Neither host_irq nor the guest_msi struct are used anymore today.
Tag the former, drop the latter to avoid confusion.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Under heavy memory and filesystem load, users observe the assertion
mapping->nrpages == 0 in end_writeback() trigger.  This can be caused by
page reclaim reclaiming the last page from a mapping in the following
race:

	CPU0				CPU1
  ...
  shrink_page_list()
    __remove_mapping()
      __delete_from_page_cache()
        radix_tree_delete()
					evict_inode()
					  truncate_inode_pages()
					    truncate_inode_pages_range()
					      pagevec_lookup() - finds nothing
					  end_writeback()
					    mapping->nrpages != 0 -> BUG
        page->mapping = NULL
        mapping->nrpages--

Fix the problem by doing a reliable check of mapping->nrpages under
mapping->tree_lock in end_writeback().

Analyzed by Jay <jinshan.xiong@whamcloud.com>, lost in LKML, and dug out
by Miklos Szeredi <mszeredi@suse.de>.

Cc: Jay <jinshan.xiong@whamcloud.com>
Cc: Miklos Szeredi <mszeredi@suse.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is required for tilegx to be able to use the compat unistd.h header
where compat_sys_sendmmsg() is now mentioned.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Although it is used (by i915) on nothing but tmpfs, read_cache_page_gfp()
is unsuited to tmpfs, because it inserts a page into pagecache before
calling the filesystem's ->readpage: tmpfs may have pages in swapcache
which only it knows how to locate and switch to filecache.

At present tmpfs provides a ->readpage method, and copes with this by
copying pages; but soon we can simplify it by removing its ->readpage.
Provide shmem_read_mapping_page_gfp() now, ready for that transition,

Export shmem_read_mapping_page_gfp() and add it to list in shmem_fs.h,
with shmem_read_mapping_page() inline for the common mapping_gfp case.

(shmem_read_mapping_page_gfp or shmem_read_cache_page_gfp? Generally the
read_mapping_page functions use the mapping's ->readpage, and the
read_cache_page functions use the supplied filler, so I think
read_cache_page_gfp was slightly misnamed.)
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

2.6.35's new truncate convention gave tmpfs the opportunity to control
its file truncation, no longer enforced from outside by vmtruncate().
We shall want to build upon that, to handle pagecache and swap together.

Slightly redefine the ->truncate_range interface: let it now be called
between the unmap_mapping_range()s, with the filesystem responsible for
doing the truncate_inode_pages_range() from it - just as the filesystem
is nowadays responsible for doing that from its ->setattr.

Let's rename shmem_notify_change() to shmem_setattr().  Instead of
calling the generic truncate_setsize(), bring that code in so we can
call shmem_truncate_range() - which will later be updated to perform its
own variant of truncate_inode_pages_range().

Remove the punch_hole unmap_mapping_range() from shmem_truncate_range():
now that the COW's unmap_mapping_range() comes after ->truncate_range,
there is no need to call it a third time.

Export shmem_truncate_range() and add it to the list in shmem_fs.h, so
that i915_gem_object_truncate() can call it explicitly in future; get
this patch in first, then update drm/i915 once this is available (until
then, i915 will just be doing the truncate_inode_pages() twice).

Though introduced five years ago, no other filesystem is implementing
->truncate_range, and its only other user is madvise(,,MADV_REMOVE): we
expect to convert it to fallocate(,FALLOC_FL_PUNCH_HOLE,,) shortly,
whereupon ->truncate_range can be removed from inode_operations -
shmem_truncate_range() will help i915 across that transition too.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Before adding any more global entry points into shmem.c, gather such
prototypes into shmem_fs.h.  Remove mm's own declarations from swap.h,
but for now leave the ones in mm.h: because shmem_file_setup() and
shmem_zero_setup() are called from various places, and we should not
force other subsystems to update immediately.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix 'make htmldocs' warnings:

  Warning(/include/linux/hrtimer.h:153): No description found for parameter 'clockid'
  Warning(/include/linux/device.h:604): Excess struct/union/enum/typedef member 'of_match' description in 'device'
  Warning(/include/net/sock.h:349): Excess struct/union/enum/typedef member 'sk_rmem_alloc' description in 'sock'
Signed-off-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

commit 21a3c964 uses node_start/end_pfn(nid) for detection start/end
of nodes. But, it's not defined in linux/mmzone.h but defined in
/arch/???/include/mmzone.h which is included only under
CONFIG_NEED_MULTIPLE_NODES=y.

Then, we see
  mm/page_cgroup.c: In function 'page_cgroup_init':
  mm/page_cgroup.c:308: error: implicit declaration of function 'node_start_pfn'
  mm/page_cgroup.c:309: error: implicit declaration of function 'node_end_pfn'

So, fixiing page_cgroup.c is an idea...

But node_start_pfn()/node_end_pfn() is a very generic macro and
should be implemented in the same manner for all archs.
(m32r has different implementation...)

This patch removes definitions of node_start/end_pfn() in each archs
and defines a unified one in linux/mmzone.h. It's not under
CONFIG_NEED_MULTIPLE_NODES, now.

A result of macro expansion is here (mm/page_cgroup.c)

for !NUMA
 start_pfn = ((&contig_page_data)->node_start_pfn);
  end_pfn = ({ pg_data_t *__pgdat = (&contig_page_data); __pgdat->node_start_pfn + __pgdat->node_spanned_pages;});

for NUMA (x86-64)
  start_pfn = ((node_data[nid])->node_start_pfn);
  end_pfn = ({ pg_data_t *__pgdat = (node_data[nid]); __pgdat->node_start_pfn + __pgdat->node_spanned_pages;});

Changelog:
 - fixed to avoid using "nid" twice in node_end_pfn() macro.
Reported-and-acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Reported-and-tested-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NMel Gorman <mgorman@suse.de>
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The Freescale DIU framebuffer driver defines two constants, MIN_PIX_CLK and
MAX_PIX_CLK, that are supposed to represent the lower and upper limits of
the pixel clock.  These values, however, are true only for one platform
clock rate (533MHz) and only for the MPC8610.  So the actual range for
the pixel clock is chip-specific, which means the current values are almost
always wrong.  The chance of an out-of-range pixel clock being used are also
remote.

Rather than try to detect an out-of-range clock in the DIU driver, we depend
on the board-specific pixel clock function (e.g. p1022ds_set_pixel_clock)
to clamp the pixel clock to a supported value.
Signed-off-by: NTimur Tabi <timur@freescale.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The PM core doesn't handle suspend failures correctly when it comes to
asynchronously suspended devices.  These devices are moved onto the
dpm_suspended_list as soon as the corresponding async thread is
started up, and they remain on the list even if they fail to suspend
or the sleep transition is cancelled before they get suspended.  As a
result, when the PM core unwinds the transition, it tries to resume
the devices even though they were never suspended.

This patch (as1474) fixes the problem by adding a new "is_suspended"
flag to dev_pm_info.  Devices are resumed only if the flag is set.

[rjw:
 * Moved the dev->power.is_suspended check into device_resume(),
   because we need to complete dev->power.completion and clear
   dev->power.is_prepared too for devices whose
   dev->power.is_suspended flags are unset.
 * Fixed __device_suspend() to avoid setting dev->power.is_suspended
   if async_error is different from zero.]
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org

This patch (as1473) renames the "in_suspend" field in struct
dev_pm_info to "is_prepared", in preparation for an upcoming change.
The new name is more descriptive of what the field really means.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org

Commit 13e12d14 ("vfs: reorganize 'struct inode' layout a bit")
moved things around a bit changed i_state to be unsigned int instead of
unsigned long.  That was to help structure layout for the 64-bit case,
and shrink 'struct inode' a bit (admittedly that only happened when
spinlock debugging was on and i_flags didn't pack with i_lock).

However, Meelis Roos reports that this results in unaligned exceptions
on sprc, and it turns out that the bit-locking primitives that we use
for the I_NEW bit want to use the bitops.  Which want 'unsigned long',
not 'unsigned int'.

We really should fix the bit locking code to not have that kind of
requirement, but that's a much bigger change.  So for now, revert that
field back to 'unsigned long' (but keep the other re-ordering changes
from the commit that caused this).

Andi points out that we have played games with this in 'struct page', so
it's solvable with other hacks too, but since right now the struct inode
size advantage only happens with some rare config options, it's not
worth fighting.

It _would_ be worth fixing the bitlocking code, though.  Especially
since there is no type safety in the bitlocking code (this never caused
any warnings, and worked fine on x86-64, because the bitlocks take a
'void *' and x86-64 doesn't care that deeply about alignment).  So it's
currently a very easy problem to trigger by mistake and never notice.
Reported-by: NMeelis Roos <mroos@linux.ee>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Otherwise we end up overflowing the rpc buffer size on the receive end.
Signed-off-by: NBenny Halevy <benny@tonian.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

inode_permission() calls devcgroup_inode_permission() and almost all such
calls are _not_ for device nodes; let's at least keep the common path
straight...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add REQ_SECURE flag to REQ_COMMON_MASK so that
init_request_from_bio() can pass it to @req->cmd_flags.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: stable@kernel.org # 2.6.36 and newer
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Signed-off-by: NManoj Iyer <manoj.iyer@canonical.com>
Cc: <stable@kernel.org>
Signed-off-by: NChris Ball <cjb@laptop.org>

According to the data sheet for G4, AP4 and AG5 KEYSC MODE_6 is 8x8 keys.
Bump up MAXKEYS to 64 too.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Reviewed-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

____call_usermodehelper() now erases any credentials set by the
subprocess_inf::init() function.  The problem is that commit
17f60a7d ("capabilites: allow the application of capability limits
to usermode helpers") creates and commits new credentials with
prepare_kernel_cred() after the call to the init() function.  This wipes
all keyrings after umh_keys_init() is called.

The best way to deal with this is to put the init() call just prior to
the commit_creds() call, and pass the cred pointer to init().  That
means that umh_keys_init() and suchlike can modify the credentials
_before_ they are published and potentially in use by the rest of the
system.

This prevents request_key() from working as it is prevented from passing
the session keyring it set up with the authorisation token to
/sbin/request-key, and so the latter can't assume the authority to
instantiate the key.  This causes the in-kernel DNS resolver to fail
with ENOKEY unconditionally.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NEric Paris <eparis@redhat.com>
Tested-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a problem that kdump(2nd kernel) sometimes hangs up due
to a pending IPI from 1st kernel. Kernel panic occurs because IPI
comes before call_single_queue is initialized.

To fix the crash, rename init_call_single_data() to call_function_init()
and call it in start_kernel() so that call_single_queue can be
initialized before enabling interrupts.

The details of the crash are:

 (1) 2nd kernel boots up

 (2) A pending IPI from 1st kernel comes when irqs are first enabled
     in start_kernel().

 (3) Kernel tries to handle the interrupt, but call_single_queue
     is not initialized yet at this point. As a result, in the
     generic_smp_call_function_single_interrupt(), NULL pointer
     dereference occurs when list_replace_init() tries to access
     &q->list.next.

Therefore this patch changes the name of init_call_single_data()
to call_function_init() and calls it before local_irq_enable()
in start_kernel().
Signed-off-by: NTakao Indoh <indou.takao@jp.fujitsu.com>
Reviewed-by: NWANG Cong <xiyou.wangcong@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Milton Miller <miltonm@bga.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: kexec@lists.infradead.org
Link: http://lkml.kernel.org/r/D6CBEE2F420741indou.takao@jp.fujitsu.comSigned-off-by: NIngo Molnar <mingo@elte.hu>

This workaround aims to break the deadlock situation
which raises during continuous transfer of data for long
duration over uart with hardware flow control. It is
observed that CTS interrupt cannot be cleared in uart
interrupt register (ICR). Hence further transfer over
uart gets blocked.

It is seen that during such deadlock condition ICR
don't get cleared even on multiple write. This leads
pass_counter to decrease and finally reach zero. This
can be taken as trigger point to run this UART_BT_WA.

Workaround backups the register configuration, does soft
reset of UART using BIT-0 of PRCC_K_SOFTRST_SET/CLEAR
registers and restores the registers.

This patch also provides support for uart init and exit
function calls if present.
Signed-off-by: NShreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The clocksource watchdog code is interruptible and it has been
observed that this can trigger false positives which disable the TSC.

The reason is that an interrupt storm or a long running interrupt
handler between the read of the watchdog source and the read of the
TSC brings the two far enough apart that the delta is larger than the
unstable treshold. Move both reads into a short interrupt disabled
region to avoid that.
Reported-and-tested-by: NVernon Mauery <vernux@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org

Make GPIOF_ defined values available even when GPIOLIB nor GENERIC_GPIO
is enabled by moving them to <linux/gpio.h>.

Fixes these build errors in linux-next:
sound/soc/codecs/ak4641.c:524: error: 'GPIOF_OUT_INIT_LOW' undeclared (first use in this function)
sound/soc/codecs/wm8915.c:2921: error: 'GPIOF_OUT_INIT_LOW' undeclared (first use in this function)
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

The "hostname" tool falls back to setting the hostname to "localhost" if
/etc/hostname does not exist.  Distribution init scripts have the same
fallback.  However, if userspace never calls sethostname, such as when
booting with init=/bin/sh, or otherwise booting a minimal system without
the usual init scripts, the default hostname of "(none)" remains,
unhelpfully appearing in various places such as prompts ("root@(none):~#")
and logs.  Furthermore, "(none)" doesn't typically resolve to anything
useful.

Make the default hostname configurable.  This removes the need for the
standard fallback, provides a useful default for systems that never call
sethostname, and makes minimal systems that much more useful with less
configuration.  Distributions could choose to use "localhost" here to
avoid the fallback, while embedded systems may wish to use a specific
target hostname.
Signed-off-by: NJosh Triplett <josh@joshtriplett.org>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: NDavid Miller <davem@davemloft.net>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Kel Modderman <kel@otaku42.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

BUILD_BUG_ON_ZERO and BUILD_BUG_ON_NULL must return values, even in the
CHECKER case otherwise various users of it become syntactically invalid.
Signed-off-by: NDr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Recently, Robert Mueller reported (http://lkml.org/lkml/2010/9/12/236)
that zone_reclaim_mode doesn't work properly on his new NUMA server (Dual
Xeon E5520 + Intel S5520UR MB).  He is using Cyrus IMAPd and it's built on
a very traditional single-process model.

  * a master process which reads config files and manages the other
    process
  * multiple imapd processes, one per connection
  * multiple pop3d processes, one per connection
  * multiple lmtpd processes, one per connection
  * periodical "cleanup" processes.

There are thousands of independent processes.  The problem is, recent
Intel motherboard turn on zone_reclaim_mode by default and traditional
prefork model software don't work well on it.  Unfortunatelly, such models
are still typical even in the 21st century.  We can't ignore them.

This patch raises the zone_reclaim_mode threshold to 30.  30 doesn't have
any specific meaning.  but 20 means that one-hop QPI/Hypertransport and
such relatively cheap 2-4 socket machine are often used for traditional
servers as above.  The intention is that these machines don't use
zone_reclaim_mode.

Note: ia64 and Power have arch specific RECLAIM_DISTANCE definitions.
This patch doesn't change such high-end NUMA machine behavior.

Dave Hansen said:

: I know specifically of pieces of x86 hardware that set the information
: in the BIOS to '21' *specifically* so they'll get the zone_reclaim_mode
: behavior which that implies.
:
: They've done performance testing and run very large and scary benchmarks
: to make sure that they _want_ this turned on.  What this means for them
: is that they'll probably be de-optimized, at least on newer versions of
: the kernel.
:
: If you want to do this for particular systems, maybe _that_'s what we
: should do.  Have a list of specific configurations that need the
: defaults overridden either because they're buggy, or they have an
: unusual hardware configuration not really reflected in the distance
: table.

And later said:

: The original change in the hardware tables was for the benefit of a
: benchmark.  Said benchmark isn't going to get run on mainline until the
: next batch of enterprise distros drops, at which point the hardware where
: this was done will be irrelevant for the benchmark.  I'm sure any new
: hardware will just set this distance to another yet arbitrary value to
: make the kernel do what it wants.  :)
:
: Also, when the hardware got _set_ to this initially, I complained.  So, I
: guess I'm getting my way now, with this patch.  I'm cool with it.
Reported-by: NRobert Mueller <robm@fastmail.fm>
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Acked-by: NDave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix <linux/kmsg_dump.h> when CONFIG_PRINTK is not enabled:

  include/linux/kmsg_dump.h:56: error: 'EINVAL' undeclared (first use in this function)
  include/linux/kmsg_dump.h:61: error: 'EINVAL' undeclared (first use in this function)

Looks like commit 595dd3d8 ("kmsg_dump: fix build for
CONFIG_PRINTK=n") uses EINVAL without having the needed header file(s),
but I'm sure that I build tested that patch also.  oh well.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, memcg reclaim can disable swap token even if the swap token mm
doesn't belong in its memory cgroup.  It's slightly risky.  If an admin
creates very small mem-cgroup and silly guy runs contentious heavy memory
pressure workload, every tasks are going to lose swap token and then
system may become unresponsive.  That's bad.

This patch adds 'memcg' parameter into disable_swap_token().  and if the
parameter doesn't match swap token, VM doesn't disable it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel<riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We don't support header padding yet so better off ditching it
Reported-by: NSid Moore <learnmost@gmail.com>
Signed-off-by: NBenny Halevy <benny@tonian.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the NLM daemon is killed on the NFS server, we can currently end up
hanging forever on an 'unlock' request, instead of aborting. Basically,
if the rpcbind request fails, or the server keeps returning garbage, we
really want to quit instead of retrying.
Tested-by: NVasily Averin <vvs@sw.ru>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

Commit a26ac245(rcu: move TREE_RCU from softirq to kthread)
introduced performance regression. In an AIM7 test, this commit degraded
performance by about 40%.

The commit runs rcu callbacks in a kthread instead of softirq. We observed
high rate of context switch which is caused by this. Out test system has
64 CPUs and HZ is 1000, so we saw more than 64k context switch per second
which is caused by RCU's per-CPU kthread.  A trace showed that most of
the time the RCU per-CPU kthread doesn't actually handle any callbacks,
but instead just does a very small amount of work handling grace periods.
This means that RCU's per-CPU kthreads are making the scheduler do quite
a bit of work in order to allow a very small amount of RCU-related
processing to be done.

Alex Shi's analysis determined that this slowdown is due to lock
contention within the scheduler.  Unfortunately, as Peter Zijlstra points
out, the scheduler's real-time semantics require global action, which
means that this contention is inherent in real-time scheduling.  (Yes,
perhaps someone will come up with a workaround -- otherwise, -rt is not
going to do well on large SMP systems -- but this patch will work around
this issue in the meantime.  And "the meantime" might well be forever.)

This patch therefore re-introduces softirq processing to RCU, but only
for core RCU work.  RCU callbacks are still executed in kthread context,
so that only a small amount of RCU work runs in softirq context in the
common case.  This should minimize ksoftirqd execution, allowing us to
skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels.
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Tested-by: N"Alex,Shi" <alex.shi@intel.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

jbd2_journal_remove_journal_head() can oops when trying to access
journal_head returned by bh2jh(). This is caused for example by the
following race:

	TASK1					TASK2
  jbd2_journal_commit_transaction()
    ...
    processing t_forget list
      __jbd2_journal_refile_buffer(jh);
      if (!jh->b_transaction) {
        jbd_unlock_bh_state(bh);
					jbd2_journal_try_to_free_buffers()
					  jbd2_journal_grab_journal_head(bh)
					  jbd_lock_bh_state(bh)
					  __journal_try_to_free_buffer()
					  jbd2_journal_put_journal_head(jh)
        jbd2_journal_remove_journal_head(bh);

jbd2_journal_put_journal_head() in TASK2 sees that b_jcount == 0 and
buffer is not part of any transaction and thus frees journal_head
before TASK1 gets to doing so. Note that even buffer_head can be
released by try_to_free_buffers() after
jbd2_journal_put_journal_head() which adds even larger opportunity for
oops (but I didn't see this happen in reality).

Fix the problem by making transactions hold their own journal_head
reference (in b_jcount). That way we don't have to remove journal_head
explicitely via jbd2_journal_remove_journal_head() and instead just
remove journal_head when b_jcount drops to zero. The result of this is
that [__]jbd2_journal_refile_buffer(),
[__]jbd2_journal_unfile_buffer(), and
__jdb2_journal_remove_checkpoint() can free journal_head which needs
modification of a few callers. Also we have to be careful because once
journal_head is removed, buffer_head might be freed as well. So we
have to get our own buffer_head reference where it matters.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Use the compiler to verify format strings and arguments.

Fix fallout.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

	* new refcount in struct net, controlling actual freeing of the memory
	* new method in kobj_ns_type_operations (->drop_ns())
	* ->current_ns() semantics change - it's supposed to be followed by
corresponding ->drop_ns().  For struct net in case of CONFIG_NET_NS it bumps
the new refcount; net_drop_ns() decrements it and calls net_free() if the
last reference has been dropped.  Method renamed to ->grab_current_ns().
	* old net_free() callers call net_drop_ns() instead.
	* sysfs_exit_ns() is gone, along with a large part of callchain
leading to it; now that the references stored in ->ns[...] stay valid we
do not need to hunt them down and replace them with NULL.  That fixes
problems in sysfs_lookup() and sysfs_readdir(), along with getting rid
of sb->s_instances abuse.

	Note that struct net *shutdown* logics has not changed - net_cleanup()
is called exactly when it used to be called.  The only thing postponed by
having a sysfs instance refering to that struct net is actual freeing of
memory occupied by struct net.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Testing of VLAN_FLAG_REORDER_HDR does not belong in vlan_untag
but rather in vlan_do_receive.  Otherwise the vlan header
will not be properly put on the packet in the case of
vlan header accelleration.

As we remove the check from vlan_check_reorder_header
rename it vlan_reorder_header to keep the naming clean.

Fix up the skb->pkt_type early so we don't look at the packet
after adding the vlan tag, which guarantees we don't goof
and look at the wrong field.

Use a simple if statement instead of a complicated switch
statement to decided that we need to increment rx_stats
for a multicast packet.

Hopefully at somepoint we will just declare the case where
VLAN_FLAG_REORDER_HDR is cleared as unsupported and remove
the code.  Until then this keeps it working correctly.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Acked-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It uses cpu_relax(), and so needs <asm/processor.h>

Without this patch, I see:

   CC      arch/mn10300/kernel/asm-offsets.s
  In file included from include/linux/time.h:8,
                   from include/linux/timex.h:56,
                   from include/linux/sched.h:57,
                   from arch/mn10300/kernel/asm-offsets.c:7:
  include/linux/seqlock.h: In function 'read_seqbegin':
  include/linux/seqlock.h:91: error: implicit declaration of function 'cpu_relax'

whilst building asb2364_defconfig on MN10300.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/basic_mmio_gpio.h uses a spinlock_t without including any
of the spinlock headers resulting in this compiler warning.

include/linux/basic_mmio_gpio.h:51:2: error: expected specifier-qualifier-list before 'spinlock_t'

Explicitly include linux/spinlock_types.h to fix it.
Signed-off-by: NJamie Iles <jamie@jamieiles.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

Signed-off-by: NYegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This tries to make the 'struct inode' accesses denser in the data cache
by moving a commonly accessed field (i_security) closer to other fields
that are accessed often.

It also makes 'i_state' just an 'unsigned int' rather than 'unsigned
long', since we only use a few bits of that field, and moves it next to
the existing 'i_flags' so that we potentially get better structure
layout (although depending on config options, i_flags may already have
packed in the same word as i_lock, so this improves packing only for the
case of spinlock debugging)

Out 'struct inode' is still way too big, and we should probably move
some other fields around too (the acl fields in particular) for better
data cache access density.  Other fields (like the inode hash) are
likely to be entirely irrelevant under most loads.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The CN_NETLINK_USERS must be set to the highest valid index +1.
Thanks to Evgeniy for pointing this out.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Acked-by: NEvgeniy Polyakov <zbr@ioremap.net>
Cc: stable <stable@kernel.org> [.39]
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>