We disabled the ability to build fanotify in commit 7c534773.
This reverts that commit and allows people to build fanotify.
Signed-off-by: NEric Paris <eparis@redhat.com>

Signed-off-by: NFigo.zhang <figo1802@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Today's git tree fails to build on !CONFIG_BLOCK, due to upstream commit
367a51a3 ("fs: Add FITRIM ioctl"):

 include/linux/fs.h:36: error: expected specifier-qualifier-list before ‘uint64_t’
 include/linux/fs.h:36: error: expected specifier-qualifier-list before ‘uint64_t’
 include/linux/fs.h:36: error: expected specifier-qualifier-list before ‘uint64_t’

The commit adds uint64_t type usage to fs.h, but linux/types.h is not included
explicitly - it's only included implicitly via linux/blk_types.h, and there only if
CONFIG_BLOCK is enabled.

Add the explicit #include to fix this.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

SYNOPSIS
    size[4] Tfsync tag[2] fid[4] datasync[4]

    size[4] Rfsync tag[2]

DESCRIPTION

    The Tfsync transaction transfers ("flushes") all modified in-core data of
    file identified by fid to the disk device (or other  permanent  storage
    device)  where that  file  resides.

    If datasync flag is specified data will be fleshed but does not flush
    modified metadata unless  that  metadata  is  needed  in order to allow a
    subsequent data retrieval to be correctly handled.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Synopsis

	size[4] TReadlink tag[2] fid[4]
	size[4] RReadlink tag[2] target[s]

Description
	Readlink is used to return the contents of the symoblic link
        referred by fid. Contents of symboic link is returned as a
        response.

	target[s] - Contents of the symbolic link referred by fid.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Use V9FS_MAGIC as the file system type while filling kernel statfs
strucutre instead of using host file system magic number. Also move
the definition of V9FS_MAGIC from v9fs.h to standard magic.h file.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Synopsis

    size[4] TGetlock tag[2] fid[4] getlock[n]
    size[4] RGetlock tag[2] getlock[n]

Description

TGetlock is used to test for the existence of byte range posix locks on a file
identified by given fid. The reply contains getlock structure. If the lock could
be placed it returns F_UNLCK in type field of getlock structure.  Otherwise it
returns the details of the conflicting locks in the getlock structure

    getlock structure:
      type[1] - Type of lock: F_RDLCK, F_WRLCK
      start[8] - Starting offset for lock
      length[8] - Number of bytes to check for the lock
             If length is 0, check for lock in all bytes starting at the location
            'start' through to the end of file
      pid[4] - PID of the process that wants to take lock/owns the task
               in case of reply
      client[4] - Client id of the system that owns the process which
                  has the conflicting lock
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Synopsis

    size[4] TLock tag[2] fid[4] flock[n]
    size[4] RLock tag[2] status[1]

Description

Tlock is used to acquire/release byte range posix locks on a file
identified by given fid. The reply contains status of the lock request

    flock structure:
        type[1] - Type of lock: F_RDLCK, F_WRLCK, F_UNLCK
        flags[4] - Flags could be either of
          P9_LOCK_FLAGS_BLOCK - Blocked lock request, if there is a
            conflicting lock exists, wait for that lock to be released.
          P9_LOCK_FLAGS_RECLAIM - Reclaim lock request, used when client is
            trying to reclaim a lock after a server restrart (due to crash)
        start[8] - Starting offset for lock
        length[8] - Number of bytes to lock
          If length is 0, lock all bytes starting at the location 'start'
          through to the end of file
        pid[4] - PID of the process that wants to take lock
        client_id[4] - Unique client id

        status[1] - Status of the lock request, can be
          P9_LOCK_SUCCESS(0), P9_LOCK_BLOCKED(1), P9_LOCK_ERROR(2) or
          P9_LOCK_GRACE(3)
          P9_LOCK_SUCCESS - Request was successful
          P9_LOCK_BLOCKED - A conflicting lock is held by another process
          P9_LOCK_ERROR - Error while processing the lock request
          P9_LOCK_GRACE - Server is in grace period, it can't accept new lock
            requests in this period (except locks with
            P9_LOCK_FLAGS_RECLAIM flag set)
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

SYNOPSIS
    size[4] Tfsync tag[2] fid[4]

    size[4] Rfsync tag[2]

DESCRIPTION

The Tfsync transaction transfers ("flushes") all modified in-core data of
file identified by fid to the disk device (or other  permanent  storage
device)  where that  file  resides.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NArun R Bharadwaj <arun@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Unfortunately perf can't deal with anything other than direct structure
accesses in the TP_printk() section.  It will drop dead when it sees
jbd2_dev_to_name() in the "print fmt" section of the tracepoint.

Addresses-Google-Bug: 3138508
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Commit 84061e07 fixed an accounting bug only to introduce the
possibility of a kernel OOPS if the journal has a non-zero j_errno
field indicating that the file system had detected a fs inconsistency.
After the journal replay, if the journal superblock indicates that the
file system has an error, this indication is transfered to the file
system and then ext4_commit_super() is called to write this to the
disk.

But since the percpu counters are now initialized after the journal
replay, the call to ext4_commit_super() will cause a kernel oops since
it needs to use the percpu counters the ext4 superblock structure.

The fix is to skip setting the ext4 free block and free inode fields
if the percpu counter has not been set.

Thanks to Ken Sumrall for reporting and analyzing the root causes of
this bug.

Addresses-Google-Bug: #3054080
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This is analogous to Jan Kara's commit,
f446daae
mm: implement writeback livelock avoidance using page tagging

but since we forked write_cache_pages, we need to reimplement
it there (and in ext4_da_writepages, since range_cyclic handling
was moved to there)

If you start a large buffered IO to a file, and then set
fsync after it, you'll find that fsync does not complete
until the other IO stops.

If you continue re-dirtying the file (say, putting dd
with conv=notrunc in a loop), when fsync finally completes
(after all IO is done), it reports via tracing that
it has written many more pages than the file contains;
in other words it has synced and re-synced pages in
the file multiple times.

This then leads to problems with our writeback_index
update, since it advances it by pages written, and
essentially sets writeback_index off the end of the
file...

With the following patch, we only sync as much as was
dirty at the time of the sync.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Adds an filesystem independent ioctl to allow implementation of file
system batched discard support. I takes fstrim_range structure as an
argument. fstrim_range is definec in the include/fs.h and its
definition is as follows.

struct fstrim_range {
	start;
	len;
	minlen;
}

start	- first Byte to trim
len	- number of Bytes to trim from start
minlen	- minimum extent length to trim, free extents shorter than this
	  number of Bytes will be ignored. This will be rounded up to fs
	  block size.

It is also possible to specify NULL as an argument. In this case the
arguments will set itself as follows:

start = 0;
len = ULLONG_MAX;
minlen = 0;

So it will trim the whole file system at one run.

After the FITRIM is done, the number of actually discarded Bytes is stored
in fstrim_range.len to give the user better insight on how much storage
space has been really released for wear-leveling.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Reviewed-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Many tracepoints were populating an ext4_allocation_context
to pass in, but this requires a slab allocation even when
tracepoints are off.  In fact, 4 of 5 of these allocations
were only for tracing.  In addition, we were only using a
small fraction of the 144 bytes of this structure for this
purpose.

We can do away with all these alloc/frees of the ac and
simply pass in the bits we care about, instead.

I tested this by turning on tracing and running through
xfstests on x86_64.  I did not actually do anything with
the trace output, however.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Our QA reported an oops in the ext4_mb_release_group_pa tracing,
and Josef Bacik pointed out that it was because we may have a
non-null but uninitialized ac_inode in the allocation context.

I can reproduce it when running xfstests with ext4 tracepoints on, 
on a CONFIG_SLAB_DEBUG kernel.

We call trace_ext4_mb_release_group_pa from 2 places, 
ext4_mb_discard_group_preallocations and 
ext4_mb_discard_lg_preallocations

In both cases we allocate an ac as a container just for tracing (!)
and never fill in the ac_inode.  There's no reason to be assigning,
testing, or printing it as far as I can see, so just remove it from
the tracepoint.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This is done the same way as helper sb_issue_discard for
blkdev_issue_discard.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

ac->inode is set to null in function ext4_mb_release_group_pa(),
and then trace_ext4_mballoc_discard(ac) is called, the kernel
will panic.

BUG: unable to handle kernel NULL pointer dereference at 000000a4
IP: [<f87e1714>] ftrace_raw_event_ext4__mballoc+0x54/0xc0 [ext4]
*pdpt = 0000000000abd001 *pde = 0000000000000000
Oops: 0000 [#1] SMP

Pid: 550, comm: flush-8:16 Not tainted 2.6.36-rc1 #1 SE7320EP2/Altos G530
EIP: 0060:[<f87e1714>] EFLAGS: 00010206 CPU: 1
EIP is at ftrace_raw_event_ext4__mballoc+0x54/0xc0 [ext4]
EAX: f32ac840 EBX: f3f1cf88 ECX: f32ac840 EDX: 00000000
ESI: f32ac83c EDI: f880b9d8 EBP: 00000000 ESP: f4b77ae4
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process flush-8:16 (pid: 550, ti=f4b76000 task=f613e540 task.ti=f4b76000)
Call Trace:
 [<f87f5ac1>] ? ext4_mb_release_group_pa+0x121/0x150 [ext4]
 [<f87f8356>] ? ext4_mb_discard_group_preallocations+0x336/0x400 [ext4]
 [<f87fb7f1>] ? ext4_mb_new_blocks+0x3d1/0x4f0 [ext4]
 [<c05a6c5b>] ? __make_request+0x10b/0x440
 [<f87f1fb4>] ? ext4_ext_map_blocks+0x1334/0x1980 [ext4]
 [<c04ac78a>] ? rb_reserve_next_event+0xaa/0x3b0
 [<f87d18d6>] ? ext4_map_blocks+0xd6/0x1d0 [ext4]
 [<f87d2da7>] ? mpage_da_map_blocks+0xc7/0x8a0 [ext4]
 [<c04c8a68>] ? find_get_pages_tag+0x38/0x110
 [<c04d23a5>] ? __pagevec_release+0x15/0x20
 [<f87d3ca5>] ? ext4_da_writepages+0x2b5/0x5d0 [ext4]
 [<c04cfbe0>] ? __writepage+0x0/0x30
 [<c04d0e34>] ? do_writepages+0x14/0x30
 [<c0526600>] ? writeback_single_inode+0xa0/0x240
 [<c0526971>] ? writeback_sb_inodes+0xc1/0x180
 [<c0526ab8>] ? writeback_inodes_wb+0x88/0x140
 [<c0526d7b>] ? wb_writeback+0x20b/0x320
 [<c045aca7>] ? lock_timer_base+0x27/0x50
 [<c0526fe0>] ? wb_do_writeback+0x150/0x190
 [<c05270a8>] ? bdi_writeback_thread+0x88/0x1f0
 [<c043b680>] ? complete+0x40/0x60
 [<c0527020>] ? bdi_writeback_thread+0x0/0x1f0
 [<c0469474>] ? kthread+0x74/0x80
 [<c0469400>] ? kthread+0x0/0x80
 [<c040a23e>] ? kernel_thread_helper+0x6/0x10
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This fixes a hang seen in jbd2_journal_release_jbd_inode
on a lot of Power 6 systems running with ext4. When we get
in the hung state, all I/O to the disk in question gets blocked
where we stay indefinitely. Looking at the task list, I can see
we are stuck in jbd2_journal_release_jbd_inode waiting on a
wake up. I added some debug code to detect this scenario and
dump additional data if we were stuck in jbd2_journal_release_jbd_inode
for longer than 30 minutes. When it hit, I was able to see that
i_flags was 0, suggesting we missed the wake up.

This patch changes i_flags to be an unsigned long, uses bit operators
to access it, and adds barriers around the accesses. Prior to applying
this patch, we were regularly hitting this hang on numerous systems
in our test environment. After applying the patch, the hangs no longer
occur.
Signed-off-by: NBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This make epoll use hrtimers for the timeout value which prevents
epoll_wait() from timing out up to a millisecond early.

This mirrors the behavior of select() and poll().
Signed-off-by: NShawn Bohrer <shawn.bohrer@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: NDavide Libenzi <davidel@xmailserver.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NZimny Lech <napohybelskurwysynom2010@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As each board and system has different memory for ramoops.  It's better to
define the platform data instead of module params.

[akpm@linux-foundation.org: fix ramoops_remove() return type]
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a new __kfifo_int_must_check_helper() helper function, which is needed
for kfifo_alloc() to return the right signed integer value.

The origin __kfifo_must_check_helper() helper was renamed into
__kfifo_uint_must_check_helper() to show the sign which is expected and
returned.

(And revert the temporary disabling of __kfifo_must_check_helper())
Signed-off-by: NStefani Seibold <stefani@seibold.net>
Acked-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>

The taskstats interface uses microsecond granularity for the user and
system time values.  The conversion from cputime to the taskstats values
uses the cputime_to_msecs primitive which effectively limits the
granularity to milliseconds.  Add the cputime_to_usecs primitive for
architectures that have better, more precise CPU time values.  Remove
cputime_to_msecs primitive because there are no more users left.
Signed-off-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: Luck Tony <tony.luck@intel.com>
Cc: Shailabh Nagar <nagar1234@in.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Shailabh Nagar <nagar@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

RapidIO spec v.2.1 adds Idle Sequence 2 into LP-Serial Physical Layer.
The fix ensures that corresponding bits are not corrupted during error
handling.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Detects RIO link to the already enumerated device and properly sets links
between device objects.  Changes to the enumeration/discovery logic:

1. Use Master Enable bit to signal end of the enumeration - agents may
   start their discovery process as soon as they see this bit set
   (Component Tag register was used before for this purpose).

2. Enumerator sets Component Tag (!= 0) immediately during device
   setup.  This allows to identify the device if the redundant route
   exists in a RIO system.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add the RIO switch driver and definitions for IDT CPS-1848 and CPS-1616
Gen2 devices.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

1. Change to create attribute "routes" only for switches.

2. Add a switch-specific callback to create/remove proprietary attributes.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The default error-stopped state handler provides recovery mechanism as
defined by RIO specification.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Create back and forward links between RIO devices.  These links are
intended for use by error management and hot-plug extensions.  Links for
redundant RIO connections between switches are not set (will be fixed in a
separate patch).
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The switch port information is obtained and stored during RIO device
setup.  Therefore repeated reads from Switch Port Information CAR may be
removed.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This set of RapidIO patches extends support for standard error recovery
mechanism and adds new IDT Gen2 sRIO switch devices - CPS-1848 and
CPS-1616.  Implementation of the standard error-stopped state recovery
mechanism (as defined by the RapidIO specification) is required for the
new switches.

Version 2 of this set of patches addresses received comments and fixes an
error notification setup issue found in the idt_gen2.c after the first
version was released.

This patch:

Make RapidIO devices appear in /sys/devices/rapidio directory instead of
top of /sys/devices directory.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support for extended byte synchronous mode feature of hardware.
Signed-off-by: NPaul Fulghum <paulkf@microgate.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In /proc/stat, the number of per-IRQ event is shown by making a sum each
irq's events on all cpus.  But we can make use of kstat_irqs().

kstat_irqs() do the same calculation, If !CONFIG_GENERIC_HARDIRQ,
it's not a big cost. (Both of the number of cpus and irqs are small.)

If a system is very big and CONFIG_GENERIC_HARDIRQ, it does

	for_each_irq()
		for_each_cpu()
			- look up a radix tree
			- read desc->irq_stat[cpu]
This seems not efficient. This patch adds kstat_irqs() for
CONFIG_GENRIC_HARDIRQ and change the calculation as

	for_each_irq()
		look up radix tree
		for_each_cpu()
			- read desc->irq_stat[cpu]

This reduces cost.

A test on (4096cpusp, 256 nodes, 4592 irqs) host (by Jack Steiner)

%time cat /proc/stat > /dev/null

Before Patch:	 2.459 sec
After Patch :	  .561 sec

[akpm@linux-foundation.org: unexport kstat_irqs, coding-style tweaks]
[akpm@linux-foundation.org: fix unused variable 'per_irq_sum']
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: NJack Steiner <steiner@sgi.com>
Acked-by: NJack Steiner <steiner@sgi.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

/proc/stat shows the total number of all interrupts to each cpu.  But when
the number of IRQs are very large, it take very long time and 'cat
/proc/stat' takes more than 10 secs.  This is because sum of all irq
events are counted when /proc/stat is read.  This patch adds "sum of all
irq" counter percpu and reduce read costs.

The cost of reading /proc/stat is important because it's used by major
applications as 'top', 'ps', 'w', etc....

A test on a mechin (4096cpu, 256 nodes, 4592 irqs) shows

 %time cat /proc/stat > /dev/null
 Before Patch:  12.627 sec
 After  Patch:  2.459 sec
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: NJack Steiner <steiner@sgi.com>
Acked-by: NJack Steiner <steiner@sgi.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec
itself and we can reuse ->cred_guard_mutex for it.  Yes, concurrent
execve() has no worth.

Let's move ->cred_guard_mutex from task_struct to signal_struct.  It
naturally prevent multiple-threads-inside-exec.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NRoland McGrath <roland@redhat.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

lock_task_sighand() grabs sighand->siglock in case of returning non-NULL
but unlock_task_sighand() releases it unconditionally.  This leads sparse
to complain about the lock context imbalance.  Rename and wrap
lock_task_sighand() using __cond_lock() macro to make sparse happy.
Suggested-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.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>

Fix up the arguments to arch_ptrace() to take account of the fact that
@addr and @data are now unsigned long rather than long as of a preceding
patch in this series.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Cc: <linux-arch@vger.kernel.org>
Acked-by: NRoland McGrath <roland@redhat.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since userspace API of ptrace syscall defines @addr and @data as void
pointers, it would be more appropriate to define them as unsigned long in
kernel.  Therefore related functions are changed also.

'unsigned long' is typically used in other places in kernel as an opaque
data type and that using this helps cleaning up a lot of warnings from
sparse.
Suggested-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
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>

The ns_cgroup is a control group interacting with the namespaces.  When a
new namespace is created, a corresponding cgroup is automatically created
too.  The cgroup name is the pid of the process who did 'unshare' or the
child of 'clone'.

This cgroup is tied with the namespace because it prevents a process to
escape the control group and use the post_clone callback, so the child
cgroup inherits the values of the parent cgroup.

Unfortunately, the more we use this cgroup and the more we are facing
problems with it:

(1) when a process unshares, the cgroup name may conflict with a
    previous cgroup with the same pid, so unshare or clone return -EEXIST

(2) the cgroup creation is out of control because there may have an
    application creating several namespaces where the system will
    automatically create several cgroups in his back and let them on the
    cgroupfs (eg.  a vrf based on the network namespace).

(3) the mix of (1) and (2) force an administrator to regularly check
    and clean these cgroups.

This patchset removes the ns_cgroup by adding a new flag to the cgroup and
the cgroupfs mount option.  It enables the copy of the parent cgroup when
a child cgroup is created.  We can then safely remove the ns_cgroup as
this flag brings a compatibility.  We have now to manually create and add
the task to a cgroup, which is consistent with the cgroup framework.

This patch:

Sent as an answer to a previous thread around the ns_cgroup.

https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html

It adds a control file 'clone_children' for a cgroup.  This control file
is a boolean specifying if the child cgroup should be a clone of the
parent cgroup or not.  The default value is 'false'.

This flag makes the child cgroup to call the post_clone callback of all
the subsystem, if it is available.

At present, the cpuset is the only one which had implemented the
post_clone callback.

The option can be set at mount time by specifying the 'clone_children'
mount option.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: NSerge E. Hallyn <serge.hallyn@canonical.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: NPaul Menage <menage@google.com>
Reviewed-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Cc: Matt Helsley <matthltc@us.ibm.com>
Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>