* 'usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
USB: Fix usb/isp1760 build on sparc
usb: gadget: epautoconf: do not change number of streams
usb: dwc3: core: fix cached revision on our structure
usb: musb: fix reset issue with full speed device
Currently, the *_global_[un]lock_online() routines are not at all synchronized
with CPU hotplug. Soft-lockups detected as a consequence of this race was
reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng
for finding out that the root-cause of this issue is the race condition
between br_write_[un]lock() and CPU hotplug, which results in the lock states
getting messed up).
Fixing this race by just adding {get,put}_online_cpus() at appropriate places
in *_global_[un]lock_online() is not a good option, because, then suddenly
br_write_[un]lock() would become blocking, whereas they have been kept as
non-blocking all this time, and we would want to keep them that way.
So, overall, we want to ensure 3 things:
1. br_write_lock() and br_write_unlock() must remain as non-blocking.
2. The corresponding lock and unlock of the per-cpu spinlocks must not happen
for different sets of CPUs.
3. Either prevent any new CPU online operation in between this lock-unlock, or
ensure that the newly onlined CPU does not proceed with its corresponding
per-cpu spinlock unlocked.
To achieve all this:
(a) We introduce a new spinlock that is taken by the *_global_lock_online()
routine and released by the *_global_unlock_online() routine.
(b) We register a callback for CPU hotplug notifications, and this callback
takes the same spinlock as above.
(c) We maintain a bitmap which is close to the cpu_online_mask, and once it is
initialized in the lock_init() code, all future updates to it are done in
the callback, under the above spinlock.
(d) The above bitmap is used (instead of cpu_online_mask) while locking and
unlocking the per-cpu locks.
The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the
br_write_lock-unlock sequence is in progress, the callback keeps spinning,
thus preventing the CPU online operation till the lock-unlock sequence is
complete. This takes care of requirement (3).
The bitmap that we maintain remains unmodified throughout the lock-unlock
sequence, since all updates to it are managed by the callback, which takes
the same spinlock as the one taken by the lock code and released only by the
unlock routine. Combining this with (d) above, satisfies requirement (2).
Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug
operations from racing with br_write_lock-unlock, requirement (1) is also
taken care of.
By the way, it is to be noted that a CPU offline operation can actually run
in parallel with our lock-unlock sequence, because our callback doesn't react
to notifications earlier than CPU_DEAD (in order to maintain our bitmap
properly). And this means, since we use our own bitmap (which is stale, on
purpose) during the lock-unlock sequence, we could end up unlocking the
per-cpu lock of an offline CPU (because we had locked it earlier, when the
CPU was online), in order to satisfy requirement (2). But this is harmless,
though it looks a bit awkward.
Debugged-by: Cong Meng <mc@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
net: Add a flow_cache_flush_deferred function
ipv4: reintroduce route cache garbage collector
net: have ipconfig not wait if no dev is available
sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd
asix: new device id
davinci-cpdma: fix locking issue in cpdma_chan_stop
sctp: fix incorrect overflow check on autoclose
r8169: fix Config2 MSIEnable bit setting.
llc: llc_cmsg_rcv was getting called after sk_eat_skb.
net: bpf_jit: fix an off-one bug in x86_64 cond jump target
iwlwifi: update SCD BC table for all SCD queues
Revert "Bluetooth: Revert: Fix L2CAP connection establishment"
Bluetooth: Clear RFCOMM session timer when disconnecting last channel
Bluetooth: Prevent uninitialized data access in L2CAP configuration
iwlwifi: allow to switch to HT40 if not associated
iwlwifi: tx_sync only on PAN context
mwifiex: avoid double list_del in command cancel path
ath9k: fix max phy rate at rate control init
nfc: signedness bug in __nci_request()
iwlwifi: do not set the sequence control bit is not needed
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: atmel/ac97c: using software reset instead hardware reset if not available
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6:
mfd: Include linux/io.h to jz4740-adc
mfd: Use request_threaded_irq for twl4030-irq instead of irq_set_chained_handler
mfd: Base interrupt for twl4030-irq must be one-shot
mfd: Handle tps65910 clear-mask correctly
mfd: add #ifdef CONFIG_DEBUG_FS guard for ab8500_debug_resources
mfd: Fix twl-core oops while calling twl_i2c_* for unbound driver
mfd: include linux/module.h for ab5500-debugfs
mfd: Update wm8994 active device checks for WM1811
mfd: Set tps6586x bits if new value is different from the old one
mfd: Set da903x bits if new value is different from the old one
mfd: Set adp5520 bits if new value is different from the old one
mfd: Add missed free_irq in da903x_remove
* 'for-greg' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb:
usb: gadget: epautoconf: do not change number of streams
usb: dwc3: core: fix cached revision on our structure
usb: musb: fix reset issue with full speed device
This commit:
commit 8f5d621543
Author: Joachim Foerster <joachim.foerster@missinglinkelectronics.com>
Date: Mon Oct 10 18:06:54 2011 +0200
usb/isp1760: Let OF bindings depend on general CONFIG_OF instead of PPC_OF .
To be able to use the driver on other OF-aware architectures, too.
And add necessary OF related #includes to fix compilation error.
Signed-off-by: Joachim Foerster <joachim.foerster@missinglinkelectronics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
enabled the build on all CONFIG_OF architectures, but it cannot do
this.
This driver depends upon CONFIG_OF_IRQ but not all CONFIG_OF platforms
support that infrastructure, in particular Sparc does not so the
build fails.
Please push a patch like the following to Linus so that this code only
gets built where it actually should.
--------------------
usb/isp1760: Add missing CONFIG_OF_IRQ dependency on OF code.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
flow_cach_flush() might sleep but can be called from
atomic context via the xfrm garbage collector. So add
a flow_cache_flush_deferred() function and use this if
the xfrm garbage colector is invoked from within the
packet path.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 2c8cec5c10 (ipv4: Cache learned PMTU information in inetpeer)
removed IP route cache garbage collector a bit too soon, as this gc was
responsible for expired routes cleanup, releasing their neighbour
reference.
As pointed out by Robert Gladewitz, recent kernels can fill and exhaust
their neighbour cache.
Reintroduce the garbage collection, since we'll have to wait our
neighbour lookups become refcount-less to not depend on this stuff.
Reported-by: Robert Gladewitz <gladewitz@gmx.de>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
David and I are sharing maintenance of this repository. Patches
should be sent to both of us.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.infradead.org/mtd-2.6:
mtd: plat_ram: call mtd_device_register only if partition data exists
mtd: pxa2xx-flash.c: It used to fall back to provided table.
mtd: gpmi: add missing include 'module.h'
mtd: ndfc: fix typo in structure dereference
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/clocksource: Fix kernel-doc warnings
rtc: m41t80: Workaround broken alarm functionality
rtc: Expire alarms after the time is set.
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
* 'stable/for-linus-fixes-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
Revert "xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernel"
Linus Torvalds
David Miller
Stephen Rothwell
Srivatsa S. Bhat
Dave Kleikamp
Greg Kroah-Hartman
Steffen Klassert
Eric Dumazet
John W. Linville
Ben Hutchings
David Howells
James Morris