Sometimes we only want to write pages from a specific super_block,
so allow that to be passed in.

This fixes a problem with commit 56a131dc
causing writeback on all super_blocks on a bdi, where we only really
want to sync a specific sb from writeback_inodes_sb().
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Nobody uses acpi_device_uid(), so this patch removes it.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Every acpi_device has at least one ID (if there's no _HID or _CID, we
give it a synthetic or default ID).  So there's no longer a need to
check whether an ID exists; we can just use it.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

We now keep a single list of IDs that includes both the _HID and any
_CIDs.  We no longer need to keep track of whether the device has a _CID.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

There's no need to treat _HID and _CID differently.  Keeping them in
a single list makes code that uses the IDs a little simpler because it
can just traverse the list rather than checking "do we have a HID?",
"do we have any CIDs?"
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Reviewed-by: NAlex Chiang <achiang@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Add acpi_bus_get_status_handle() so we can get the status of a namespace
object before building a struct acpi_device.

This removes a use of "device->flags.dynamic_status", a cached indicator of
whether _STA exists.  It seems simpler and more reliable to just evaluate
_STA and catch AE_NOT_FOUND errors.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

We can identify the root of the ACPI device tree by the fact that it
has no parent.  This is simpler than passing around ACPI_BUS_TYPE_SYSTEM
and will help remove special treatment of the device tree root.

Currently, we add the root by hand with ACPI_BUS_TYPE_SYSTEM.  If we
traverse the tree treating the root as just another device and use
acpi_get_type(), the root shows up as ACPI_TYPE_DEVICE.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Most uses of the ACPI bus device_type (ACPI_BUS_TYPE_DEVICE,
ACPI_BUS_TYPE_POWER, etc) are during device initialization, but
we do need it later for notify handler installation, since that
is different for fixed hardware devices vs. namespace devices.

This patch saves the device_type in the acpi_device structure,
so we can check that rather than comparing against the _HID string.
Signed-off-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

The NOMMU fallback for is_vmalloc_or_module_addr() should be static inline,
not just static, in linux/mm.h.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The old RW_DATA_SECTION had INIT_TASK_DATA (which was
more-than-PAGE_SIZE-aligned), followed by a bunch of small alignment
stuff, followed by more PAGE_SIZE-aligned stuff, so you wasted memory
in the middle of .data re-aligning back up to PAGE_SIZE.

This patch sorts the sections by alignment requirements, which should
pack them essentially optimally.
Signed-off-by: NTim Abbott <tabbott@ksplice.com>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Why macros are always wrong:

  mm/mmap.c: In function 'do_mmap_pgoff':
  mm/mmap.c:953: warning: unused variable 'user'

also, move a couple of struct forward-decls outside `#ifdef
CONFIG_HUGETLB_PAGE' - it's pointless and frequently harmful to make these
conditional (eg, this patch needed `struct user_struct').

Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: Eric B Munson <ebmunson@us.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Similar to commit d136f1bd,
there's a bug when unregistering a generic netlink family,
which is caught by the might_sleep() added in that commit:

    BUG: sleeping function called from invalid context at net/netlink/af_netlink.c:183
    in_atomic(): 1, irqs_disabled(): 0, pid: 1510, name: rmmod
    2 locks held by rmmod/1510:
     #0:  (genl_mutex){+.+.+.}, at: [<ffffffff8138283b>] genl_unregister_family+0x2b/0x130
     #1:  (rcu_read_lock){.+.+..}, at: [<ffffffff8138270c>] __genl_unregister_mc_group+0x1c/0x120
    Pid: 1510, comm: rmmod Not tainted 2.6.31-wl #444
    Call Trace:
     [<ffffffff81044ff9>] __might_sleep+0x119/0x150
     [<ffffffff81380501>] netlink_table_grab+0x21/0x100
     [<ffffffff813813a3>] netlink_clear_multicast_users+0x23/0x60
     [<ffffffff81382761>] __genl_unregister_mc_group+0x71/0x120
     [<ffffffff81382866>] genl_unregister_family+0x56/0x130
     [<ffffffffa0007d85>] nl80211_exit+0x15/0x20 [cfg80211]
     [<ffffffffa000005a>] cfg80211_exit+0x1a/0x40 [cfg80211]

Fix in the same way by grabbing the netlink table lock
before doing rcu_read_lock().
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It seems recursion field from "struct ip_tunnel" is not anymore needed.
recursion prevention is done at the upper level (in dev_queue_xmit()),
since we use HARD_TX_LOCK protection for tunnels.

This avoids a cache line ping pong on "struct ip_tunnel" : This structure
should be now mostly read on xmit and receive paths.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If we ever implement this, then we can stop returning an error.
Signed-off-by: NRémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the longest time now we've been using multiple MODULE_AUTHOR()
statements when a module has more than one author, but the comment here
disagrees.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Also remove all parts of the string table (referenced by the symbol
table) that are not needed for kallsyms use (i.e. which were only
referenced by symbols discarded by the previous patch, or not
referenced at all for whatever reason).
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Discard all symbols not interesting for kallsyms use: absolute,
section, and in the common case (!KALLSYMS_ALL) data ones.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Because the binfmt is not different between threads in the same process,
it can be moved from task_struct to mm_struct.  And binfmt moudle is
handled per mm_struct instead of task_struct.
Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When unaligned accesses are required for uncompressing a kernel (such as
for LZO decompression on ARM in a patch that follows), including
<linux/kernel.h> causes issues as it brings in a lot of things that are
not available in the decompression environment.

linux/kernel.h brings at least:
extern int console_printk[];
extern const char hex_asc[];
which causes errors at link-time as they are not available when
compiling the pre-boot environement. There are also a few others:

  arch/arm/boot/compressed/misc.o: In function `valid_user_regs':
   arch/arm/include/asm/ptrace.h:158: undefined reference to `elf_hwcap'
  arch/arm/boot/compressed/misc.o: In function `console_silent':
   include/linux/kernel.h:292: undefined reference to `console_printk'
  arch/arm/boot/compressed/misc.o: In function `console_verbose':
   include/linux/kernel.h:297: undefined reference to `console_printk'
  arch/arm/boot/compressed/misc.o: In function `pack_hex_byte':
   include/linux/kernel.h:360: undefined reference to `hex_asc'
  arch/arm/boot/compressed/misc.o: In function `hweight_long':
   include/linux/bitops.h:45: undefined reference to `hweight32'
  arch/arm/boot/compressed/misc.o: In function `__cmpxchg_local_generic':
   include/asm-generic/cmpxchg-local.h:21: undefined reference to `wrong_size_cmpxchg'
   include/asm-generic/cmpxchg-local.h:42: undefined reference to `wrong_size_cmpxchg'
  arch/arm/boot/compressed/misc.o: In function `__xchg':
   arch/arm/include/asm/system.h:309: undefined reference to `__bad_xchg'

However, those files apparently use nothing from <linux/kernel.h>, all
they need is the declaration of types such as u32 or u64, so
<linux/types.h> should be enough
Signed-off-by: NAlbin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

->ioctx_lock and ->ioctx_list are used only under CONFIG_AIO.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The forward decls for some kernel types are only needed by the code behind
__KERNEL__, so don't bleed these types to userspace.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's unused.

It isn't needed -- read or write flag is already passed and sysctl
shouldn't care about the rest.

It _was_ used in two places at arch/frv for some reason.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__fatal_signal_pending inlines to one instruction on x86, probably two
instructions on other machines.  It takes two longer x86 instructions just
to call it and test its return value, not to mention the function itself.

On my random x86_64 config, this saved 70 bytes of text (59 of those being
__fatal_signal_pending itself).
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In order to direct the SIGIO signal to a particular thread of a
multi-threaded application we cannot, like suggested by the manpage, put a
TID into the regular fcntl(F_SETOWN) call.  It will still be send to the
whole process of which that thread is part.

Since people do want to properly direct SIGIO we introduce F_SETOWN_EX.

The need to direct SIGIO comes from self-monitoring profiling such as with
perf-counters.  Perf-counters uses SIGIO to notify that new sample data is
available.  If the signal is delivered to the same task that generated the
new sample it can augment that data by inspecting the task's user-space
state right after it returns from the kernel.  This is esp.  convenient
for interpreted or virtual machine driven environments.

Both F_SETOWN_EX and F_GETOWN_EX take a pointer to a struct f_owner_ex
as argument:

struct f_owner_ex {
	int   type;
	pid_t pid;
};

Where type is one of F_OWNER_TID, F_OWNER_PID or F_OWNER_GID.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Tested-by: Nstephane eranian <eranian@googlemail.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce do_send_sig_info() and convert group_send_sig_info(),
send_sig_info(), do_send_specific() to use this helper.

Hopefully it will have more users soon, it allows to specify
specific/group behaviour via "bool group" argument.

Shaves 80 bytes from .text.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sys_delete_module() can set MODULE_STATE_GOING after
search_binary_handler() does try_module_get().  In this case
set_binfmt()->try_module_get() fails but since none of the callers
check the returned error, the task will run with the wrong old
->binfmt.

The proper fix should change all ->load_binary() methods, but we can
rely on fact that the caller must hold a reference to binfmt->module
and use __module_get() which never fails.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This changes tracehook_notify_jctl() so it's called with the siglock held,
and changes its argument and return value definition.  These clean-ups
make it a better fit for what new tracing hooks need to check.

Tracing needs the siglock here, held from the time TASK_STOPPED was set,
to avoid potential SIGCONT races if it wants to allow any blocking in its
tracing hooks.

This also folds the finish_stop() function into its caller
do_signal_stop().  The function is short, called only once and only
unconditionally.  It aids readability to fold it in.

[oleg@redhat.com: do not call tracehook_notify_jctl() in TASK_STOPPED state]
[oleg@redhat.com: introduce tracehook_finish_jctl() helper]
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The bug is old, it wasn't cause by recent changes.

Test case:

	static void *tfunc(void *arg)
	{
		int pid = (long)arg;

		assert(ptrace(PTRACE_ATTACH, pid, NULL, NULL) == 0);
		kill(pid, SIGKILL);

		sleep(1);
		return NULL;
	}

	int main(void)
	{
		pthread_t th;
		long pid = fork();

		if (!pid)
			pause();

		signal(SIGCHLD, SIG_IGN);
		assert(pthread_create(&th, NULL, tfunc, (void*)pid) == 0);

		int r = waitpid(-1, NULL, __WNOTHREAD);
		printf("waitpid: %d %m\n", r);

		return 0;
	}

Before the patch this program hangs, after this patch waitpid() correctly
fails with errno == -ECHILD.

The problem is, __ptrace_detach() reaps the EXIT_ZOMBIE tracee if its
->real_parent is our sub-thread and we ignore SIGCHLD.  But in this case
we should wake up other threads which can sleep in do_wait().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement reclaim from groups over their soft limit

Permit reclaim from memory cgroups on contention (via the direct reclaim
path).

memory cgroup soft limit reclaim finds the group that exceeds its soft
limit by the largest number of pages and reclaims pages from it and then
reinserts the cgroup into its correct place in the rbtree.

Add additional checks to mem_cgroup_hierarchical_reclaim() to detect long
loops in case all swap is turned off.  The code has been refactored and
the loop check (loop < 2) has been enhanced for soft limits.  For soft
limits, we try to do more targetted reclaim.  Instead of bailing out after
two loops, the routine now reclaims memory proportional to the size by
which the soft limit is exceeded.  The proportion has been empirically
determined.

[akpm@linux-foundation.org: build fix]
[kamezawa.hiroyu@jp.fujitsu.com: fix softlimit css refcnt handling]
[nishimura@mxp.nes.nec.co.jp: refcount of the "victim" should be decremented before exiting the loop]
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Organize cgroups over soft limit in a RB-Tree

Introduce an RB-Tree for storing memory cgroups that are over their soft
limit.  The overall goal is to

1. Add a memory cgroup to the RB-Tree when the soft limit is exceeded.
   We are careful about updates, updates take place only after a particular
   time interval has passed
2. We remove the node from the RB-Tree when the usage goes below the soft
   limit

The next set of patches will exploit the RB-Tree to get the group that is
over its soft limit by the largest amount and reclaim from it, when we
face memory contention.

[hugh.dickins@tiscali.co.uk: CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_PREEMPT=y fails to boot]
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NHugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add an interface to allow get/set of soft limits.  Soft limits for memory
plus swap controller (memsw) is currently not supported.  Resource
counters have been enhanced to support soft limits and new type
RES_SOFT_LIMIT has been added.  Unlike hard limits, soft limits can be
directly set and do not need any reclaim or checks before setting them to
a newer value.

Kamezawa-San raised a question as to whether soft limit should belong to
res_counter.  Since all resources understand the basic concepts of hard
and soft limits, it is justified to add soft limits here.  Soft limits are
a generic resource usage feature, even file system quotas support soft
limits.
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change the memory cgroup to remove the overhead associated with accounting
all pages in the root cgroup.  As a side-effect, we can no longer set a
memory hard limit in the root cgroup.

A new flag to track whether the page has been accounted or not has been
added as well.  Flags are now set atomically for page_cgroup,
pcg_default_flags is now obsolete and removed.

[akpm@linux-foundation.org: fix a few documentation glitches]
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Alter the ss->can_attach and ss->attach functions to be able to deal with
a whole threadgroup at a time, for use in cgroup_attach_proc.  (This is a
pre-patch to cgroup-procs-writable.patch.)

Currently, new mode of the attach function can only tell the subsystem
about the old cgroup of the threadgroup leader.  No subsystem currently
needs that information for each thread that's being moved, but if one were
to be added (for example, one that counts tasks within a group) this bit
would need to be reworked a bit to tell the subsystem the right
information.

[hidave.darkstar@gmail.com: fix build]
Signed-off-by: NBen Blum <bblum@google.com>
Signed-off-by: NPaul Menage <menage@google.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Reviewed-by: NMatt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Changes css_set freeing mechanism to be under RCU

This is a prepatch for making the procs file writable. In order to free the
old css_sets for each task to be moved as they're being moved, the freeing
mechanism must be RCU-protected, or else we would have to have a call to
synchronize_rcu() for each task before freeing its old css_set.
Signed-off-by: NBen Blum <bblum@google.com>
Signed-off-by: NPaul Menage <menage@google.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Previously there was the problem in which two processes from different pid
namespaces reading the tasks or procs file could result in one process
seeing results from the other's namespace.  Rather than one pidlist for
each file in a cgroup, we now keep a list of pidlists keyed by namespace
and file type (tasks versus procs) in which entries are placed on demand.
Each pidlist has its own lock, and that the pidlists themselves are passed
around in the seq_file's private pointer means we don't have to touch the
cgroup or its master list except when creating and destroying entries.
Signed-off-by: NBen Blum <bblum@google.com>
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

struct cgroup used to have a bunch of fields for keeping track of the
pidlist for the tasks file.  Those are now separated into a new struct
cgroup_pidlist, of which two are had, one for procs and one for tasks.
The way the seq_file operations are set up is changed so that just the
pidlist struct gets passed around as the private data.

Interface example: Suppose a multithreaded process has pid 1000 and other
threads with ids 1001, 1002, 1003:
$ cat tasks
1000
1001
1002
1003
$ cat cgroup.procs
1000
$
Signed-off-by: NBen Blum <bblum@google.com>
Signed-off-by: NPaul Menage <menage@google.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following series adds a "cgroup.procs" file to each cgroup that
reports unique tgids rather than pids, and allows all threads in a
threadgroup to be atomically moved to a new cgroup.

The subsystem "attach" interface is modified to support attaching whole
threadgroups at a time, which could introduce potential problems if any
subsystem were to need to access the old cgroup of every thread being
moved.  The attach interface may need to be revised if this becomes the
case.

Also added is functionality for read/write locking all CLONE_THREAD
fork()ing within a threadgroup, by means of an rwsem that lives in the
sighand_struct, for per-threadgroup-ness and also for sharing a cacheline
with the sighand's atomic count.  This scheme should introduce no extra
overhead in the fork path when there's no contention.

The final patch reveals potential for a race when forking before a
subsystem's attach function is called - one potential solution in case any
subsystem has this problem is to hang on to the group's fork mutex through
the attach() calls, though no subsystem yet demonstrates need for an
extended critical section.

This patch:

Revert

commit 096b7fe0
Author:     Li Zefan <lizf@cn.fujitsu.com>
AuthorDate: Wed Jul 29 15:04:04 2009 -0700
Commit:     Linus Torvalds <torvalds@linux-foundation.org>
CommitDate: Wed Jul 29 19:10:35 2009 -0700

    cgroups: fix pid namespace bug

This is in preparation for some clashing cgroups changes that subsume the
original commit's functionaliy.

The original commit fixed a pid namespace bug which Ben Blum fixed
independently (in the same way, but with different code) as part of a
series of patches.  I played around with trying to reconcile Ben's patch
series with Li's patch, but concluded that it was simpler to just revert
Li's, given that Ben's patch series contained essentially the same fix.
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix various Documentation/ paths in include/linux/.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Reviewed-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are many similar code in kernel for one object: convert time between
calendar time and broken-down time.

Here is some source I found:
  fs/ncpfs/dir.c
  fs/smbfs/proc.c
  fs/fat/misc.c
  fs/udf/udftime.c
  fs/cifs/netmisc.c
  net/netfilter/xt_time.c
  drivers/scsi/ips.c
  drivers/input/misc/hp_sdc_rtc.c
  drivers/rtc/rtc-lib.c
  arch/ia64/hp/sim/boot/fw-emu.c
  arch/m68k/mac/misc.c
  arch/powerpc/kernel/time.c
  arch/parisc/include/asm/rtc.h
  ...

We can make a common function for this type of conversion, At least we
can get following benefit:

1: Make kernel simple and unify
2: Easy to fix bug in converting code
3: Reduce clone of code in future
   For example, I'm trying to make ftrace display walltime,
   this patch will make me easy.

This code is based on code from glibc-2.6
Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce new truncate helpers truncate_pagecache and inode_newsize_ok.
vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and
into mm/truncate.c.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>