil <sage@newdream.net>
2011-07-19 11:25:04 -07:00