Instead of overloading __blk_run_queue to force an offload to kblockd
add a new blk_run_queue_async helper to do it explicitly. I've kept
the blk_queue_stopped check for now, but I suspect it's not needed
as the check we do when the workqueue items runs should be enough.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
A dynamic posix clock is protected from asynchronous removal by a mutex.
However, using a mutex has the unwanted effect that a long running clock
operation in one process will unnecessarily block other processes.
For example, one process might call read() to get an external time stamp
coming in at one pulse per second. A second process calling clock_gettime
would have to wait for almost a whole second.
This patch fixes the issue by using a reader/writer semaphore instead of
a mutex.
Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/%3C20110330132421.GA31771%40riccoc20.at.omicron.at%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Now that unplugging is done differently, the unplug_fn callback is
never called, so it can be completely discarded.
Signed-off-by: NeilBrown <neilb@suse.de>
MD can't use this since it really requires us to be able to
keep more than a single piece of state for the unplug. Commit
048c9374 added the required support for MD, so get rid of this
now unused code.
This reverts commit f75664570d.
Conflicts:
block/blk-core.c
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
md/raid requires an unplug callback, but as it does not uses
requests the current code cannot provide one.
So allow arbitrary callbacks to be attached to the blk_plug.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: make unplug timer trace event correspond to the schedule() unplug
block: let io_schedule() flush the plug inline
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf_event: Fix cgrp event scheduling bug in perf_enable_on_exec()
perf: Fix a build error with some GCC versions
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Fix erroneous all_pinned logic
sched: Fix sched-domain avg_load calculation
* 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
RTC: rtc-mrst: follow on to the change of rtc_device_register()
RTC: add missing "return 0" in new alarm func for rtc-bfin.c
RTC: Fix s3c compile error due to missing s3c_rtc_setpie
RTC: Fix early irqs caused by calling rtc_set_alarm too early
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, amd: Disable GartTlbWlkErr when BIOS forgets it
x86, NUMA: Fix fakenuma boot failure
x86/mrst: Fix boot crash caused by incorrect pin to irq mapping
x86/ce4100: Add reg property to bridges
It's a pretty close match to what we had before - the timer triggering
would mean that nobody unplugged the plug in due time, in the new
scheme this matches very closely what the schedule() unplug now is.
It's essentially the difference between an explicit unplug (IO unplug)
or an implicit unplug (timer unplug, we scheduled with pending IO
queued).
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Linus correctly observes that the most important dispatch cases
are now done from kblockd, this isn't ideal for latency reasons.
The original reason for switching dispatches out-of-line was to
avoid too deep a stack, so by _only_ letting the "accidental"
flush directly in schedule() be guarded by offload to kblockd,
we should be able to get the best of both worlds.
So add a blk_schedule_flush_plug() that offloads to kblockd,
and only use that from the schedule() path.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric VAn Hensbergen <ericvh@gmail.com>
Now that we use write_inode to flush server
cache related to fid, we don't need tsyncfs either fort dotl or dotu
protocols. For dotu this helps to do a more efficient server flush.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: only force kblockd unplugging from the schedule() path
block: cleanup the block plug helper functions
block, blk-sysfs: Use the variable directly instead of a function call
block: move queue run on unplug to kblockd
block: kill queue_sync_plugs()
block: readd plug trace event
block: add callback function for unplug notification
block: add comment on why we save and disable interrupts in flush_plug_list()
block: fixup block IO unplug trace call
block: remove block_unplug_timer() trace point
block: splice plug list to local context
For the explicit unplugging, we'd prefer to kick things off
immediately and not pay the penalty of the latency to switch
to kblockd. So let blk_finish_plug() do the run inline, while
the implicit-on-schedule-out unplug will punt to kblockd.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
It's a bit of a mess currently. task->plug is being cleared
and reset in __blk_finish_plug(), and blk_finish_plug() is
testing for a NULL plug which cannot happen even from schedule()
anymore since it uses blk_needs_flush_plug() to determine
whether to call into this function at all.
So get rid of some of the cruft.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Fix a possible problem with mport registration left non-cleared after
fsl_rio_setup() exits on link error. Abort mport initialization if
registration failed.
This patch is applicable to 2.6.39-rc1 only. The problem does not exist
for earlier versions.
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
5520e89 ("brk: fix min_brk lower bound computation for COMPAT_BRK")
tried to get the whole logic of brk randomization for legacy
(libc5-based) applications finally right.
It turns out that the way to detect whether brk has actually been
randomized in the end or not introduced by that patch still doesn't work
for those binaries, as reported by Geert:
: /sbin/init from my old m68k ramdisk exists prematurely.
:
: Before the patch:
:
: | brk(0x80005c8e) = 0x80006000
:
: After the patch:
:
: | brk(0x80005c8e) = 0x80005c8e
:
: Old libc5 considers brk() to have failed if the return value is not
: identical to the requested value.
I don't like it, but currently see no better option than a bit flag in
task_struct to catch the CONFIG_COMPAT_BRK && randomize_va_space == 2
case.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I found it difficult to make sense of transparent huge pages without
having any counters for its actions. Add some counters to vmstat for
allocation of transparent hugepages and fallback to smaller pages.
Optional patch, but useful for development and understanding the system.
Contains improvements from Andrea Arcangeli and Johannes Weiner
[akpm@linux-foundation.org: coding-style fixes]
[hannes@cmpxchg.org: fix vmstat_text[] entries]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit 3f58a82943 ("move memcg reclaimable page into tail of inactive
list") added inline keyword twice in its prototype.
CC arch/x86/kernel/asm-offsets.s
In file included from include/linux/swap.h:8,
from include/linux/suspend.h:4,
from arch/x86/kernel/asm-offsets.c:12:
include/linux/memcontrol.h:220: error: duplicate `inline'
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
USB tethering does not work anymore since 2.6.39-rc2, but it's okay in
-rc1. The root cause is the new added mask code 'FLAG_POINTTOPOINT'
overlaps 'FLAG_MULTI_PACKET' in include/linux/usb/usbnet.h, this
causes logic issue in rx_process(). This patch cleans up the overlap.
Reported-and-Tested-by: Gottfried Haider <gottfried.haider@gmail.com>
Signed-off-by: Huajun Li <huajun.li.lee@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new EV_SYN code, SYN_DROPPED, to inform the client when input
events have been dropped from the evdev input buffer due to a
buffer overrun. The client should use this event as a hint to
reset its state or ignore all following events until the next
packet begins.
Signed-off-by: Jeff Brown <jeffbrown@android.com>
[dtor@mail.ru: Implement Henrik's suggestion and drop old events in
case of overflow.]
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Many media center remotes have buttons intended for jumping straight to
one type of media browser or another -- commonly, images/photos/pictures,
audio/music, television, and movies. At present, remotes with an images
or photos or pictures button use any number of different keycodes which
sort of maybe fit. I've seen at least KEY_MEDIA, KEY_CAMERA,
KEY_GRAPHICSEDITOR and KEY_PRESENTATION. None of those seem quite right.
In my mind, KEY_MEDIA should be something more like a media center
application launcher (and I'd like to standardize on that for things
like the windows media center button on the mce remotes). KEY_CAMERA is
used in a lot of webcams, and typically means "take a picture now".
KEY_GRAPHICSEDITOR implies an editor, not a browser. KEY_PRESENTATION
might be the closest fit here, if you think "photo slide show", but it
may well be more intended for "run application in full-screen
presentation mode" or to launch something like magicpoint, I dunno.
And thus, I'd like to have a KEY_IMAGES, which matches the HID Usage AL
Image Browser, the meaning of which I think is crystal-clear. I believe
AL Audio Browser is already covered by KEY_AUDIO, and AL Movie Browser
by KEY_VIDEO, so I'm also adding appropriate comments next to those
keys.
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Gaah. When commit be85bccaa5 reverted the export of file system uuid
via /proc/<pid>/mountinfo, it also unintentionally removed the s_uuid
field in struct super_block.
I didn't mean to do that, since filesystems have been taught to fill it
in (and we want to keep it for future re-introduction in the mountinfo
file).
Stupid of me. This adds it back in.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 93f1c20bc8.
It turns out that libmount misparses it because it adds a '-' character
in the uuid string, which libmount then incorrectly confuses with the
separator string (" - ") at the end of all the optional arguments.
Upstream libmount (in the util-linux tree) has been fixed, but until
that fix actually percolates up to users, we'd better not expose this
change in the kernel.
Let's revisit this later (possibly by exposing the UUID without any '-'
characters in it, avoiding the user-space bug).
Reported-by: Dave Jones <davej@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Karel Zak <kzak@redhat.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order for MFD drivers to fetch their cell pointer but also their
platform data one, an mfd cell pointer is added to the platform_device
structure.
That allows all MFD sub devices drivers to be MFD agnostic, unless
they really need to access their MFD cell data. Most of them don't,
especially the ones for IPs used by both MFD and non MFD SoCs.
Cc: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Greg KH <gregkh@suse.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
MD would like to know when a queue is unplugged, so it can flush
it's bitmap writes. Add such a callback.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
It was removed with the on-stack plugging, readd it and track the
depth of requests added when flushing the plug.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Xen save/restore is going to use hibernate device callbacks for
quiescing devices and putting them back to normal operations and it
would need to select CONFIG_HIBERNATION for this purpose. However,
that also would cause the hibernate interfaces for user space to be
enabled, which might confuse user space, because the Xen kernels
don't support hibernation. Moreover, it would be wasteful, as it
would make the Xen kernels include a substantial amount of code that
they would never use.
To address this issue introduce new power management Kconfig option
CONFIG_HIBERNATE_CALLBACKS, such that it will only select the code
that is necessary for the hibernate device callbacks to work and make
CONFIG_HIBERNATION select it. Then, Xen save/restore will be able to
select CONFIG_HIBERNATE_CALLBACKS without dragging the entire
hibernate code along with it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (34 commits)
net: Add support for SMSC LAN9530, LAN9730 and LAN89530
mlx4_en: Restoring RX buffer pointer in case of failure
mlx4: Sensing link type at device initialization
ipv4: Fix "Set rt->rt_iif more sanely on output routes."
MAINTAINERS: add entry for Xen network backend
be2net: Fix suspend/resume operation
be2net: Rename some struct members for clarity
pppoe: drop PPPOX_ZOMBIEs in pppoe_flush_dev
dsa/mv88e6131: add support for mv88e6085 switch
ipv6: Enable RFS sk_rxhash tracking for ipv6 sockets (v2)
be2net: Fix a potential crash during shutdown.
bna: Fix for handling firmware heartbeat failure
can: mcp251x: Allow pass IRQ flags through platform data.
smsc911x: fix mac_lock acquision before calling smsc911x_mac_read
iwlwifi: accept EEPROM version 0x423 for iwl6000
rt2x00: fix cancelling uninitialized work
rtlwifi: Fix some warnings/bugs
p54usb: IDs for two new devices
wl12xx: fix potential buffer overflow in testmode nvs push
zd1211rw: reset rx idle timer from tasklet
...
Commit 1018b5c016 ("Set rt->rt_iif more
sanely on output routes.") breaks rt_is_{output,input}_route.
This became the cause to return "IP_PKTINFO's ->ipi_ifindex == 0".
To fix it, this does:
1) Add "int rt_route_iif;" to struct rtable
2) For input routes, always set rt_route_iif to same value as rt_iif
3) For output routes, always set rt_route_iif to zero. Set rt_iif
as it is done currently.
4) Change rt_is_{output,input}_route() to test rt_route_iif
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
When an interrupt occurs, the INT pin is driven low by the
MCP251x controller (falling edge) but in some cases the INT
pin can be connected to the MPU through a transistor or level
translator which inverts this signal. In this case interrupt
should be configured in rising edge.
This patch adds support to pass the IRQ flags via
mcp251x_platform_data.
Signed-off-by: Enric Balletbo i Serra <eballetbo@iseebcn.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-2.6-block:
ide: always ensure that blk_delay_queue() is called if we have pending IO
block: fix request sorting at unplug
dm: improve block integrity support
fs: export empty_aops
ide: ide_requeue_and_plug() reinstate "always plug" behaviour
blk-throttle: don't call xchg on bool
ufs: remove unessecary blk_flush_plug
block: make the flush insertion use the tail of the dispatch list
block: get rid of elv_insert() interface
block: dump request state on seeing a corrupted request completion
The current block integrity (DIF/DIX) support in DM is verifying that
all devices' integrity profiles match during DM device resume (which
is past the point of no return). To some degree that is unavoidable
(stacked DM devices force this late checking). But for most DM
devices (which aren't stacking on other DM devices) the ideal time to
verify all integrity profiles match is during table load.
Introduce the notion of an "initialized" integrity profile: a profile
that was blk_integrity_register()'d with a non-NULL 'blk_integrity'
template. Add blk_integrity_is_initialized() to allow checking if a
profile was initialized.
Update DM integrity support to:
- check all devices with _initialized_ integrity profiles match
during table load; uninitialized profiles (e.g. for underlying DM
device(s) of a stacked DM device) are ignored.
- disallow a table load that would result in an integrity profile that
conflicts with a DM device's existing (in-use) integrity profile
- avoid clearing an existing integrity profile
- validate all integrity profiles match during resume; but if they
don't all we can do is report the mismatch (during resume we're past
the point of no return)
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
With the ->sync_page() hook gone, we have a few users that
add their own static address_space_operations without any
functions defined.
fs/inode.c already has an empty_aops that it uses for init
purposes. Lets export that and use it in the places where
an otherwise empty aops was defined.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Merge it with __elv_add_request(), it's pretty pointless to
have a function with only two callers. The main interface
is elv_add_request()/__elv_add_request().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (27 commits)
ipv6: Don't pass invalid dst_entry pointer to dst_release().
mlx4: fix kfree on error path in new_steering_entry()
tcp: len check is unnecessarily devastating, change to WARN_ON
sctp: malloc enough room for asconf-ack chunk
sctp: fix auth_hmacs field's length of struct sctp_cookie
net: Fix dev dev_ethtool_get_rx_csum() for forced NETIF_F_RXCSUM
usbnet: use eth%d name for known ethernet devices
starfire: clean up dma_addr_t size test
iwlegacy: fix bugs in change_interface
carl9170: Fix tx aggregation problems with some clients
iwl3945: disable hw scan by default
wireless: rt2x00: rt2800usb.c add and identify ids
iwl3945: do not deprecate software scan
mac80211: fix aggregation frame release during timeout
cfg80211: fix BSS double-unlinking (continued)
cfg80211:: fix possible NULL pointer dereference
mac80211: fix possible NULL pointer dereference
mac80211: fix NULL pointer dereference in ieee80211_key_alloc()
ath9k: fix a chip wakeup related crash in ath9k_start
mac80211: fix a crash in minstrel_ht in HT mode with no supported MCS rates
...
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm: fix "persistant" typo
drm/radeon/kms: add some new ontario pci ids
drm/radeon/kms: pageflipping cleanup for avivo+
drm/radeon/kms: Add support for tv-out dongle on G5 9600
drm: export drm_find_cea_extension to drivers
drm/radeon/kms: add some sanity checks to obj info record parsingi (v2)
drm/i915: Reset GMBUS controller after NAK
drm/i915: Busy-spin wait_for condition in atomic contexts
drm/i915/lvds: Always return connected in the absence of better information
The description for buf_size was misleading and
just said you couldn't TX larger aggregates, but
of course you can't TX aggregates in a way that
would exceed the window either, which is possible
even if the aggregates are shorter than that.
Expand the description, thanks to Emmanuel for
explaining this to me.
Cc: Emmanuel Grumbach <egrumbach@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, UV: Fix kdump reboot
x86, amd-nb: Rename CPU PCI id define for F4
sound: Add delay.h to sound/soc/codecs/sn95031.c
x86, mtrr, pat: Fix one cpu getting out of sync during resume
x86, microcode: Unregister syscore_ops after microcode unloaded
x86: Stop including <linux/delay.h> in two asm header files
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: create new rcu_access_index() and use in mce
WARN_ON_SMP(): Add comment to explain ({0;})
ipv6 fib lookup can set RT6_LOOKUP_F_IFACE flag to restrict search
to an interface, but this flag cannot be set via struct flowi.
Also, it cannot be set via ip6_route_output: this function uses the
passed sock struct to determine if this flag is required
(by testing for nonzero sk_bound_dev_if).
Work around this by passing in an artificial struct sk in case
'strict' argument is true.
This is required to replace the rt6_lookup call in xt_addrtype.c with
nf_afinfo->route().
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This is required to eventually replace the rt6_lookup call in
xt_addrtype.c with nf_afinfo->route().
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>
ipvsadm -ln --daemon will trigger a Null pointer exception because
ip_vs_genl_dump_daemons() uses skb_net() instead of skb_sknet().
To prevent others from NULL ptr a check is made in ip_vs.h skb_net().
Signed-off-by: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>
The timeout variant of the list:set type must reference the member sets.
However, its garbage collector runs at timer interrupt so the mutex
protection of the references is a no go. Therefore the reference protection
is converted to rwlock.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
auth_hmacs field of struct sctp_cookie is used for store
Requested HMAC Algorithm Parameter, and each HMAC Identifier
is 2 bytes, so the length should be:
SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
dev_ethtool_get_rx_csum() won't report rx checksumming when it's not
changeable and driver is converted to hw_features and friends. Fix this.
(dev->hw_features & NETIF_F_RXCSUM) check is dropped - if the
ethtool_ops->get_rx_csum is set, then driver is not coverted, yet.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
The documentation for the USB ethernet devices suggests that
only some devices are supposed to use usb0 as the network interface
name instead of eth0. The logic used there, and documented in
Kconfig for CDC is that eth0 will be used when the mac address
is a globally assigned one, but usb0 is used for the locally
managed range that is typically used on point-to-point links.
Unfortunately, this has caused a lot of pain on the smsc95xx
device that is used on the popular pandaboard without an
EEPROM to store the MAC address, which causes the driver to
call random_ether_address().
Obviously, there should be a proper MAC addressed assigned to
the device, and discussions are ongoing about how to solve
this, but this patch at least makes sure that the default
interface naming gets a little saner and matches what the
user can expect based on the documentation, including for
new devices.
The approach taken here is to flag whether a device might be a
point-to-point link with the new FLAG_POINTTOPOINT setting in
the usbnet driver_info. A driver can set both FLAG_POINTTOPOINT
and FLAG_ETHER if it is not sure (e.g. cdc_ether), or just one
of the two. The usbnet framework only looks at the MAC address
for device naming if both flags are set, otherwise it trusts the
flag.
Signed-off-by: Arnd Bergmann <arnd.bergmann@linaro.org>
Tested-by: Andy Green <andy.green@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: pcm: fix infinite loop in snd_pcm_update_hw_ptr0()
ALSA: HDA: Add dock mic quirk for Lenovo Thinkpad X220
ALSA: ens1371: fix Creative Ectiva support
ALSA: firewire-speakers: fix hang when unplugging a running device
ASoC: Fix CODEC device name for Corgi
ALSA: hda - Fix pin-config of Gigabyte mobo
ASoC: imx: fix burstsize for DMA
ASoC: imx: set watermarks for mx2-dma
ASoC: twl6040: Return -ENOMEM if create_singlethread_workqueue fails
ASoC: tlv320dac33: Restore L/R DAC power control register
ASoC: Explicitly say registerless widgets have no register
ASoC: tlv320dac33: Fix inconsistent spinlock usage
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
kdump: Allow shrinking of kdump region to be overridden
powerpc/pmac/smp: Remove no-longer needed preempt workaround
powerpc/smp: Increase vdso_data->processorCount, not just decrease it
powerpc/smp: Create idle threads on demand and properly reset them
powerpc/smp: Don't expose per-cpu "cpu_state" array
powerpc/pmac/smp: Fix CPU hotplug crashes on some machines
powerpc/smp: Add a smp_ops->bringup_up() done callback
powerpc/pmac: Rename cpu_state in therm_pm72 to avoid collision
powerpc/pmac/smp: Properly NAP offlined CPU on G5
powerpc/pmac/smp: Remove HMT changes for PowerMac offline code
powerpc/pmac/smp: Consolidate 32-bit and 64-bit PowerMac cpu_die in one file
powerpc/pmac/smp: Fixup smp_core99_cpu_disable() and use it on 64-bit
powerpc/pmac/smp: Rename fixup_irqs() to migrate_irqs() and use it on ppc32
powerpc/pmac/smp: Fix 32-bit PowerMac cpu_die
powerpc/smp: Remove unused smp_ops->cpu_enable()
powerpc/smp: Remove unused generic_cpu_enable()
powerpc/smp: Fix generic_mach_cpu_die()
powerpc/smp: soft-replugged CPUs must go back to start_secondary
powerpc: Make decrementer interrupt robust against offlined CPUs
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
appletalk: Fix OOPS in atalk_release().
mlx4: Fixing bad size of event queue buffer
mlx4: Fixing use after free
bonding:typo in comment
sctp: Pass __GFP_NOWARN to hash table allocation attempts.
connector: convert to synchronous netlink message processing
fib: add rtnl locking in ip_fib_net_exit
atm/solos-pci: Don't flap VCs when carrier state changes
atm/solos-pci: Don't include frame pseudo-header on transmit hex-dump
atm/solos-pci: Use VPI.VCI notation uniformly.
Atheros, atl2: Fix mem leaks in error paths of atl2_set_eeprom
netdev: fix mtu check when TSO is enabled
net/usb: Ethernet quirks for the LG-VL600 4G modem
phylib: phy_attach_direct: phy_init_hw can fail, add cleanup
bridge: mcast snooping, fix length check of snooped MLDv1/2
via-ircc: Pass PCI device pointer to dma_{alloc, free}_coherent()
via-ircc: Use pci_{get, set}_drvdata() instead of static pointer variable
net: gre: provide multicast mappings for ipv4 and ipv6
bridge: Fix compilation warning in function br_stp_recalculate_bridge_id()
net: Fix warnings caused by MAX_SKB_FRAGS change.
The MCE subsystem needs to sample an RCU-protected index outside of
any protection for that index. If this was a pointer, we would use
rcu_access_pointer(), but there is no corresponding rcu_access_index().
This commit therefore creates an rcu_access_index() and applies it
to MCE.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Zdenek Kabelac <zkabelac@redhat.com>
On ppc64 the crashkernel region almost always overlaps an area of firmware.
This works fine except when using the sysfs interface to reduce the kdump
region. If we free the firmware area we are guaranteed to crash.
Rename free_reserved_phys_range to crash_free_reserved_phys_range and make
it a weak function so we can override it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Nouveau needs access to this structure to build an ELD block for use
by the HDA audio codec.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Jiri reported:
|
| - once an event is created by sys_perf_event_open, task context
| is created and it stays even if the event is closed, until the
| task is finished ... thats what I see in code and I assume it's
| correct
|
| - when the task opens event, perf_sched_events jump label is
| incremented and following callbacks are started from scheduler
|
| __perf_event_task_sched_in
| __perf_event_task_sched_out
|
| These callback *in/out set/unset cpuctx->task_ctx value to the
| task context.
|
| - close is called on event on CPU 0:
| - the task is scheduled on CPU 0
| - __perf_event_task_sched_in is called
| - cpuctx->task_ctx is set
| - perf_sched_events jump label is decremented and == 0
| - __perf_event_task_sched_out is not called
| - cpuctx->task_ctx on CPU 0 stays set
|
| - exit is called on CPU 1:
| - the task is scheduled on CPU 1
| - perf_event_exit_task is called
| - task_ctx_sched_out unsets cpuctx->task_ctx on CPU 1
| - put_ctx destroys the context
|
| - another call of perf_rotate_context on CPU 0 will use invalid
| task_ctx pointer, and eventualy panic.
|
Cure this the simplest possibly way by partially reverting the
jump_label optimization for the sched_out case.
Reported-and-tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@kernel.org> # .37+
LKML-Reference: <1301520405.4859.213.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With increasing number of PCI function ids, add the PCI function
id in the define name instead of its symbolic name in the BKDG
for more clarity. This renames function 4 define.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <20110330183447.GA3668@aftab>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commits 01a16b21 (netlink: kill eff_cap from struct netlink_skb_parms)
and c53fa1ed (netlink: kill loginuid/sessionid/sid members from struct
netlink_skb_parms) removed some members from struct netlink_skb_parms
that depend on the current context, all netlink users are now required
to do synchronous message processing.
connector however queues received messages and processes them in a work
queue, which is not valid anymore. This patch converts connector to do
synchronous message processing by invoking the registered callback handler
directly from the netlink receive function.
In order to avoid invoking the callback with connector locks held, a
reference count is added to struct cn_callback_entry, the reference
is taken when finding a matching callback entry on the device's queue_list
and released after the callback handler has been invoked.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Don't flap VCs when carrier state changes; higher-level protocols
can detect loss of connectivity and act accordingly. This is more
consistent with how other network interfaces work.
We no longer use release_vccs() so we can delete it.
release_vccs() was duplicated from net/atm/common.c; make the
corresponding function exported, since other code duplicates it
and could leverage it if it were public.
Signed-off-by: Philip A. Prindeville <philipp@redfish-solutions.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
libceph: Create a new key type "ceph".
libceph: Get secret from the kernel keys api when mounting with key=NAME.
ceph: Move secret key parsing earlier.
libceph: fix null dereference when unregistering linger requests
ceph: unlock on error in ceph_osdc_start_request()
ceph: fix possible NULL pointer dereference
ceph: flush msgr_wq during mds_client shutdown
This adds a driver for the CDC Ethernet part of this modem. The
device's ID is blacklisted in cdc_ether.c and is white-listed in
this new driver because of the quirks needed to make it useful.
The modem's firmware exposes a CDC ACM port for modem control and a
CDC Ethernet port for network data. The descriptors look fine but
both ports actually are some sort of multiplexers requiring non-
standard headers added/removed from every packet or they get
ignored. All information is based on a usb traffic log from a
Windows machine.
On the Verizon 4G network I've seen speeds up to 1.1MB/s so far with
this driver, a speed-o-meter site reports 16.2Mbps/10.5Mbps.
Userspace scripts are required to talk to the CDC ACM port.
Signed-off-by: Andrzej Zaborowski <balrogg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
My commit 6d55cb91a0 (gre: fix hard header destination
address checking) broke multicast.
The reason is that ip_gre used to get ipgre_header() calls with
zero destination if we have NOARP or multicast destination. Instead
the actual target was decided at ipgre_tunnel_xmit() time based on
per-protocol dissection.
Instead of allowing the "abuse" of ->header() calls with invalid
destination, this creates multicast mappings for ip_gre. This also
fixes "ip neigh show nud noarp" to display the proper multicast
mappings used by the gre device.
Reported-by: Doug Kehn <rdkehn@yahoo.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Acked-by: Doug Kehn <rdkehn@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After commit a715dea3c8 ("net: Always
allocate at least 16 skb frags regardless of page size"), the value
of MAX_SKB_FRAGS can now take on either an "unsigned long" or an
"int" value.
This causes warnings like:
net/packet/af_packet.c: In function ‘tpacket_fill_skb’:
net/packet/af_packet.c:948: warning: format ‘%lu’ expects type ‘long unsigned int’, but argument 2 has type ‘int’
Fix by forcing the constant to be unsigned long, otherwise we have
a situation where the type of a system wide constant is variable.
Signed-off-by: David S. Miller <davem@davemloft.net>
When we register an rtc device at boot, we read the alarm value
in hardware and set the rtc device's aie_timer to that value.
The initial method to do this was to simply call rtc_set_alarm()
with the value read from hardware. However, this may cause problems
as rtc_set_alarm may enable interupts, and the RTC alarm might fire,
which can cause invalid pointer dereferencing since the RTC registration
is not complete.
This patch solves the issue by initializing the rtc_device.aie_timer
y hand via rtc_initialize_alarm(). This avoids any calls to the RTC
hardware which might enable interrupts too early.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This allows us to use existence of the key type as a feature test,
from userspace.
Signed-off-by: Tommi Virtanen <tommi.virtanen@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>
This makes the base64 logic be contained in mount option parsing,
and prepares us for replacing the homebew key management with the
kernel key retention service.
Signed-off-by: Tommi Virtanen <tommi.virtanen@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc: (26 commits)
mmc: SDHI should depend on SUPERH || ARCH_SHMOBILE
mmc: tmio_mmc: Move some defines into a shared header
mmc: tmio: support aggressive clock gating
mmc: tmio: fix power-mode interpretation
mmc: tmio: remove work-around for unmasked SDIO interrupts
sh: fix SDHI IO address-range
ARM: mach-shmobile: fix SDHI IO address-range
mmc: tmio: only access registers above 0xff, if available
mfd: remove now redundant sh_mobile_sdhi.h header
sh: convert boards to use linux/mmc/sh_mobile_sdhi.h
ARM: mach-shmobile: convert boards to use linux/mmc/sh_mobile_sdhi.h
mmc: tmio: convert the SDHI MMC driver from MFD to a platform driver
sh: ecovec: use the CONFIG_MMC_TMIO symbols instead of MFD
mmc: tmio: split core functionality, DMA and MFD glue
mmc: tmio: use PIO for short transfers
mmc: tmio-mmc: Improve DMA stability on sh-mobile
mmc: fix mmc_app_send_scr() for dma transfer
mmc: sdhci-esdhc: enable esdhc on imx53
mmc: sdhci-esdhc: use writel/readl as general APIs
mmc: sdhci: add the abort CMDTYPE bits definition
...
* 'frv' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-frv:
FRV: Use generic show_interrupts()
FRV: Convert genirq namespace
frv: Select GENERIC_HARDIRQS_NO_DEPRECATED
frv: Convert cpu irq_chip to new functions
frv: Convert mb93493 irq_chip to new functions
frv: Convert mb93093 irq_chip to new function
frv: Convert mb93091 irq_chip to new functions
frv: Fix typo from __do_IRQ overhaul
frv: Remove stale irq_chip.end
FRV: Do some cleanups
FRV: Missing node arg in alloc_thread_info_node() macro
NOMMU: implement access_remote_vm
NOMMU: support SMP dynamic percpu_alloc
NOMMU: percpu should use is_vmalloc_addr().
* 'irq-final-for-linus-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (111 commits)
gpio: ab8500: Mark broken
genirq: Remove move_*irq leftovers
genirq: Remove compat code
drivers: Final irq namespace conversion
mn10300: Use generic show_interrupts()
mn10300: Cleanup irq_desc access
mn10300: Convert genirq namespace
frv: Use generic show_interrupts()
frv: Convert genirq namespace
frv: Select GENERIC_HARDIRQS_NO_DEPRECATED
frv: Convert cpu irq_chip to new functions
frv: Convert mb93493 irq_chip to new functions
frv: Convert mb93093 irq_chip to new function
frv: Convert mb93091 irq_chip to new functions
frv: Fix typo from __do_IRQ overhaul
frv: Remove stale irq_chip.end
m68k: Convert irq function namespace
xen: Use new irq_move functions
xen: Cleanup genirq namespace
unicore32: Use generic show_interrupts()
...
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (30 commits)
xfrm: Restrict extended sequence numbers to esp
xfrm: Check for esn buffer len in xfrm_new_ae
xfrm: Assign esn pointers when cloning a state
xfrm: Move the test on replay window size into the replay check functions
netdev: bfin_mac: document TE setting in RMII modes
drivers net: Fix declaration ordering in inline functions.
cxgb3: Apply interrupt coalescing settings to all queues
net: Always allocate at least 16 skb frags regardless of page size
ipv4: Don't ip_rt_put() an error pointer in RAW sockets.
net: fix ethtool->set_flags not intended -EINVAL return value
mlx4_en: Fix loss of promiscuity
tg3: Fix inline keyword usage
tg3: use <linux/io.h> and <linux/uaccess.h> instead <asm/io.h> and <asm/uaccess.h>
net: use CHECKSUM_NONE instead of magic number
Net / jme: Do not use legacy PCI power management
myri10ge: small rx_done refactoring
bridge: notify applications if address of bridge device changes
ipv4: Fix IP timestamp option (IPOPT_TS_PRESPEC) handling in ip_options_echo()
can: c_can: Fix tx_bytes accounting
can: c_can_platform: fix irq check in probe
...
When we clone a xfrm state we have to assign the replay_esn
and the preplay_esn pointers to the state if we use the
new replay detection method. To this end, we add a
xfrm_replay_clone() function that allocates memory for
the replay detection and takes over the necessary values
from the original state.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
When analysing performance of the cxgb3 on a ppc64 box I noticed that
we weren't doing much GRO merging. It turns out we are limited by the
number of SKB frags:
#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 2)
With a 4kB page size we have 18 frags, but with a 64kB page size we
only have 3 frags.
I ran a single stream TCP bandwidth test to compare the performance of
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'irq-cleanup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
vlynq: Convert irq functions
* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq; Fix cleanup fallout
genirq: Fix typo and remove unused variable
genirq: Fix new kernel-doc warnings
genirq: Add setter for AFFINITY_SET in irq_data state
genirq: Provide setter inline for IRQD_IRQ_INPROGRESS
genirq: Remove handle_IRQ_event
arm: Ns9xxx: Remove private irq flow handler
powerpc: cell: Use the core flow handler
genirq: Provide edge_eoi flow handler
genirq: Move INPROGRESS, MASKED and DISABLED state flags to irq_data
genirq: Split irq_set_affinity() so it can be called with lock held.
genirq: Add chip flag for restricting cpu_on/offline calls
genirq: Add chip hooks for taking CPUs on/off line.
genirq: Add irq disabled flag to irq_data state
genirq: Reserve the irq when calling irq_set_chip()
* 'for-linus-unmerged' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (45 commits)
Btrfs: fix __btrfs_map_block on 32 bit machines
btrfs: fix possible deadlock by clearing __GFP_FS flag
btrfs: check link counter overflow in link(2)
btrfs: don't mess with i_nlink of unlocked inode in rename()
Btrfs: check return value of btrfs_alloc_path()
Btrfs: fix OOPS of empty filesystem after balance
Btrfs: fix memory leak of empty filesystem after balance
Btrfs: fix return value of setflags ioctl
Btrfs: fix uncheck memory allocations
btrfs: make inode ref log recovery faster
Btrfs: add btrfs_trim_fs() to handle FITRIM
Btrfs: adjust btrfs_discard_extent() return errors and trimmed bytes
Btrfs: make btrfs_map_block() return entire free extent for each device of RAID0/1/10/DUP
Btrfs: make update_reserved_bytes() public
btrfs: return EXDEV when linking from different subvolumes
Btrfs: Per file/directory controls for COW and compression
Btrfs: add datacow flag in inode flag
btrfs: use GFP_NOFS instead of GFP_KERNEL
Btrfs: check return value of read_tree_block()
btrfs: properly access unaligned checksum buffer
...
Fix up trivial conflicts in fs/btrfs/volumes.c due to plug removal in
the block layer.
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mjg59/platform-drivers-x86: (81 commits)
xo15-ebook: Remove device.wakeup_count
ips: use interruptible waits in ips-monitor
acer-wmi: does not poll device status when WMI event is available
acer-wmi: does not set persistence state by rfkill_init_sw_state
platform-drivers: x86: fix common misspellings
acer-wmi: use pr_<level> for messages
asus-wmi: potential NULL dereference in show_call()
asus-wmi: signedness bug in read_brightness()
platform-driver-x86: samsung-laptop: make dmi_check_cb to return 1 instead of 0
platform-driver-x86: fix wrong merge for compal-laptop.c
msi-laptop: use pr_<level> for messages
Platform: add Samsung Laptop platform driver
acer-wmi: Fix WMI ID
acer-wmi: deactive mail led when power off
msi-laptop: send out touchpad on/off key
acer-wmi: set the touchpad toggle key code to KEY_TOUCHPAD_TOGGLE
platform-driver-x86: intel_mid_thermal: fix unterminated platform_device_id table
sony-laptop: potential null dereference
sony-laptop: handle allocation failures
sony-laptop: return negative on failure in sony_nc_add()
...
* 'for-torvalds' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-stericsson:
mach-ux500: configure board for the TPS61052 regulator v2
mach-ux500: provide ab8500 init vector
mach-ux500: board support for AB8500 GPIO driver
gpio: driver for 42 AB8500 GPIO pins
Fix new irq-related kernel-doc warnings in 2.6.38:
Warning(kernel/irq/manage.c:149): No description found for parameter 'mask'
Warning(kernel/irq/manage.c:149): Excess function parameter 'cpumask' description in 'irq_set_affinity'
Warning(include/linux/irq.h:161): No description found for parameter 'state_use_accessors'
Warning(include/linux/irq.h:161): Excess struct/union/enum/typedef member 'state_use_accessor' description in 'irq_data'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <20110318093356.b939558d.randy.dunlap@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Some archs want to prevent the default affinity being set on their
chips in the reqeust_irq() path.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This is a replacment for the cell flow handler which is in the way of
cleanups. Must be selected to avoid general bloat.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We really need these flags for some of the interrupt chips. Move it
from internal state to irq_data and provide proper accessors.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Daney <ddaney@caviumnetworks.com>
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Ensure that rpc_release_resources_task() can be called twice.
NFS: Don't leak RPC clients in NFSv4 secinfo negotiation
NFS: Fix a hang in the writeback path
The define to use ({0;}) for the !CONFIG_SMP case of WARN_ON_SMP()
can be confusing. As the WARN_ON_SMP() needs to be a nop when
CONFIG_SMP is not set, including all its parameters must not be
evaluated, and that it must work as both a stand alone statement
and inside an if condition, we define it to a funky ({0;}).
A simple "0" will not work as it causes gcc to give the warning that
the statement has no effect.
As this strange definition has raised a few eyebrows from some
major kernel developers, it is wise to document why we create such
a work of art.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
