Add the CONFIG_DEBUG_STACKOVERFLOW config option to enable checks to
detect kernel stack overflows.
Stack overflows can not be detected reliable since we do not want to
introduce too much overhead.
Instead, during irq processing in do_cpu_irq_mask() we check kernel
stack usage of the interrupted kernel process. Kernel threads can be
easily detected by checking the value of space register 7 (sr7) which
is zero when running inside the kernel.
Since THREAD_SIZE is 16k and PAGE_SIZE is 4k, reduce the alignment of
the init thread to the lower value (PAGE_SIZE) in the kernel
vmlinux.ld.S linker script.
Signed-off-by: Helge Deller <deller@gmx.de>
arch/arm/mach-msm/last_radio_log.c: In function 'msm_init_last_radio_log':
arch/arm/mach-msm/last_radio_log.c:69:7: error: dereferencing pointer to incomplete type
arch/cris/kernel/profile.c: In function 'init_cris_profile':
arch/cris/kernel/profile.c:79:8: error: dereferencing pointer to incomplete type
Use proc_set_size(), cfr. commit 271a15eabe
("proc: Supply PDE attribute setting accessor functions")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Helge and I have found that we have a kernel stack overflow problem
which causes a variety of random failures.
Currently, we re-enable interrupts when returning from an external
interrupt incase we need to schedule or delivery
signals. As a result, a potentially unlimited number of interrupts
can occur while we are running on the kernel
stack. It is very limited in space (currently, 16k). This change
defers enabling interrupts until we have
actually decided to schedule or delivery signals. This only occurs
when we about to return to userspace. This
limits the number of interrupts on the kernel stack to one. In other
cases, interrupts remain disabled until the
final return from interrupt (rfi).
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Pull late ARM Exynos multiplatform changes from Arnd Bergmann:
"These continue the multiplatform support for exynos, adding support
for building most of the essential drivers (clocksource, clk, irqchip)
when combined with other platforms. As a result, it should become
really easy to add full multiplatform exynos support in 3.11, although
we don't yet enable it for 3.10.
The changes were not included in the earlier multiplatform series in
order to avoid clashes with the other Exynos updates.
This also includes work from Tomasz Figa to fix the pwm clocksource
code on Exynos, which is not strictly required for multiplatform, but
related to the other patches in this set and needed as a bug fix for
at least one board."
* tag 'multiplatform-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (22 commits)
ARM: dts: exynops4210: really add universal_c210 dts
ARM: dts: exynos4210: Add basic dts file for universal_c210 board
ARM: dts: exynos4: Add node for PWM device
ARM: SAMSUNG: Do not register legacy timer interrupts on Exynos
clocksource: samsung_pwm_timer: Work around rounding errors in clockevents core
clocksource: samsung_pwm_timer: Correct programming of clock events
clocksource: samsung_pwm_timer: Use proper clockevents max_delta
clocksource: samsung_pwm_timer: Add support for non-DT platforms
clocksource: samsung_pwm_timer: Drop unused samsung_pwm struct
clocksource: samsung_pwm_timer: Keep all driver data in a structure
clocksource: samsung_pwm_timer: Make PWM spinlock global
clocksource: samsung_pwm_timer: Let platforms select the driver
Documentation: Add device tree bindings for Samsung PWM timers
clocksource: add samsung pwm timer driver
irqchip: exynos: look up irq using irq_find_mapping
irqchip: exynos: pass irq_base from platform
irqchip: exynos: localize irq lookup for ATAGS
irqchip: exynos: allocate combiner_data dynamically
irqchip: exynos: pass max combiner number to combiner_init
ARM: exynos: add missing properties for combiner IRQs
...
Pull ARM SoC late cleanups from Arnd Bergmann:
"These are cleanups and smaller changes that either depend on earlier
feature branches or came in late during the development cycle. We
normally try to get all cleanups early, so these are the exceptions:
- A follow-up on the clocksource reworks, hopefully the last time we
need to merge clocksource subsystem changes through arm-soc.
A first set of patches was part of the original 3.10 arm-soc
cleanup series because of interdependencies with timer drivers now
moved out of arch/arm.
- Migrating the SPEAr13xx platform away from using auxdata for DMA
channel descriptions towards using information in device tree,
based on the earlier SPEAr multiplatform series
- A few follow-ups on the Atmel SAMA5 support and other changes for
Atmel at91 based on the larger at91 reworks.
- Moving the armada irqchip implementation to drivers/irqchip
- Several OMAP cleanups following up on the larger series already
merged in 3.10."
* tag 'cleanup-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (50 commits)
ARM: OMAP4: change the device names in usb_bind_phy
ARM: OMAP2+: Fix mismerge for timer.c between ff931c82 and da4a686a
ARM: SPEAr: conditionalize SMP code
ARM: arch_timer: Silence debug preempt warnings
ARM: OMAP: remove unused variable
serial: amba-pl011: fix !CONFIG_DMA_ENGINE case
ata: arasan: remove the need for platform_data
ARM: at91/sama5d34ek.dts: remove not needed compatibility string
ARM: at91: dts: add MCI DMA support
ARM: at91: dts: add i2c dma support
ARM: at91: dts: set #dma-cells to the correct value
ARM: at91: suspend both memory controllers on at91sam9263
irqchip: armada-370-xp: slightly cleanup irq controller driver
irqchip: armada-370-xp: move IRQ handler to avoid forward declaration
irqchip: move IRQ driver for Armada 370/XP
ARM: mvebu: move L2 cache initialization in init_early()
devtree: add binding documentation for sp804
ARM: integrator-cp: convert use CLKSRC_OF for timer init
ARM: versatile: use OF init for sp804 timer
ARM: versatile: add versatile dtbs to dtbs target
...
Pull ARM SoC device tree updates (part 2) from Arnd Bergmann:
"These are mostly new device tree bindings for existing drivers, as
well as changes to the device tree source files to add support for
those devices, and a couple of new boards, most notably Samsung's
Exynos5 based Chromebook.
The changes depend on earlier platform specific updates and touch the
usual platforms: omap, exynos, tegra, mxs, mvebu and davinci."
* tag 'dt-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (169 commits)
ARM: exynos: dts: cros5250: add EC device
ARM: dts: Add sbs-battery for exynos5250-snow
ARM: dts: Add i2c-arbitrator bus for exynos5250-snow
ARM: dts: add mshc controller node for Exynos4x12 SoCs
ARM: dts: Add chip-id controller node on Exynos4/5 SoC
ARM: EXYNOS: Create virtual I/O mapping for Chip-ID controller using device tree
ARM: davinci: da850-evm: add SPI flash support
ARM: davinci: da850: override SPI DT node device name
ARM: davinci: da850: add SPI1 DT node
spi/davinci: add DT binding documentation
spi/davinci: no wildcards in DT compatible property
ARM: dts: mvebu: Convert mvebu device tree files to 64 bits
ARM: dts: mvebu: introduce internal-regs node
ARM: dts: mvebu: Convert all the mvebu files to use the range property
ARM: dts: mvebu: move all peripherals inside soc
ARM: dts: mvebu: fix cpus section indentation
ARM: davinci: da850: add EHRPWM & ECAP DT node
ARM/dts: OMAP3: fix pinctrl-single configuration
ARM: dts: Add OMAP3430 SDP NOR flash memory binding
ARM: dts: Add NOR flash bindings for OMAP2420 H4
...
Pull ARM SoC platform updates (part 3) from Arnd Bergmann:
"This is the third and smallest of the SoC specific updates. Changes
include:
- SMP support for the Xilinx zynq platform
- Smaller imx changes
- LPAE support for mvebu
- Moving the orion5x, kirkwood, dove and mvebu platforms to a common
"mbus" driver for their internal devices.
It would be good to get feedback on the location of the "mbus" driver.
Since this is used on multiple platforms may potentially get shared
with other architectures (powerpc and arm64), it was moved to
drivers/bus/. We expect other similar drivers to get moved to the
same place in order to avoid creating more top-level directories under
drivers/ or cluttering up the messy drivers/misc/ even more."
* tag 'soc-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (50 commits)
ARM: imx: reset_controller may be disabled
ARM: mvebu: Align the internal registers virtual base to support LPAE
ARM: mvebu: Limit the DMA zone when LPAE is selected
arm: plat-orion: remove addr-map code
arm: mach-mv78xx0: convert to use the mvebu-mbus driver
arm: mach-orion5x: convert to use mvebu-mbus driver
arm: mach-dove: convert to use mvebu-mbus driver
arm: mach-kirkwood: convert to use mvebu-mbus driver
arm: mach-mvebu: convert to use mvebu-mbus driver
ARM i.MX53: set CLK_SET_RATE_PARENT flag on the tve_ext_sel clock
ARM i.MX53: tve_di clock is not part of the CCM, but of TVE
ARM i.MX53: make tve_ext_sel propagate rate change to PLL
ARM i.MX53: Remove unused tve_gate clkdev entry
ARM i.MX5: Remove tve_sel clock from i.MX53 clock tree
ARM: i.MX5: Add PATA and SRTC clocks
ARM: imx: do not bring up unavailable cores
ARM: imx: add initial imx6dl support
ARM: imx1: mm: add call to mxc_device_init
ARM: imx_v4_v5_defconfig: Add CONFIG_GPIO_SYSFS
ARM: imx_v6_v7_defconfig: Select CONFIG_PERF_EVENTS
...
Pull ARM SoC platform updates (part 2) from Arnd Bergmann:
"These patches are all for Renesas shmobile, and depend on the earlier
pinctrl updates. Remarkably, this adds support for three new SoCs:
r8a73a4, r8a73a4 and r8a7778. The bulk of the code added for these is
for pinctrl (using the new subsystem) and for clocks (not yet using
the common clock subsystem). The latter will have to get converted in
one of the upcoming releases, but shmobile is not ready for that yet.
The series also contains Renesas shmobile board changes, adding one
board file for each of the three new SoCs. These boards are using a
mix of classic and device-tree based probing, as there is still a lot
of infrastructure in shmobile that has not been converted to DT yet.
Once those are resolved to the degree that no board specific setup
code is needed, they can get folded into the respective SoC setup files."
* tag 'soc-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (78 commits)
ARM: shmobile: use r8a7790 timer setup code on Lager
ARM: shmobile: force enable of r8a7790 arch timer
ARM: shmobile: Add second I/O range for r8a7790 PFC
ARM: shmobile: bockw: enable network settings on bootargs
ARM: shmobile: bockw: add SMSC ethernet support
ARM: shmobile: R8A7778: add Ether support
ARM: shmobile: bockw: enable SMSC ethernet on defconfig
ARM: shmobile: r8a7778: add r8a7778_init_irq_extpin()
ARM: shmobile: r8a7778: remove pointless PLATFORM_INFO()
ARM: shmobile: mackerel: clean up MMCIF vs. SDHI1 selection
ARM: shmobile: mackerel: add interrupt names for SDHI0
ARM: shmobile: mackerel: switch SDHI and MMCIF interfaces to slot-gpio
ARM: shmobile: mackerel: remove OCR masks, where regulators are used
ARM: shmobile: mackerel: SDHI resources do not have to be numbered
ARM: shmobile: Initial r8a7790 Lager board support
ARM: shmobile: APE6EVM LAN9220 support
ARM: shmobile: APE6EVM PFC support
ARM: shmobile: APE6EVM base support
ARM: shmobile: kzm9g-reference: add ethernet support
ARM: shmobile: add R-Car M1A Bock-W platform support
...
Jeff is leaving for something more interesting and I'm inheriting the
maintainership of libata. Thanks a lot for the good work and have
fun, Jeff!
v2: The original path forgot to update git tree URL. Updated.
Spotted by Sergei.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Pull more vhost fixes from Michael Tsirkin:
"This fixes some minor issues in the patches that have been merged.
We also finally drop the workaround disabling event_idx for scsi: it
was always questionable, and now we know it's not needed.
There's also a memory leak fix"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
vhost-scsi: Enable VIRTIO_RING_F_EVENT_IDX
vhost: drop virtio_net.h dependency
vhost-net: Cleanup vhost_ubuf and vhost_zcopy
vhost: Remove vhost_enable_zcopy in vhost.h
vhost: Remove comments for hdr in vhost.h
vhost: Move VHOST_NET_FEATURES to net.c
vhost-net: Free ubuf when vhost_dev_set_owner fails
vhost: Export vhost_dev_set_owner
Pull fuse updates from Miklos Szeredi:
"This contains two patchsets from Maxim Patlasov.
The first reworks the request throttling so that only async requests
are throttled. Wakeup of waiting async requests is also optimized.
The second series adds support for async processing of direct IO which
optimizes direct IO and enables the use of the AIO userspace
interface."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: add flag to turn on async direct IO
fuse: truncate file if async dio failed
fuse: optimize short direct reads
fuse: enable asynchronous processing direct IO
fuse: make fuse_direct_io() aware about AIO
fuse: add support of async IO
fuse: move fuse_release_user_pages() up
fuse: optimize wake_up
fuse: implement exclusive wakeup for blocked_waitq
fuse: skip blocking on allocations of synchronous requests
fuse: add flag fc->initialized
fuse: make request allocations for background processing explicit
Pull powerpc updates from Benjamin Herrenschmidt:
"Here are a few more powerpc bits that I would like in 3.10.
Mostly remaining bolts & screw tightening of power8 support such as
actually exposing the new features via the previously added AT_HWCAP2,
and a few fixes, some of them for problems exposed recently like
irqdomain warnings or sysfs access permission issues, some exposed by
power8 hardware.
The only change outside of arch/powerpc is a small one to irqdomain.c
to allow silent failure to fix a problem on Cell where we get a dozen
WARN_ON's tripping at boot for what is basically a normal case."
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Make hard_irq_disable() do the right thing vs. irq tracing
powerpc/topology: Fix spurr attribute permission
powerpc/pci: Support per-aperture memory offset
powerpc/cell/iommu: Improve error message for missing node
powerpc/cell/spufs: Fix status attribute permission
irqdomain: Allow quiet failure mode
powerpc/pnv: Fix "compatible" property for P8 PHB
powerpc/pci: Don't add bogus empty resources to PHBs
powerpc/powerpnv: Properly handle failure starting CPUs
powerpc/cputable: Advertise support for ISEL/HTM/DSCR/TAR on POWER8
powerpc/cputable: Advertise ISEL support on appropriate embedded processors
powerpc/cputable: Advertise DSCR support on P7/P7+
powerpc/cputable: Reserve bits in HWCAP2 for new features
powerpc/pseries: Perform proper max_bus_speed detection
powerpc/pseries: Force 32 bit MSIs for devices that require it
powerpc/tm: Fix null pointer deference in flush_hash_page
powerpc/powernv: Defer OPAL exception handler registration
powerpc: Emulate non privileged DSCR read and write
Merge rwsem optimizations from Michel Lespinasse:
"These patches extend Alex Shi's work (which added write lock stealing
on the rwsem slow path) in order to provide rwsem write lock stealing
on the fast path (that is, without taking the rwsem's wait_lock).
I have unfortunately been unable to push this through -next before due
to Ingo Molnar / David Howells / Peter Zijlstra being busy with other
things. However, this has gotten some attention from Rik van Riel and
Davidlohr Bueso who both commented that they felt this was ready for
v3.10, and Ingo Molnar has said that he was OK with me pushing
directly to you. So, here goes :)
Davidlohr got the following test results from pgbench running on a
quad-core laptop:
| db_size | clients | tps-vanilla | tps-rwsem |
+---------+----------+----------------+--------------+
| 160 MB | 1 | 5803 | 6906 | + 19.0%
| 160 MB | 2 | 13092 | 15931 |
| 160 MB | 4 | 29412 | 33021 |
| 160 MB | 8 | 32448 | 34626 |
| 160 MB | 16 | 32758 | 33098 |
| 160 MB | 20 | 26940 | 31343 | + 16.3%
| 160 MB | 30 | 25147 | 28961 |
| 160 MB | 40 | 25484 | 26902 |
| 160 MB | 50 | 24528 | 25760 |
------------------------------------------------------
| 1.6 GB | 1 | 5733 | 7729 | + 34.8%
| 1.6 GB | 2 | 9411 | 19009 | + 101.9%
| 1.6 GB | 4 | 31818 | 33185 |
| 1.6 GB | 8 | 33700 | 34550 |
| 1.6 GB | 16 | 32751 | 33079 |
| 1.6 GB | 20 | 30919 | 31494 |
| 1.6 GB | 30 | 28540 | 28535 |
| 1.6 GB | 40 | 26380 | 27054 |
| 1.6 GB | 50 | 25241 | 25591 |
------------------------------------------------------
| 7.6 GB | 1 | 5779 | 6224 |
| 7.6 GB | 2 | 10897 | 13611 | + 24.9%
| 7.6 GB | 4 | 32683 | 33108 |
| 7.6 GB | 8 | 33968 | 34712 |
| 7.6 GB | 16 | 32287 | 32895 |
| 7.6 GB | 20 | 27770 | 31689 | + 14.1%
| 7.6 GB | 30 | 26739 | 29003 |
| 7.6 GB | 40 | 24901 | 26683 |
| 7.6 GB | 50 | 17115 | 25925 | + 51.5%
------------------------------------------------------
(Davidlohr also has one additional patch which further improves
throughput, though I will ask him to send it directly to you as I have
suggested some minor changes)."
* emailed patches from Michel Lespinasse <walken@google.com>:
rwsem: no need for explicit signed longs
x86 rwsem: avoid taking slow path when stealing write lock
rwsem: do not block readers at head of queue if other readers are active
rwsem: implement support for write lock stealing on the fastpath
rwsem: simplify __rwsem_do_wake
rwsem: skip initial trylock in rwsem_down_write_failed
rwsem: avoid taking wait_lock in rwsem_down_write_failed
rwsem: use cmpxchg for trying to steal write lock
rwsem: more agressive lock stealing in rwsem_down_write_failed
rwsem: simplify rwsem_down_write_failed
rwsem: simplify rwsem_down_read_failed
rwsem: move rwsem_down_failed_common code into rwsem_down_{read,write}_failed
rwsem: shorter spinlocked section in rwsem_down_failed_common()
rwsem: make the waiter type an enumeration rather than a bitmask
Pull slab changes from Pekka Enberg:
"The bulk of the changes are more slab unification from Christoph.
There's also few fixes from Aaron, Glauber, and Joonsoo thrown into
the mix."
* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (24 commits)
mm, slab_common: Fix bootstrap creation of kmalloc caches
slab: Return NULL for oversized allocations
mm: slab: Verify the nodeid passed to ____cache_alloc_node
slub: tid must be retrieved from the percpu area of the current processor
slub: Do not dereference NULL pointer in node_match
slub: add 'likely' macro to inc_slabs_node()
slub: correct to calculate num of acquired objects in get_partial_node()
slub: correctly bootstrap boot caches
mm/sl[au]b: correct allocation type check in kmalloc_slab()
slab: Fixup CONFIG_PAGE_ALLOC/DEBUG_SLAB_LEAK sections
slab: Handle ARCH_DMA_MINALIGN correctly
slab: Common definition for kmem_cache_node
slab: Rename list3/l3 to node
slab: Common Kmalloc cache determination
stat: Use size_t for sizes instead of unsigned
slab: Common function to create the kmalloc array
slab: Common definition for the array of kmalloc caches
slab: Common constants for kmalloc boundaries
slab: Rename nodelists to node
slab: Common name for the per node structures
...
Pull misc kbuild updates from Michal Marek:
"Non-critical kbuild changes:
- make coccicheck improvements, but no new semantic patches this time
- make rpm improvements
- make tar-pkg change to include the architecture in the filename.
This is a deliberate incompatibility, but nobody has complained so
far and it is useful if you build for different architectures. It
also matches what the deb-pkg and rpm-pkg targets produce.
- kbuild documentation fix"
* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
rpm-pkg: Remove pointless set -e statements
rpm-pkg: Always regenerate the specfile
rpm-pkg: Do not write to the parent directory
rpm-pkg: Do not package the whole source directory
buildtar: Add ARCH to the archive name
Coccinelle: Fix patch output when coccicheck is used with M= and C=
Coccinelle: Add support to the SPFLAGS variable
Coccinelle: Cleanup the setting of the FLAGS and OPTIONS variables
Coccinelle: Restore coccicheck verbosity in ONLINE mode (C=1 or C=2)
scripts/package/Makefile: compare objtree with srctree instead of test KBUILD_OUTPUT
doc: change example to existing Makefile fragment
scripts/tags.sh: Add magic for OFFSET and DEFINE
Pull kconfig updates from Michal Marek:
- use pkg-config to detect curses libraries
- clean up the way curses headers are searched
- Some randconfig fixes, of which one had to be reverted
- KCONFIG_SEED for randconfig debugging
- memuconfig memory leak plugged
- menuconfig > breadcrumbs > navigation
- xconfig compilation fix
- Other minor fixes
* 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kconfig: fix lists definition for C++
Revert "kconfig: fix randomising choice entries in presence of KCONFIG_ALLCONFIG"
kconfig: implement KCONFIG_PROBABILITY for randconfig
kconfig: allow specifying the seed for randconfig
kconfig: fix randomising choice entries in presence of KCONFIG_ALLCONFIG
kconfig: do not override symbols already set
kconfig: fix randconfig tristate detection
kconfig/lxdialog: rationalise the include paths where to find {.n}curses{,w}.h
menuconfig: Add "breadcrumbs" navigation aid
menuconfig: Fix memory leak introduced by jump keys feature
merge_config.sh: Avoid creating unnessary source softlinks
kconfig: optionally use pkg-config to detect ncurses libs
menuconfig: optionally use pkg-config to detect ncurses libs
Pull kbuild changes from Michal Marek:
"Kbuild commits for v3.10-rc1:
- Fix make mrproper after mod/file2alias rework
- Fix ld-option Makefile function
- Rewrite headers_install to shell to drop Perl dependency.
There are some more patches I have to look at, so I might send another
pull request later. Or just queue them for 3.11."
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
Fix cleaning in scripts/mod
headers_install.pl: convert to headers_install.sh
kbuild: fix ld-option function
Searching for PPC_EFIKA results in a segmentation fault, and it's
because get_symbol_prop() returns NULL.
In this case CONFIG_PPC_EFIKA is defined in arch/powerpc/platforms/
52xx/Kconfig, so it won't be parsed if ARCH!=PPC, but menuconfig knows
this symbol when it parses sound/soc/fsl/Kconfig:
config SND_MPC52xx_SOC_EFIKA
tristate "SoC AC97 Audio support for bbplan Efika and STAC9766"
depends on PPC_EFIKA
This bug was introduced by commit bcdedcc1af ("menuconfig: print more
info for symbol without prompts").
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Tested-by: Libo Chen <libo.chen@huawei.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
modify __down_write[_nested] and __down_write_trylock to grab the write
lock whenever the active count is 0, even if there are queued waiters
(they must be writers pending wakeup, since the active count is 0).
Note that this is an optimization only; architectures without this
optimization will still work fine:
- __down_write() would take the slow path which would take the wait_lock
and then try stealing the lock (as in the spinlocked rwsem implementation)
- __down_write_trylock() would fail, but callers must be ready to deal
with that - since there are some writers pending wakeup, they could
have raced with us and obtained the lock before we steal it.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change fixes a race condition where a reader might determine it
needs to block, but by the time it acquires the wait_lock the rwsem has
active readers and no queued waiters.
In this situation the reader can run in parallel with the existing
active readers; it does not need to block until the active readers
complete.
Thanks to Peter Hurley for noticing this possible race.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we decide to wake up readers, we must first grant them as many read
locks as necessary, and then actually wake up all these readers. But in
order to know how many read shares to grant, we must first count the
readers at the head of the queue. This might take a while if there are
many readers, and we want to be protected against a writer stealing the
lock while we're counting. To that end, we grant the first reader lock
before counting how many more readers are queued.
We also require some adjustments to the wake_type semantics.
RWSEM_WAKE_NO_ACTIVE used to mean that we had found the count to be
RWSEM_WAITING_BIAS, in which case the rwsem was known to be free as
nobody could steal it while we hold the wait_lock. This doesn't make
sense once we implement fastpath write lock stealing, so we now use
RWSEM_WAKE_ANY in that case.
Similarly, when rwsem_down_write_failed found that a read lock was
active, it would use RWSEM_WAKE_READ_OWNED which signalled that new
readers could be woken without checking first that the rwsem was
available. We can't do that anymore since the existing readers might
release their read locks, and a writer could steal the lock before we
wake up additional readers. So, we have to use a new RWSEM_WAKE_READERS
value to indicate we only want to wake readers, but we don't currently
hold any read lock.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is mostly for cleanup value:
- We don't need several gotos to handle the case where the first
waiter is a writer. Two simple tests will do (and generate very
similar code).
- In the remainder of the function, we know the first waiter is a reader,
so we don't have to double check that. We can use do..while loops
to iterate over the readers to wake (generates slightly better code).
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In rwsem_down_write_failed(), if there are active locks after we wake up
(i.e. the lock got stolen from us), skip taking the wait_lock and go
back to sleep immediately.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using rwsem_atomic_update to try stealing the write lock forced us to
undo the adjustment in the failure path. We can have simpler and faster
code by using cmpxchg instead.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some small code simplifications can be achieved by doing more agressive
lock stealing:
- When rwsem_down_write_failed() notices that there are no active locks
(and thus no thread to wake us if we decided to sleep), it used to wake
the first queued process. However, stealing the lock is also sufficient
to deal with this case, so we don't need this check anymore.
- In try_get_writer_sem(), we can steal the lock even when the first waiter
is a reader. This is correct because the code path that wakes readers is
protected by the wait_lock. As to the performance effects of this change,
they are expected to be minimal: readers are still granted the lock
(rather than having to acquire it themselves) when they reach the front
of the wait queue, so we have essentially the same behavior as in
rwsem-spinlock.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When waking writers, we never grant them the lock - instead, they have
to acquire it themselves when they run, and remove themselves from the
wait_list when they succeed.
As a result, we can do a few simplifications in rwsem_down_write_failed():
- We don't need to check for !waiter.task since __rwsem_do_wake() doesn't
remove writers from the wait_list
- There is no point releaseing the wait_lock before entering the wait loop,
as we will need to reacquire it immediately. We can change the loop so
that the lock is always held at the start of each loop iteration.
- We don't need to get a reference on the task structure, since the task
is responsible for removing itself from the wait_list. There is no risk,
like in the rwsem_down_read_failed() case, that a task would wake up and
exit (thus destroying its task structure) while __rwsem_do_wake() is
still running - wait_lock protects against that.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When trying to acquire a read lock, the RWSEM_ACTIVE_READ_BIAS
adjustment doesn't cause other readers to block, so we never have to
worry about waking them back after canceling this adjustment in
rwsem_down_read_failed().
We also never want to steal the lock in rwsem_down_read_failed(), so we
don't have to grab the wait_lock either.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the rwsem_down_failed_common function and replace it with two
identical copies of its code in rwsem_down_{read,write}_failed.
This is because we want to make different optimizations in
rwsem_down_{read,write}_failed; we are adding this pure-duplication
step as a separate commit in order to make it easier to check the
following steps.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change reduces the size of the spinlocked and TASK_UNINTERRUPTIBLE
sections in rwsem_down_failed_common():
- We only need the sem->wait_lock to insert ourselves on the wait_list;
the waiter node can be prepared outside of the wait_lock.
- The task state only needs to be set to TASK_UNINTERRUPTIBLE immediately
before checking if we actually need to sleep; it doesn't need to protect
the entire function.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are not planning to add some new waiter flags, so we can convert the
waiter type into an enumeration.
Background: David Howells suggested I do this back when I tried adding
a new waiter type for unfair readers. However, I believe the cleanup
applies regardless of that use case.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
From Tony Lindgren <tony@atomide.com>:
An urgent fix for a timer mismerge for and a regression fix for
musb device naming change.
* tag 'omap-for-v3.10/fixes-for-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: OMAP4: change the device names in usb_bind_phy
ARM: OMAP2+: Fix mismerge for timer.c between ff931c82 and da4a686a
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
It was disabled as a workaround. Now userspace bits work fine with it.
The broken version was not ever committed to QEMU, I guess the same is
true for nlkt.
So, let's enable it.
Signed-off-by: Asias He <asias@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
If hard_irq_disable() is called while interrupts are already soft-disabled
(which is the most common case) all is already well.
However you can (and in some cases want) to call it while everything is
enabled (to make sure you don't get a lazy even, for example before entry
into KVM guests) and in this case we need to inform the irq tracer that
the irqs are going off.
We have to change the inline into a macro to avoid an include circular
dependency hell hole.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
same story as with the previous patches - note that return
value of blkdev_close() is lost, since there's nowhere the
caller (__fput()) could return it to.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
After the device names are created using PLATFORM_DEVID_AUTO, the old
device names given in usb_bind_phy are no longer valid causing the musb
controller not to get the phy reference. Updated the usb_bind_phy with
the new device names to get MUSB functional in omap4 panda.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Looks like the timer.c fixes in commit ff931c82 (ARM: OMAP: clocks:
Delay clk inits atleast until slab is initialized) got lost in a
merge with da4a686a (ARM: smp_twd: convert to use CLKSRC_OF init).
Without the omap_clk_init() calls none of OMAP family of devices
boot.
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
[tony@atomide.com: updated comments to describe merge error]
Signed-off-by: Tony Lindgren <tony@atomide.com>
Pull networking fixes from David Miller:
"Just a small pile of fixes"
1) Fix race conditions in IP fragmentation LRU list handling, from
Konstantin Khlebnikov.
2) vfree() is no longer verboten in interrupts, so deferring is
pointless, from Al Viro.
3) Conversion from mutex to semaphore in netpoll left trylock test
inverted, caught by Dan Carpenter.
4) 3c59x uses wrong base address when releasing regions, from Sergei
Shtylyov.
5) Bounds checking in TIPC from Dan Carpenter.
6) Fastopen cookies should not be expired as aggressively as other TCP
metrics. From Eric Dumazet.
7) Fix retrieval of MAC address in ibmveth, from Ben Herrenschmidt.
8) Don't use "u16" in virtio user headers, from Stephen Hemminger
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
tipc: potential divide by zero in tipc_link_recv_fragment()
tipc: add a bounds check in link_recv_changeover_msg()
net/usb: new driver for RTL8152
3c59x: fix freeing nonexistent resource on driver unload
netpoll: inverted down_trylock() test
rps_dev_flow_table_release(): no need to delay vfree()
fib_trie: no need to delay vfree()
net: frag, fix race conditions in LRU list maintenance
tcp: do not expire TCP fastopen cookies
net/eth/ibmveth: Fixup retrieval of MAC address
virtio: don't expose u16 in userspace api
Pull LED subsystem updates from Bryan Wu:
- move LED trigger drivers into a new directory
- lp55xx common driver updates
- other led drivers updates and bug fixing
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds:
leds: leds-asic3: switch to using SIMPLE_DEV_PM_OPS
leds: leds-bd2802: add CONFIG_PM_SLEEP to suspend/resume functions
leds: lp55xx: configure the clock detection
leds: lp55xx: use common clock framework when external clock is used
leds: leds-ns2: fix oops at module removal
leds: leds-pwm: Defer led_pwm_set() if PWM can sleep
leds: lp55xx: fix the sysfs read operation
leds: lm355x, lm3642: support camera LED triggers for flash and torch
leds: add camera LED triggers
leds: trigger: use inline functions instead of macros
leds: tca6507: Use of_match_ptr() macro
leds: wm8350: Complain if we fail to reenable DCDC
leds: renesas: set gpio_request_one() flags param correctly
leds: leds-ns2: set devm_gpio_request_one() flags param correctly
leds: leds-lt3593: set devm_gpio_request_one() flags param correctly
leds: leds-bd2802: remove erroneous __exit annotation
leds: atmel-pwm: remove erroneous __exit annotation
leds: move LED trigger drivers into new subdirectory
leds: add new LP5562 LED driver
Pull GPIO changes from Grant Likely:
"The usual selection of bug fixes and driver updates for GPIO. Nothing
really stands out except the addition of the GRGPIO driver and some
enhacements to ACPI support"
I'm pulling this despite the earlier mess. Let's hope it compiles these
days.
* tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux: (46 commits)
gpio: grgpio: Add irq support
gpio: grgpio: Add device driver for GRGPIO cores
gpiolib-acpi: introduce acpi_get_gpio_by_index() helper
GPIO: gpio-generic: remove kfree() from bgpio_remove call
gpio / ACPI: Handle ACPI events in accordance with the spec
gpio: lpc32xx: Fix off-by-one valid range checking for bank
gpio: mcp23s08: convert driver to DT
gpio/omap: force restore if context loss is not detectable
gpio/omap: optimise interrupt service routine
gpio/omap: remove extra context restores in *_runtime_resume()
gpio/omap: free irq domain in probe() failure paths
gpio: gpio-generic: Add 16 and 32 bit big endian byte order support
gpio: samsung: Add terminating entry for exynos_pinctrl_ids
gpio: mvebu: add dbg_show function
MAX7301 GPIO: Do not force SPI speed when using OF Platform
gpio: gpio-tps65910.c: fix checkpatch error
gpio: gpio-timberdale.c: fix checkpatch error
gpio: gpio-tc3589x.c: fix checkpatch errors
gpio: gpio-stp-xway.c: fix checkpatch error
gpio: gpio-sch.c: fix checkpatch error
...
Pull pwm changes from Thierry Reding:
"Nothing very exciting this time around. A couple of bug fixes and a
lot of cleanup across the board. The DaVinci 8xx family of SoCs now
use the same driver as the AM33xx family.
Many thanks to Axel Lin and Jingoo Han who have done a great job
fixing various bugs and inconsistencies."
* tag 'for-3.10-rc1' of git://gitorious.org/linux-pwm/linux-pwm: (27 commits)
pwm: lpc32xx: Don't change PWM_ENABLE bit in lpc32xx_pwm_config
pwm: lpc32xx: Properly set PWM_ENABLE bit in lpc32xx_pwm_[enable|disable]
pwm: Constify OF match tables
pwm: pwm-tiehrpwm: Update device-tree binding document
pwm: pwm-tiecap: Update device-tree binding document
pwm: puv3: Remove unused enabled filed from struct puv3_pwm_chip
pwm: pxa: Remove PWM_ID_BASE macro
pwm: spear: Remove unused *dev from struct spear_pwm_chip
pwm: mxs: Remove unused *dev from struct mxs_pwm_chip
pwm: twl: Return proper error if twl6030_pwm_enable() fails
pwm: pxa: Remove clk_enabled field from struct pxa_pwm_chip
pwm: imx: Remove enabled field from struct imx_chip
pwm: twl: Add .owner to struct pwm_ops
pwm: twl-led: Add .owner to struct pwm_ops
pwm: atmel-tcb: Add .owner to struct pwm_ops
pwm: ab8500: Add .owner to struct pwm_ops
pwm: spear: Fix checking return value of clk_enable() and clk_prepare()
pwm: tiehrpwm: Staticize non-exported symbols
pwm: tiecap: Staticize non-exported symbols
pwm: ab8500: Fix trivial typo in dev_err message
...
Pull IOMMU updates from Joerg Roedel:
"The updates are mostly about the x86 IOMMUs this time.
Exceptions are the groundwork for the PAMU IOMMU from Freescale (for a
PPC platform) and an extension to the IOMMU group interface.
On the x86 side this includes a workaround for VT-d to disable
interrupt remapping on broken chipsets. On the AMD-Vi side the most
important new feature is a kernel command-line interface to override
broken information in IVRS ACPI tables and get interrupt remapping
working this way.
Besides that there are small fixes all over the place."
* tag 'iommu-updates-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (24 commits)
iommu/tegra: Fix printk formats for dma_addr_t
iommu: Add a function to find an iommu group by id
iommu/vt-d: Remove warning for HPET scope type
iommu: Move swap_pci_ref function to drivers/iommu/pci.h.
iommu/vt-d: Disable translation if already enabled
iommu/amd: fix error return code in early_amd_iommu_init()
iommu/AMD: Per-thread IOMMU Interrupt Handling
iommu: Include linux/err.h
iommu/amd: Workaround for ERBT1312
iommu/amd: Document ivrs_ioapic and ivrs_hpet parameters
iommu/amd: Don't report firmware bugs with cmd-line ivrs overrides
iommu/amd: Add ioapic and hpet ivrs override
iommu/amd: Add early maps for ioapic and hpet
iommu/amd: Extend IVRS special device data structure
iommu/amd: Move add_special_device() to __init
iommu: Fix compile warnings with forward declarations
iommu/amd: Properly initialize irq-table lock
iommu/amd: Use AMD specific data structure for irq remapping
iommu/amd: Remove map_sg_no_iommu()
iommu/vt-d: add quirk for broken interrupt remapping on 55XX chipsets
...
This series from Tomasz Figa restores support for the pwm clocksource
in Exynos, which was broken during the conversion of the platform
to the common clk framework. The clocksource is only used in one
board in the mainline kernel (universal_c210), and this makes it
work for DT based probing as well as restoring the non-DT based
case.
* exynos/pwm-clocksource:
ARM: dts: exynops4210: really add universal_c210 dts
ARM: dts: exynos4210: Add basic dts file for universal_c210 board
ARM: dts: exynos4: Add node for PWM device
ARM: SAMSUNG: Do not register legacy timer interrupts on Exynos
clocksource: samsung_pwm_timer: Work around rounding errors in clockevents core
clocksource: samsung_pwm_timer: Correct programming of clock events
clocksource: samsung_pwm_timer: Use proper clockevents max_delta
clocksource: samsung_pwm_timer: Add support for non-DT platforms
clocksource: samsung_pwm_timer: Drop unused samsung_pwm struct
clocksource: samsung_pwm_timer: Keep all driver data in a structure
clocksource: samsung_pwm_timer: Make PWM spinlock global
clocksource: samsung_pwm_timer: Let platforms select the driver
Documentation: Add device tree bindings for Samsung PWM timers
clocksource: add samsung pwm timer driver
Conflicts:
arch/arm/boot/dts/Makefile
arch/arm/mach-exynos/common.c
drivers/clocksource/Kconfig
drivers/clocksource/Makefile
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
There is no reason to keep the clksrc cleanups separate from the
other cleanups, and this resolves some merge conflicts.
Conflicts:
arch/arm/mach-spear/spear13xx.c
drivers/irqchip/Makefile
Make sure devicetable-offsets.h is cleaned in the scripts/mod directory
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This is support for the ARM Chromebook, originally scheduled
as a "late" pull request. Since it's already late now, we
can combine this into the existing next/dt2 branch.
* late/dt:
ARM: exynos: dts: cros5250: add EC device
ARM: dts: Add sbs-battery for exynos5250-snow
ARM: dts: Add i2c-arbitrator bus for exynos5250-snow
ARM: dts: Add chip-id controller node on Exynos4/5 SoC
ARM: EXYNOS: Create virtual I/O mapping for Chip-ID controller using device tree
