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Commit d941f86fad41b ("ARM: l2c: AM43x: add L2 cache support") enabled
the L2 cache support for the am43xx SoC, but caused a build regression
when the driver for that cache controller is disabled:
arch/arm/mach-omap2/built-in.o: In function `am43xx_init_early':
:(.init.text+0xb20): undefined reference to `omap_l2_cache_init'
This did not happen for OMAP4, which has the same call, but enables
the l2x0 driver unconditionally. We could do the same thing for
am43xx, but it seems better to allow turning it off and make the
code work in either case.
This adds an inline wrapper for omap_l2_cache_init for the disabled
case, and removes the 'select' from OMAP4 so it becomes a user
visible option.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: linux-omap@vger.kernel.org
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Merge a stable base (Linux 3.16-rc1)
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Fixes possible issue in case pdev name contains formatting characters.
Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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simple_strto*() are obsolete; use kstrto*() instead. Add proper error
checking.
Signed-off-by: Christoph Jaeger <christophjaeger@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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This patch fixes checkpatch warnings:
"WARNING: __packed is preferred over __attribute__((packed))"
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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On Acer Aspire V5-573G battery notifications are sometimes
triggered too early. For example, when AC is unplugged and
notification is triggered, battery state is still reported as
"Full", and changes to "Discharging" only after short delay,
without any notification.
This patch solves the problem by adding 1 second sleep.
Similar quirk is already implemented in AC driver for other laptop.
Signed-off-by: Alexander Mezin <mezin.alexander@gmail.com>
Acked-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Use callback for setting up quirk instead of checking return code
of dmi_check_system(). This change will allow using bat_dmi_table
for other quirks.
Signed-off-by: Alexander Mezin <mezin.alexander@gmail.com>
Acked-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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On Intel Baytrail, some I2C host controllers are held in reset when the OS
gets control. This causes the driver to fail to detect the hardware
properly.
Fix this so that we make sure that the I2C host controller is not in reset
when the driver gets probe'd.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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into drm-next
two fixes for the deep color support in radeon.
* 'drm-next-3.16' of git://people.freedesktop.org/~agd5f/linux:
drm/radeon: Bypass hw lut's for > 8 bpc framebuffer scanout.
drm/radeon: use pixel formats instead of depth/bpp
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git://anongit.freedesktop.org/git/nouveau/linux-2.6 into drm-next
This is bigger because it regenerates the internal firmwares after a fix.
* 'drm-nouveau-next' of git://anongit.freedesktop.org/git/nouveau/linux-2.6:
drm/nouveau/doc: update the thermal documentation
drm/nouveau/pwr: fix typo in fifo wrap handling
drm/nv50/disp: fix a potential oops in supervisor handling
drm/nouveau/disp/dp: don't touch link config after success
drm/nouveau/kms: reference vblank for crtc during pageflip.
drm/gk104/fb/ram: fixups from an earlier search+replace
drm/nv50/gr: remove an unneeded write while initialising PGRAPH
drm/nv50/gr: fix overlap while zeroing zcull regions
drm/gf100-/gr: report class data to host on fwmthd failure
drm/gk104/ibus: increase various random timeouts
drm/gk104/clk: only touch divider for mode we'll be using
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Changes:
- Change the maintainer's address (the labri address will expire soon);
- Drop the note about not all families supporting all fan modes;
- Add a note about the reported RPM not being accurate when driven outside
the vbios-defined PWM range.
Signed-off-by: Martin Peres <martin.peres@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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I don't know of anything this fixes, but it seems wrong anyway.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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Need to drm_vblank_get/put() the crtc involved in a
pending pageflip, or we might not get vblank irqs and
updates of vblank counts and timestamps for pageflip
events and flip completion.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org
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Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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The blob does not seem to write at that place for my NVAC, though it
does for my NV96, agreeing with what is done in the if/else structure
below. I guess someone forgot to remove the line when the if/else was
put in place.
Signed-off-by: Pierre Moreau <pierre.morrow@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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The specified stride was not correct, resulting in erases overlapping
and part of the zcull regions being not erased at all.
Signed-off-by: Pierre Moreau <pierre.morrow@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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Fixes (at least) PTHERM accesses timing out at higher clock speeds.
Values and registers taken from what the binary driver does.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
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This fixes use-after-free of epi->fllink.next inside list loop macro.
This loop actually releases elements in the body. The list is
rcu-protected but here we cannot hold rcu_read_lock because we need to
lock mutex inside.
The obvious solution is to use list_for_each_entry_safe(). RCU-ness
isn't essential because nobody can change this list under us, it's final
fput for this file.
The bug was introduced by ae10b2b4eb01 ("epoll: optimize EPOLL_CTL_DEL
using rcu")
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Stable <stable@vger.kernel.org> # 3.13+
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Jason Baron <jbaron@akamai.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Changes kASLR from being compile-time selectable (blocked by
CONFIG_HIBERNATION), to being boot-time selectable (with hibernation
available by default) via the "kaslr" kernel command line.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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To support using kernel features that are not compatible with hibernation,
this creates the "nohibernate" kernel boot parameter to disable both
hibernation and resume. This allows hibernation support to be a boot-time
choice instead of only a compile-time choice.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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5fbfbcd3e842d ("cpufreq: cpufreq-cpu0: remove dependency on THERMAL and
REGULATOR") was a little too quick in completely removing the dependency
on the THERMAL driver.
The problem is that while there are inline wrappers to turn the thermal
API calls into empty functions, those do not help if the cpu-thermal
driver is a loadable module and cpufreq-cpu0 is builtin.
Since CONFIG_CPU_THERMAL is a bool option that decides whether the cpu
code is built into the thermal module or not, we have to use a dependency
on the thermal driver itself. However, if CPU_THERMAL is disabled, we
don't need the dependency, hence the strange '!CPU_THERMAL || THERMAL'
construct.
Fixes: 5fbfbcd3e842d ("cpufreq: cpufreq-cpu0: remove dependency on THERMAL and REGULATOR")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Commit 66345d5f79fc (ACPI / ia64 / sba_iommu: Use ACPI scan handler
for device discovery) changed the ordering of SBA (System Bus Adapter)
IOMMU initialization with respect to the PCI host bridge initialization
which broke things inadvertently, because the SBA IOMMU initialization
code has to run after the PCI host bridge has been initialized.
Fix that by reworking the SBA IOMMU ACPI scan handler so that it
claims the discovered matching ACPI device objects without attempting
to initialize anything and move the entire SBA IOMMU initialization
to sba_init() that runs after the PCI bus has been enumerated.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=76691
Fixes: 66345d5f79fc (ACPI / ia64 / sba_iommu: Use ACPI scan handler for device discovery)
Reported-and-tested-by: Émeric Maschino <emeric.maschino@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: 3.11+ <stable@vger.kernel.org> # 3.11+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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of_find_node_by_path() is borked because of_allnodes is not guaranteed to
contain the root of the tree after using any of the dynamic update functions
because some other nodes ends up as of_allnodes.
Fixes: c22e650e66b8 of: Make of_find_node_by_path() handle /aliases
Reported-by: pantelis.antoniou@konsulko.com
Signed-off-by: Frank Rowand <frank.rowand@sonymobile.com>
Signed-off-by: Rob Herring <robh@kernel.org>
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This makes sure a format string cannot leak into the kobject name that
is constructed. (And splits the >80 character line.)
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rob Herring <robh@kernel.org>
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Commit bf5db2f (microblaze: Use generic device.h) removes the
microblaze specific pdev_archdata and dma_mask.
At the same time, commit 591c1ee (of: configure the platform
device dma parameters) initializes the just removed field.
This causes all microblaze builds to fail.
Drop the unnecessary initialization.
Cc: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Rob Herring <robh@kernel.org>
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Only blk-mq completions have payload attached to the request, for
request_fn mode we have stored it in req->special. This fixes an
oops with queue_mode=1 and softirq completions.
Signed-off-by: Jens Axboe <axboe@fb.com>
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'regulator/fix/ltc3589' and 'regulator/fix/palmas' into regulator-linus
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'asoc/fix/pxa', 'asoc/fix/rcar' and 'asoc/fix/sigmadsp' into asoc-linus
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of_find_node_by_name() walks the allnodes list, and can thus walk
outside of the parent node. Use of_get_child_by_name() instead.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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This reverts commit e1edf18b20076da83dd231dbd2146cbbc31c0b14.
This patch was a misguided attempt at fixing offb for LE ppc64
kernels on BE qemu but is just wrong ... it breaks real LE/LE
setups, LE with real HW, and existing mixed endian systems
that did the fight thing with the appropriate device-tree
property. Bad reviewing on my part, sorry.
The right fix is to either make qemu change its endian when
the guest changes endian (working on that) or to use the
existing foreign endian support.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org> [v3.13+]
---
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When a machine is booted with nomodeset option, i915 driver skips the
whole initialization. Meanwhile, HD-audio tries to bind wth i915 just
by request_symbol() without knowing that the initialization was
skipped, and eventually it hits WARN_ON() in i915_request_power_well()
and i915_release_power_well() wrongly but still continues probing,
even though it doesn't work at all.
In this patch, both functions are changed to return an error in case
of uninitialized state instead of WARN_ON(), so that HD-audio driver
can give up HDMI controller initialization at the right time.
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: <stable@vger.kernel.org> [3.15]
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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To ungroup and deregister the group device always use the
ccwgroup_ungroup wrapper.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Since commit 0b60f9ead5d4816e7e3d6e28f4a0d22d4a1b2513
"s390: use device_remove_file_self() instead of device_schedule_callback()"
the return code of ccwgroup_ungroup_store is uninitialized. Make
sure the rc is always initialized.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Commit 0b60f9ead5d4816e7e3d6e28f4a0d22d4a1b2513
"s390: use device_remove_file_self() instead of device_schedule_callback()"
changed ccwgroup to use an extra work queue instead of
device_schedule_callback. This function obtained an extra device
reference for its async work which is missing in the new implementation
and results in a "freeing memory with a lock still held" BUG. Fix
this by obtaining an extra reference for the async work.
Reported-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Keep the per-device dbf entries until module is removed, with
proper error checking for debug feature setup.
Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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The uc_sigmask definition in the kernel differs from the one in the
glibc, the kernel uc_sigmask has 64 bits while the glibc verison
is 1024 bits. The extension of the ucontext structure for 64-bit
register support for 31-bit compat processes added a new field
uc_gprs_high which starts 8 bytes after the uc_sigmask field.
As the glibc view of the ucontext assumes a size of 128 bytes for
uc_sigmask add a 120 byte padding to the kernel structure
ucontext_extended after the 8 byte uc_sigmask.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Currently we set the device name at the time we call device_add after
we receive the interrupt for the first I/O. When something is not working
as expected during that first I/O (e.g. we don't receive an interrupt) we
print a message including the device name which has not yet been
initialized.
Set the device name after calling device_initialize (prior to starting
the first I/O) so that we have the name present if some unexpected error
occurs during that first I/O.
Reported-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reported-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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When the rtmutex fast path is enabled the slow unlock function can
create the following situation:
spin_lock(foo->m->wait_lock);
foo->m->owner = NULL;
rt_mutex_lock(foo->m); <-- fast path
free = atomic_dec_and_test(foo->refcnt);
rt_mutex_unlock(foo->m); <-- fast path
if (free)
kfree(foo);
spin_unlock(foo->m->wait_lock); <--- Use after free.
Plug the race by changing the slow unlock to the following scheme:
while (!rt_mutex_has_waiters(m)) {
/* Clear the waiters bit in m->owner */
clear_rt_mutex_waiters(m);
owner = rt_mutex_owner(m);
spin_unlock(m->wait_lock);
if (cmpxchg(m->owner, owner, 0) == owner)
return;
spin_lock(m->wait_lock);
}
So in case of a new waiter incoming while the owner tries the slow
path unlock we have two situations:
unlock(wait_lock);
lock(wait_lock);
cmpxchg(p, owner, 0) == owner
mark_rt_mutex_waiters(lock);
acquire(lock);
Or:
unlock(wait_lock);
lock(wait_lock);
mark_rt_mutex_waiters(lock);
cmpxchg(p, owner, 0) != owner
enqueue_waiter();
unlock(wait_lock);
lock(wait_lock);
wakeup_next waiter();
unlock(wait_lock);
lock(wait_lock);
acquire(lock);
If the fast path is disabled, then the simple
m->owner = NULL;
unlock(m->wait_lock);
is sufficient as all access to m->owner is serialized via
m->wait_lock;
Also document and clarify the wakeup_next_waiter function as suggested
by Oleg Nesterov.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140611183852.937945560@linutronix.de
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Pull networking fixes from David Miller:
1) Fix checksumming regressions, from Tom Herbert.
2) Undo unintentional permissions changes for SCTP rto_alpha and
rto_beta sysfs knobs, from Denial Borkmann.
3) VXLAN, like other IP tunnels, should advertize it's encapsulation
size using dev->needed_headroom instead of dev->hard_header_len.
From Cong Wang.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
net: sctp: fix permissions for rto_alpha and rto_beta knobs
vxlan: Checksum fixes
net: add skb_pop_rcv_encapsulation
udp: call __skb_checksum_complete when doing full checksum
net: Fix save software checksum complete
net: Fix GSO constants to match NETIF flags
udp: ipv4: do not waste time in __udp4_lib_mcast_demux_lookup
vxlan: use dev->needed_headroom instead of dev->hard_header_len
MAINTAINERS: update cxgb4 maintainer
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git://git.linaro.org/people/mike.turquette/linux
Pull more clock framework updates from Mike Turquette:
"This contains the second half the of the clk changes for 3.16.
They are simply fixes and code refactoring for the OMAP clock drivers.
The sunxi clock driver changes include splitting out the one
mega-driver into several smaller pieces and adding support for the A31
SoC clocks"
* tag 'clk-for-linus-3.16-part2' of git://git.linaro.org/people/mike.turquette/linux: (25 commits)
clk: sunxi: document PRCM clock compatible strings
clk: sunxi: add PRCM (Power/Reset/Clock Management) clks support
clk: sun6i: Protect SDRAM gating bit
clk: sun6i: Protect CPU clock
clk: sunxi: Rework clock protection code
clk: sunxi: Move the GMAC clock to a file of its own
clk: sunxi: Move the 24M oscillator to a file of its own
clk: sunxi: Remove calls to clk_put
clk: sunxi: document new A31 USB clock compatible
clk: sunxi: Implement A31 USB clock
ARM: dts: OMAP5/DRA7: use omap5-mpu-dpll-clock capable of dealing with higher frequencies
CLK: TI: dpll: support OMAP5 MPU DPLL that need special handling for higher frequencies
ARM: OMAP5+: dpll: support Duty Cycle Correction(DCC)
CLK: TI: clk-54xx: Set the rate for dpll_abe_m2x2_ck
CLK: TI: Driver for DRA7 ATL (Audio Tracking Logic)
dt:/bindings: DRA7 ATL (Audio Tracking Logic) clock bindings
ARM: dts: dra7xx-clocks: Correct name for atl clkin3 clock
CLK: TI: gate: add composite interface clock to OMAP2 only build
ARM: OMAP2: clock: add DT boot support for cpufreq_ck
CLK: TI: OMAP2: add clock init support
...
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Pull NVMe update from Matthew Wilcox:
"Mostly bugfixes again for the NVMe driver. I'd like to call out the
exported tracepoint in the block layer; I believe Keith has cleared
this with Jens.
We've had a few reports from people who're really pounding on NVMe
devices at scale, hence the timeout changes (and new module
parameters), hotplug cpu deadlock, tracepoints, and minor performance
tweaks"
[ Jens hadn't seen that tracepoint thing, but is ok with it - it will
end up going away when mq conversion happens ]
* git://git.infradead.org/users/willy/linux-nvme: (22 commits)
NVMe: Fix START_STOP_UNIT Scsi->NVMe translation.
NVMe: Use Log Page constants in SCSI emulation
NVMe: Define Log Page constants
NVMe: Fix hot cpu notification dead lock
NVMe: Rename io_timeout to nvme_io_timeout
NVMe: Use last bytes of f/w rev SCSI Inquiry
NVMe: Adhere to request queue block accounting enable/disable
NVMe: Fix nvme get/put queue semantics
NVMe: Delete NVME_GET_FEAT_TEMP_THRESH
NVMe: Make admin timeout a module parameter
NVMe: Make iod bio timeout a parameter
NVMe: Prevent possible NULL pointer dereference
NVMe: Fix the buffer size passed in GetLogPage(CDW10.NUMD)
NVMe: Update data structures for NVMe 1.2
NVMe: Enable BUILD_BUG_ON checks
NVMe: Update namespace and controller identify structures to the 1.1a spec
NVMe: Flush with data support
NVMe: Configure support for block flush
NVMe: Add tracepoints
NVMe: Protect against badly formatted CQEs
...
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Commit 0fb7a01af5b0 "random: simplify accounting code", introduced in
v3.15, has a very nasty accounting problem when the entropy pool has
has fewer bytes of entropy than the number of requested reserved
bytes. In that case, "have_bytes - reserved" goes negative, and since
size_t is unsigned, the expression:
ibytes = min_t(size_t, ibytes, have_bytes - reserved);
... does not do the right thing. This is rather bad, because it
defeats the catastrophic reseeding feature in the
xfer_secondary_pool() path.
It also can cause the "BUG: spinlock trylock failure on UP" for some
kernel configurations when prandom_reseed() calls get_random_bytes()
in the early init, since when the entropy count gets corrupted,
credit_entropy_bits() erroneously believes that the nonblocking pool
has been fully initialized (when in fact it is not), and so it calls
prandom_reseed(true) recursively leading to the spinlock BUG.
The logic is *not* the same it was originally, but in the cases where
it matters, the behavior is the same, and the resulting code is
hopefully easier to read and understand.
Fixes: 0fb7a01af5b0 "random: simplify accounting code"
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Greg Price <price@mit.edu>
Cc: stable@vger.kernel.org #v3.15
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Commit 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs
to jiffies conversions.") has silently changed permissions for
rto_alpha and rto_beta knobs from 0644 to 0444. The purpose of
this was to discourage users from tweaking rto_alpha and
rto_beta knobs in production environments since they are key
to correctly compute rtt/srtt.
RFC4960 under section 6.3.1. RTO Calculation says regarding
rto_alpha and rto_beta under rule C3 and C4:
[...]
C3) When a new RTT measurement R' is made, set
RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'|
and
SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R'
Note: The value of SRTT used in the update to RTTVAR
is its value before updating SRTT itself using the
second assignment. After the computation, update
RTO <- SRTT + 4 * RTTVAR.
C4) When data is in flight and when allowed by rule C5
below, a new RTT measurement MUST be made each round
trip. Furthermore, new RTT measurements SHOULD be
made no more than once per round trip for a given
destination transport address. There are two reasons
for this recommendation: First, it appears that
measuring more frequently often does not in practice
yield any significant benefit [ALLMAN99]; second,
if measurements are made more often, then the values
of RTO.Alpha and RTO.Beta in rule C3 above should be
adjusted so that SRTT and RTTVAR still adjust to
changes at roughly the same rate (in terms of how many
round trips it takes them to reflect new values) as
they would if making only one measurement per
round-trip and using RTO.Alpha and RTO.Beta as given
in rule C3. However, the exact nature of these
adjustments remains a research issue.
[...]
While it is discouraged to adjust rto_alpha and rto_beta
and not further specified how to adjust them, the RFC also
doesn't explicitly forbid it, but rather gives a RECOMMENDED
default value (rto_alpha=3, rto_beta=2). We have a couple
of users relying on the old permissions before they got
changed. That said, if someone really has the urge to adjust
them, we could allow it with a warning in the log.
Fixes: 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs to jiffies conversions.")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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