RCU no longer uses this global variable, nor does anyone else.  This
commit therefore removes this variable.  This reduces memory footprint
and also removes some atomic instructions and memory barriers from
the dyntick-idle path.
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The rcu_dereference_bh_protected() and rcu_dereference_sched_protected()
macros are synonyms for rcu_dereference_protected() and are not used
anywhere in mainline.  This commit therefore removes them.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

This patch #ifdefs TINY_RCU kthreads out of the kernel unless RCU_BOOST=y,
thus eliminating context-switch overhead if RCU priority boosting has
not been configured.
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

There was recently some controversy about the overhead of invoking RCU
callbacks.  Add TRACE_EVENT()s to obtain fine-grained timings for the
start and stop of a batch of callbacks and also for each callback invoked.
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Pull the code that waits for an RCU grace period into a single function,
which is then called by synchronize_rcu() and friends in the case of
TREE_RCU and TREE_PREEMPT_RCU, and from rcu_barrier() and friends in
the case of TINY_RCU and TINY_PREEMPT_RCU.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Take a first step towards untangling Linux kernel header files by
placing the struct rcu_head definition into include/linux/types.h
and including include/linux/types.h in include/linux/rcupdate.h
where struct rcu_head used to be defined.  The actual inclusion point
for include/linux/types.h is with the rest of the #include directives
rather than at the point where struct rcu_head used to be defined,
as suggested by Mathieu Desnoyers.

Once this is in place, then header files that need only rcu_head
can include types.h rather than rcupdate.h.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>

Long ago, using TREE_RCU with PREEMPT would result in "scheduling
while atomic" diagnostics if you blocked in an RCU read-side critical
section.  However, PREEMPT now implies TREE_PREEMPT_RCU, which defeats
this diagnostic.  This commit therefore adds a replacement diagnostic
based on PROVE_RCU.

Because rcu_lockdep_assert() and lockdep_rcu_dereference() are now being
used for things that have nothing to do with rcu_dereference(), rename
lockdep_rcu_dereference() to lockdep_rcu_suspicious() and add a third
argument that is a string indicating what is suspicious.  This third
argument is passed in from a new third argument to rcu_lockdep_assert().
Update all calls to rcu_lockdep_assert() to add an informative third
argument.

Also, add a pair of rcu_lockdep_assert() calls from within
rcu_note_context_switch(), one complaining if a context switch occurs
in an RCU-bh read-side critical section and another complaining if a
context switch occurs in an RCU-sched read-side critical section.
These are present only if the PROVE_RCU kernel parameter is enabled.

Finally, fix some checkpatch whitespace complaints in lockdep.c.

Again, you must enable PROVE_RCU to see these new diagnostics.  But you
are enabling PROVE_RCU to check out new RCU uses in any case, aren't you?
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

That flag no longer makes sense, since we don't look up automount points
as eagerly any more.  Additionally, it turns out that the NO_AUTOMOUNT
handling was buggy to begin with: it would avoid automounting even for
cases where we really *needed* to do the automount handling, and could
return ENOENT for autofs entries that hadn't been instantiated yet.

With our new non-eager automount semantics, one discussion has been
about adding a AT_AUTOMOUNT flag to vfs_fstatat (and thus the
newfstatat() and fstatat64() system calls), but it's probably not worth
it: you can always force at least directory automounting by simply
adding the final '/' to the filename, which works for *all* of the stat
family system calls, old and new.

So AT_NO_AUTOMOUNT (and thus LOOKUP_NO_AUTOMOUNT) really were just a
result of our bad default behavior.
Acked-by: NIan Kent <raven@themaw.net>
Acked-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since we've now turned around and made LOOKUP_FOLLOW *not* force an
automount, we want to add the ability to force an automount event on
lookup even if we don't happen to have one of the other flags that force
it implicitly (LOOKUP_OPEN, LOOKUP_DIRECTORY, LOOKUP_PARENT..)

Most cases will never want to use this, since you'd normally want to
delay automounting as long as possible, which usually implies
LOOKUP_OPEN (when we open a file or directory, we really cannot avoid
the automount any more).

But Trond argued sufficiently forcefully that at a minimum bind mounting
a file and quotactl will want to force the automount lookup.  Some other
cases (like nfs_follow_remote_path()) could use it too, although
LOOKUP_DIRECTORY would work there as well.

This commit just adds the flag and logic, no users yet, though.  It also
doesn't actually touch the LOOKUP_NO_AUTOMOUNT flag that is related, and
was made irrelevant by the same change that made us not follow on
LOOKUP_FOLLOW.

Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

598841ca ([S390] use gmap address
spaces for kvm guest images) changed kvm on s390 to use a separate
address space for kvm guests. We can now put KVM guests anywhere
in the user address mode with a size up to 8PB - as long as the
memory is 1MB-aligned. This change was done without KVM extension
capability bit.
The change was added after 3.0, but we still have a chance to add
a feature bit before 3.1 (keeping the releases in a sane state).
We use number 71 to avoid collisions with other pending kvm patches
as requested by Alexander Graf.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NAvi Kivity <avi@redhat.com>
Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>

dev_forward_skb loops an skb back into host networking
stack which might hang on the memory indefinitely.
In particular, this can happen in macvtap in bridged mode.
Copy the userspace fragments to avoid blocking the
sender in that case.

As this patch makes skb_copy_ubufs extern now,
I also added some documentation and made it clear
the SKBTX_DEV_ZEROCOPY flag automatically instead
of doing it in all callers. This can be made into a separate
patch if people feel it's worth it.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

"Possible SYN flooding on port xxxx " messages can fill logs on servers.

Change logic to log the message only once per listener, and add two new
SNMP counters to track :

TCPReqQFullDoCookies : number of times a SYNCOOKIE was replied to client

TCPReqQFullDrop : number of times a SYN request was dropped because
syncookies were not enabled.

Based on a prior patch from Tom Herbert, and suggestions from David.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Tom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Building a kernel with hotplug disabled results in a link failure:

  `bgpio_remove' referenced in section `___ksymtab_gpl+bgpio_remove' of drivers/built-in.o: defined in discarded section `.devexit.text' of drivers/built-in.o

This is because of bgpio_remove() is exported.  It is illegal to export
symbols which are discarded either at link time or as part of an
init/exit section.

Fix this by dropping the __devexit attributation from bgpio_remove().
Also drop the __devinit attributation from bgpio_init().
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Revert the post-3.0 commit 82f9d486 ("memcg: add
memory.vmscan_stat").

The implementation of per-memcg reclaim statistics violates how memcg
hierarchies usually behave: hierarchically.

The reclaim statistics are accounted to child memcgs and the parent
hitting the limit, but not to hierarchy levels in between.  Usually,
hierarchical statistics are perfectly recursive, with each level
representing the sum of itself and all its children.

Since this exports statistics to userspace, this may lead to confusion
and problems with changing things after the release, so revert it now,
we can try again later.
Signed-off-by: NJohannes Weiner <jweiner@redhat.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warning about internal/private data by marking it
as "private:" so that kernel-doc will ignore it.

  Warning(include/linux/regulator/consumer.h:128): No description found for parameter 'ret'
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This needs to be an out of band value for the register and on this device
registers are 16 bit so we must shift left one to the 17th bit.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@kernel.org
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

The current cgroup context switch code was incorrect leading
to bogus counts. Furthermore, as soon as there was an active
cgroup event on a CPU, the context switch cost on that CPU
would increase by a significant amount as demonstrated by a
simple ping/pong example:

 $ ./pong
 Both processes pinned to CPU1, running for 10s
 10684.51 ctxsw/s

Now start a cgroup perf stat:
 $ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 100

$ ./pong
 Both processes pinned to CPU1, running for 10s
 6674.61 ctxsw/s

That's a 37% penalty.

Note that pong is not even in the monitored cgroup.

The results shown by perf stat are bogus:
 $ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 100

 Performance counter stats for 'sleep 100':

 CPU1 <not counted> cycles   test
 CPU1 16,984,189,138 cycles  #    0.000 GHz

The second 'cycles' event should report a count @ CPU clock
(here 2.4GHz) as it is counting across all cgroups.

The patch below fixes the bogus accounting and bypasses any
cgroup switches in case the outgoing and incoming tasks are
in the same cgroup.

With this patch the same test now yields:
 $ ./pong
 Both processes pinned to CPU1, running for 10s
 10775.30 ctxsw/s

Start perf stat with cgroup:

 $ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 10

Run pong outside the cgroup:
 $ /pong
 Both processes pinned to CPU1, running for 10s
 10687.80 ctxsw/s

The penalty is now less than 2%.

And the results for perf stat are correct:

$ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 10

 Performance counter stats for 'sleep 10':

 CPU1 <not counted> cycles test #    0.000 GHz
 CPU1 23,933,981,448 cycles      #    0.000 GHz

Now perf stat reports the correct counts for
for the non cgroup event.

If we run pong inside the cgroup, then we also get the
correct counts:

$ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 10

 Performance counter stats for 'sleep 10':

 CPU1 22,297,726,205 cycles test #    0.000 GHz
 CPU1 23,933,981,448 cycles      #    0.000 GHz

      10.001457237 seconds time elapsed
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110825135803.GA4697@quadSigned-off-by: NIngo Molnar <mingo@elte.hu>

The nfsservctl system call is now gone, so we should remove all
linkage for it.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We need a callback to do some things after pwm_enable, pwm_disable
and pwm_config.
Signed-off-by: NDilan Lee <dilee@nvidia.com>
Reviewed-by: NRobert Morell <rmorell@nvidia.com>
Reviewed-by: NArun Murthy <arun.murthy@stericsson.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace/remove use of RIO v.1.2 registers/bits that are not
forward-compatible with newer versions of RapidIO specification.

RapidIO specification v.1.3 removed Write Port CSR, Doorbell CSR,
Mailbox CSR and Mailbox and Doorbell bits of the PEF CAR.

Use of removed (since RIO v.1.3) register bits affects users of
currently available 1.3 and 2.x compliant devices who may use not so
recent kernel versions.

Removing checks for unsupported bits makes corresponding routines
compatible with all versions of RapidIO specification.  Therefore,
backporting makes stable kernel versions compliant with RIO v.1.3 and
later as well.
Signed-off-by: NAlexandre 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>
Cc: Chul Kim <chul.kim@idt.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Purely in-memory filesystems do not use the inode hash as the dcache
tells us if an entry already exists.  As a result, they do not call
unlock_new_inode, and thus directory inodes do not get put into a
different lockdep class for i_sem.

We need the different lockdep classes, because the locking order for
i_mutex is different for directory inodes and regular inodes.  Directory
inodes can do "readdir()", which takes i_mutex *before* possibly taking
mm->mmap_sem (due to a page fault while copying the directory entry to
user space).

In contrast, regular inodes can be mmap'ed, which takes mm->mmap_sem
before accessing i_mutex.

The two cases can never happen for the same inode, so no real deadlock
can occur, but without the different lockdep classes, lockdep cannot
understand that.  As a result, if CONFIG_DEBUG_LOCK_ALLOC is set, this
can lead to false positives from lockdep like below:

    find/645 is trying to acquire lock:
     (&mm->mmap_sem){++++++}, at: [<ffffffff81109514>] might_fault+0x5c/0xac

    but task is already holding lock:
     (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffff81149f34>]
    vfs_readdir+0x5b/0xb4

    which lock already depends on the new lock.

    the existing dependency chain (in reverse order) is:

    -> #1 (&sb->s_type->i_mutex_key#15){+.+.+.}:
          [<ffffffff8108ac26>] lock_acquire+0xbf/0x103
          [<ffffffff814db822>] __mutex_lock_common+0x4c/0x361
          [<ffffffff814dbc46>] mutex_lock_nested+0x40/0x45
          [<ffffffff811daa87>] hugetlbfs_file_mmap+0x82/0x110
          [<ffffffff81111557>] mmap_region+0x258/0x432
          [<ffffffff811119dd>] do_mmap_pgoff+0x2ac/0x306
          [<ffffffff81111b4f>] sys_mmap_pgoff+0x118/0x16a
          [<ffffffff8100c858>] sys_mmap+0x22/0x24
          [<ffffffff814e3ec2>] system_call_fastpath+0x16/0x1b

    -> #0 (&mm->mmap_sem){++++++}:
          [<ffffffff8108a4bc>] __lock_acquire+0xa1a/0xcf7
          [<ffffffff8108ac26>] lock_acquire+0xbf/0x103
          [<ffffffff81109541>] might_fault+0x89/0xac
          [<ffffffff81149cff>] filldir+0x6f/0xc7
          [<ffffffff811586ea>] dcache_readdir+0x67/0x205
          [<ffffffff81149f54>] vfs_readdir+0x7b/0xb4
          [<ffffffff8114a073>] sys_getdents+0x7e/0xd1
          [<ffffffff814e3ec2>] system_call_fastpath+0x16/0x1b

This patch moves the directory vs file lockdep annotation into a helper
function that can be called by in-memory filesystems and has hugetlbfs
call it.
Signed-off-by: NJosh Boyer <jwboyer@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I ran into a couple of programs which broke with the new Linux 3.0
version.  Some of those were binary only.  I tried to use LD_PRELOAD to
work around it, but it was quite difficult and in one case impossible
because of a mix of 32bit and 64bit executables.

For example, all kind of management software from HP doesnt work, unless
we pretend to run a 2.6 kernel.

  $ uname -a
  Linux svivoipvnx001 3.0.0-08107-g97cd98f #1062 SMP Fri Aug 12 18:11:45 CEST 2011 i686 i686 i386 GNU/Linux

  $ hpacucli ctrl all show

  Error: No controllers detected.

  $ rpm -qf /usr/sbin/hpacucli
  hpacucli-8.75-12.0

Another notable case is that Python now reports "linux3" from
sys.platform(); which in turn can break things that were checking
sys.platform() == "linux2":

  https://bugzilla.mozilla.org/show_bug.cgi?id=664564

It seems pretty clear to me though it's a bug in the apps that are using
'==' instead of .startswith(), but this allows us to unbreak broken
programs.

This patch adds a UNAME26 personality that makes the kernel report a
2.6.40+x version number instead.  The x is the x in 3.x.

I know this is somewhat ugly, but I didn't find a better workaround, and
compatibility to existing programs is important.

Some programs also read /proc/sys/kernel/osrelease.  This can be worked
around in user space with mount --bind (and a mount namespace)

To use:

  wget ftp://ftp.kernel.org/pub/linux/kernel/people/ak/uname26/uname26.c
  gcc -o uname26 uname26.c
  ./uname26 program
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Cleaning up the code a little bit. attempt_plug_merge() traverses the plug
list anyway, we can do the request counting there, so stack size is reduced
a little bit.
The motivation here is I suspect if we should count the requests for each
queue (task could handle multiple disks in the meantime), but my test doesn't
show it's worthy doing. If somebody proves we should do it, below change
will make that more easier.
Signed-off-by: NShaohua Li <shli@kernel.org>
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

tty_operations->remove is normally called like:
queue_release_one_tty
 ->tty_shutdown
   ->tty_driver_remove_tty
     ->tty_operations->remove

However tty_shutdown() is called from queue_release_one_tty() only if
tty_operations->shutdown is NULL. But for pty, it is not.
pty_unix98_shutdown() is used there as ->shutdown.

So tty_operations->remove of pty (i.e. pty_unix98_remove()) is never
called. This results in invalid pty_count. I.e. what can be seen in
/proc/sys/kernel/pty/nr.

I see this was already reported at:
  https://lkml.org/lkml/2009/11/5/370
But it was not fixed since then.

This patch is kind of a hackish way. The problem lies in ->install. We
allocate there another tty (so-called tty->link). So ->install is
called once, but ->remove twice, for both tty and tty->link. The fix
here is to count both tty and tty->link and divide the count by 2 for
user.

And to have ->remove called, let's make tty_driver_remove_tty() global
and call that from pty_unix98_shutdown() (tty_operations->shutdown).

While at it, let's document that when ->shutdown is defined,
tty_shutdown() is not called.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NNamhyung Kim <namhyung@gmail.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Replace all occurnanced of the undocumented READ_META with READ | REQ_META
and remove the unused WRITE_META define.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Certain platform specific or Host-WiLink Interface specific actions would be
required to be taken when the chip is being enabled and after the chip is
disabled such as configuration of the mux modes for the GPIO of host connected
to the nshutdown of the chip or relinquishing UART after the chip is disabled.

Similar actions can also be taken when the chip is in deep sleep or when the
chip is awake. Performance enhancements such as configuring the host to run
faster when chip is awake and slower when chip is asleep can also be made
here.
Signed-off-by: NPavan Savoy <pavan_savoy@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Revert the pass-good area introduced in ffd1f609 ("writeback:
introduce max-pause and pass-good dirty limits") and make the max-pause
area smaller and safe.

This fixes ~30% performance regression in the ext3 data=writeback
fio_mmap_randwrite_64k/fio_mmap_randrw_64k test cases, where there are
12 JBOD disks, on each disk runs 8 concurrent tasks doing reads+writes.

Using deadline scheduler also has a regression, but not that big as CFQ,
so this suggests we have some write starvation.

The test logs show that

- the disks are sometimes under utilized

- global dirty pages sometimes rush high to the pass-good area for
  several hundred seconds, while in the mean time some bdi dirty pages
  drop to very low value (bdi_dirty << bdi_thresh).  Then suddenly the
  global dirty pages dropped under global dirty threshold and bdi_dirty
  rush very high (for example, 2 times higher than bdi_thresh). During
  which time balance_dirty_pages() is not called at all.

So the problems are

1) The random writes progress so slow that they break the assumption of
   the max-pause logic that "8 pages per 200ms is typically more than
   enough to curb heavy dirtiers".

2) The max-pause logic ignored task_bdi_thresh and thus opens the possibility
   for some bdi's to over dirty pages, leading to (bdi_dirty >> bdi_thresh)
   and then (bdi_thresh >> bdi_dirty) for others.

3) The higher max-pause/pass-good thresholds somehow leads to the bad
   swing of dirty pages.

The fix is to allow the task to slightly dirty over task_bdi_thresh, but
no way to exceed bdi_dirty and/or global dirty_thresh.

Tests show that it fixed the JBOD regression completely (both behavior
and performance), while still being able to cut down large pause times
in balance_dirty_pages() for single-disk cases.
Reported-by: NLi Shaohua <shaohua.li@intel.com>
Tested-by: NLi Shaohua <shaohua.li@intel.com>
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>

This allows the cast in lowmem_page_address (introduced as a warning
fixup to 33dd4e0e "mm: make some struct page's const") to be
removed.

Propagate const'ness to page_to_section() as well since it is required
by __page_to_pfn.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Followup to 33dd4e0e "mm: make some struct page's const" which missed the
HASHED_PAGE_VIRTUAL case.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit ae1b1539, block: reimplement
FLUSH/FUA to support merge, introduced a performance regression when
running any sort of fsyncing workload using dm-multipath and certain
storage (in our case, an HP EVA).  The test I ran was fs_mark, and it
dropped from ~800 files/sec on ext4 to ~100 files/sec.  It turns out
that dm-multipath always advertised flush+fua support, and passed
commands on down the stack, where those flags used to get stripped off.
The above commit changed that behavior:

static inline struct request *__elv_next_request(struct request_queue *q)
{
        struct request *rq;

        while (1) {
-               while (!list_empty(&q->queue_head)) {
+               if (!list_empty(&q->queue_head)) {
                        rq = list_entry_rq(q->queue_head.next);
-                       if (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) ||
-                           (rq->cmd_flags & REQ_FLUSH_SEQ))
-                               return rq;
-                       rq = blk_do_flush(q, rq);
-                       if (rq)
-                               return rq;
+                       return rq;
                }

Note that previously, a command would come in here, have
REQ_FLUSH|REQ_FUA set, and then get handed off to blk_do_flush:

struct request *blk_do_flush(struct request_queue *q, struct request *rq)
{
        unsigned int fflags = q->flush_flags; /* may change, cache it */
        bool has_flush = fflags & REQ_FLUSH, has_fua = fflags & REQ_FUA;
        bool do_preflush = has_flush && (rq->cmd_flags & REQ_FLUSH);
        bool do_postflush = has_flush && !has_fua && (rq->cmd_flags &
        REQ_FUA);
        unsigned skip = 0;
...
        if (blk_rq_sectors(rq) && !do_preflush && !do_postflush) {
                rq->cmd_flags &= ~REQ_FLUSH;
		if (!has_fua)
			rq->cmd_flags &= ~REQ_FUA;
	        return rq;
	}

So, the flush machinery was bypassed in such cases (q->flush_flags == 0
&& rq->cmd_flags & (REQ_FLUSH|REQ_FUA)).

Now, however, we don't get into the flush machinery at all.  Instead,
__elv_next_request just hands a request with flush and fua bits set to
the scsi_request_fn, even if the underlying request_queue does not
support flush or fua.

The agreed upon approach is to fix the flush machinery to allow
stacking.  While this isn't used in practice (since there is only one
request-based dm target, and that target will now reflect the flush
flags of the underlying device), it does future-proof the solution, and
make it function as designed.

In order to make this work, I had to add a field to the struct request,
inside the flush structure (to store the original req->end_io).  Shaohua
had suggested overloading the union with rb_node and completion_data,
but the completion data is used by device mapper and can also be used by
other drivers.  So, I didn't see a way around the additional field.

I tested this patch on an HP EVA with both ext4 and xfs, and it recovers
the lost performance.  Comments and other testers, as always, are
appreciated.

Cheers,
Jeff
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Function genpd_queue_power_off_work() is not defined for
CONFIG_PM_RUNTIME, so pm_genpd_poweroff_unused() causes a build
error to happen in that case.  Fix the problem by making
pm_genpd_poweroff_unused() depend on CONFIG_PM_RUNTIME too.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

"mmc: dw_mmc: Fix DDR mode support" removed the last user.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NChris Ball <cjb@laptop.org>

The patch http://lkml.org/lkml/2003/7/13/226 introduced an RLIMIT_NPROC
check in set_user() to check for NPROC exceeding via setuid() and
similar functions.

Before the check there was a possibility to greatly exceed the allowed
number of processes by an unprivileged user if the program relied on
rlimit only.  But the check created new security threat: many poorly
written programs simply don't check setuid() return code and believe it
cannot fail if executed with root privileges.  So, the check is removed
in this patch because of too often privilege escalations related to
buggy programs.

The NPROC can still be enforced in the common code flow of daemons
spawning user processes.  Most of daemons do fork()+setuid()+execve().
The check introduced in execve() (1) enforces the same limit as in
setuid() and (2) doesn't create similar security issues.

Neil Brown suggested to track what specific process has exceeded the
limit by setting PF_NPROC_EXCEEDED process flag.  With the change only
this process would fail on execve(), and other processes' execve()
behaviour is not changed.

Solar Designer suggested to re-check whether NPROC limit is still
exceeded at the moment of execve().  If the process was sleeping for
days between set*uid() and execve(), and the NPROC counter step down
under the limit, the defered execve() failure because NPROC limit was
exceeded days ago would be unexpected.  If the limit is not exceeded
anymore, we clear the flag on successful calls to execve() and fork().

The flag is also cleared on successful calls to set_user() as the limit
was exceeded for the previous user, not the current one.

Similar check was introduced in -ow patches (without the process flag).

v3 - clear PF_NPROC_EXCEEDED on successful calls to set_user().
Reviewed-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NVasiliy Kulikov <segoon@openwall.com>
Acked-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add FLUSH/FUA support to blktrace. As FLUSH precedes WRITE and/or
FUA follows WRITE, use the same 'F' flag for both cases and
distinguish them by their (relative) position. The end results
look like (other flags might be shown also):

 - WRITE:            W
 - WRITE_FLUSH:      FW
 - WRITE_FUA:        WF
 - WRITE_FLUSH_FUA:  FWF

Note that we reuse TC_BARRIER due to lack of bit space of act_mask
so that the older versions of blktrace tools will report flush
requests as barriers from now on.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

REQ_SECURE, REQ_FLUSH and REQ_FUA may all be set on a bio as well as
on a request, so relocate them to the shared part of the enum.
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Thomas earlier submitted a fix to limit the RTC PIE freq, but
picked 5000Hz out of the air. Willy noticed that we should
instead use the 8192Hz max from the rtc man documentation.

Cc: Willy Tarreau <w@1wt.eu>
Cc: stable@kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

The patch adds empty function of_get_property for non-dt build, so that
drivers migrating to dt can save some '#ifdef CONFIG_OF'.

This also fixes the current Tegra compile problem in linux-next.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

In commit 2efaca92 ("mm/futex: fix futex writes on archs with SW
tracking of dirty & young") we forgot about MMU=n.  This patch fixes
that.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NDavid Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/1311761831.24752.413.camel@twinsSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>