Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

The conversion of all of the users is not done yet there are too many to change
in one go and leave the code reviewable. For now I change just the header and
a few trivial users and rely on CONFIG_UIDGID_STRICT_TYPE_CHECKS not being set
to ensure that the code will still compile during the transition.

Helper functions i_uid_read, i_uid_write, i_gid_read, i_gid_write are added
so that in most cases filesystems can avoid the complexities of multiple user
namespaces and can concentrate on moving their raw numeric values into and
out of the vfs data structures.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

These function are no longer needed replace them with their more useful equivalents.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

cred.h and a few trivial users of struct cred are changed.  The rest of the users
of struct cred are left for other patches as there are too many changes to make
in one go and leave the change reviewable.  If the user namespace is disabled and
CONFIG_UIDGID_STRICT_TYPE_CHECKS are disabled the code will contiue to compile
and behave correctly.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

As a first step to converting struct cred to be all kuid_t and kgid_t
values convert the group values stored in group_info to always be
kgid_t values.   Unless user namespaces are used this change should
have no effect.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

- Convert the old uid mapping functions into compatibility wrappers
- Add a uid/gid mapping layer from user space uid and gids to kernel
  internal uids and gids that is extent based for simplicty and speed.
  * Working with number space after mapping uids/gids into their kernel
    internal version adds only mapping complexity over what we have today,
    leaving the kernel code easy to understand and test.
- Add proc files /proc/self/uid_map /proc/self/gid_map
  These files display the mapping and allow a mapping to be added
  if a mapping does not exist.
- Allow entering the user namespace without a uid or gid mapping.
  Since we are starting with an existing user our uids and gids
  still have global mappings so are still valid and useful they just don't
  have local mappings.  The requirement for things to work are global uid
  and gid so it is odd but perfectly fine not to have a local uid
  and gid mapping.
  Not requiring global uid and gid mappings greatly simplifies
  the logic of setting up the uid and gid mappings by allowing
  the mappings to be set after the namespace is created which makes the
  slight weirdness worth it.
- Make the mappings in the initial user namespace to the global
  uid/gid space explicit.  Today it is an identity mapping
  but in the future we may want to twist this for debugging, similar
  to what we do with jiffies.
- Document the memory ordering requirements of setting the uid and
  gid mappings.  We only allow the mappings to be set once
  and there are no pointers involved so the requirments are
  trivial but a little atypical.

Performance:

In this scheme for the permission checks the performance is expected to
stay the same as the actuall machine instructions should remain the same.

The worst case I could think of is ls -l on a large directory where
all of the stat results need to be translated with from kuids and
kgids to uids and gids.  So I benchmarked that case on my laptop
with a dual core hyperthread Intel i5-2520M cpu with 3M of cpu cache.

My benchmark consisted of going to single user mode where nothing else
was running. On an ext4 filesystem opening 1,000,000 files and looping
through all of the files 1000 times and calling fstat on the
individuals files.  This was to ensure I was benchmarking stat times
where the inodes were in the kernels cache, but the inode values were
not in the processors cache.  My results:

v3.4-rc1:         ~= 156ns (unmodified v3.4-rc1 with user namespace support disabled)
v3.4-rc1-userns-: ~= 155ns (v3.4-rc1 with my user namespace patches and user namespace support disabled)
v3.4-rc1-userns+: ~= 164ns (v3.4-rc1 with my user namespace patches and user namespace support enabled)

All of the configurations ran in roughly 120ns when I performed tests
that ran in the cpu cache.

So in summary the performance impact is:
1ns improvement in the worst case with user namespace support compiled out.
8ns aka 5% slowdown in the worst case with user namespace support compiled in.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

- Transform userns->creator from a user_struct reference to a simple
  kuid_t, kgid_t pair.

  In cap_capable this allows the check to see if we are the creator of
  a namespace to become the classic suser style euid permission check.

  This allows us to remove the need for a struct cred in the mapping
  functions and still be able to dispaly the user namespace creators
  uid and gid as 0.

- Remove the now unnecessary delayed_work in free_user_ns.

  All that is left for free_user_ns to do is to call kmem_cache_free
  and put_user_ns.  Those functions can be called in any context
  so call them directly from free_user_ns removing the need for delayed work.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Modify alloc_uid to take a kuid and make the user hash table global.
Stop holding a reference to the user namespace in struct user_struct.

This simplifies the code and makes the per user accounting not
care about which user namespace a uid happens to appear in.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Make it possible to easily switch between strong mandatory
type checks and relaxed type checks so that the code can
easily be tested with the type checks and then built
with the strong type checks disabled so the resulting
code can be used.

Require strong mandatory type checks when enabling the user namespace.
It is very simple to make a typo and use the wrong type allowing
conversions to/from userspace values to be bypassed by accident,
the strong type checks prevent this.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Start distinguishing between internal kernel uids and gids and
values that userspace can use.  This is done by introducing two
new types: kuid_t and kgid_t.  These types and their associated
functions are infrastructure are declared in the new header
uidgid.h.

Ultimately there will be a different implementation of the mapping
functions for use with user namespaces.  But to keep it simple
we introduce the mapping functions first to separate the meat
from the mechanical code conversions.

Export overflowuid and overflowgid so we can use from_kuid_munged
and from_kgid_munged in modular code.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

This represents a change in strategy of how to handle user namespaces.
Instead of tagging everything explicitly with a user namespace and bulking
up all of the comparisons of uids and gids in the kernel,  all uids and gids
in use will have a mapping to a flat kuid and kgid spaces respectively.  This
allows much more of the existing logic to be preserved and in general
allows for faster code.

In this new and improved world we allow someone to utiliize capabilities
over an inode if the inodes owner mapps into the capabilities holders user
namespace and the user has capabilities in their user namespace.  Which
is simple and efficient.

Moving the fs uid comparisons to be comparisons in a flat kuid space
follows in later patches, something that is only significant if you
are using user namespaces.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

With a user_ns reference in struct cred the only user of the user namespace
reference in struct user_struct is to keep the uid hash table alive.

The user_namespace reference in struct user_struct will be going away soon, and
I have removed all of the references.  Rename the field from user_ns to _user_ns
so that the compiler can verify nothing follows the user struct to the user
namespace anymore.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

I am about to remove the struct user_namespace reference from struct user_struct.
So keep an explicit track of the parent user namespace.

Take advantage of this new reference and replace instances of user_ns->creator->user_ns
with user_ns->parent.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

struct user_struct will shortly loose it's user_ns reference
so make the cred user_ns reference a proper reference complete
with reference counting.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

There is no release_uids function remove the declaration from sched.h
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... implemented that way since the next commit will leave it
almost alone in ext2_fs.h - most of the file (including
struct ext2_super_block) is going to move to fs/ext2/ext2.h.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Since the on-disk format has been stable for quite some time, users
should either use the headers provided by libext2fs or keep a private
copy of this header. For the full discussion, see this thread:

	https://lkml.org/lkml/2012/3/21/516

While at it, this commit removes all __KERNEL__ guards, which are now
unnecessary.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Andreas Dilger <aedilger@gmail.com>
Cc: linux-ext4@vger.kernel.org

The thaw operation was used by the balloon driver, but after the last
commit there's no reason to have separate thaw and restore callbacks.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

power_usage is always assigned a negative value and should be declared
a signed integer
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Currently when a CPU is off-lined it enters either MWAIT-based idle or,
if MWAIT is not desired or supported, HLT-based idle (which places the
processor in C1 state). This patch allows processors without MWAIT
support to stay in states deeper than C1.
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

acpi_dev_run_wake() is a generic function which can be used by
other subsystem too. Rename it to acpi_pm_device_run_wake, to be
consistent with acpi_pm_device_sleep_wake.

Then move it to ACPI core.
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NLin Ming <ming.m.lin@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

As far as I can see, this field is never used in the code.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NLen Brown <len.brown@intel.com>

All the modules name are ro-data, it is never copied to the array.

eg.

static struct cpuidle_driver intel_idle_driver = {
        .name = "intel_idle",
        .owner = THIS_MODULE,
};

It safe to assign the pointer of this ro-data to a const char *.
By this way we save 12 bytes.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Tested-by: NDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Some C states of new CPU might be not good.  One reason is BIOS might
configure them incorrectly.  To help developers root cause it quickly, the
patch adds a new sysfs entry, so developers could disable specific C state
manually.

In addition, C state might have much impact on performance tuning, as it
takes much time to enter/exit C states, which might delay interrupt
processing.  With the new debug option, developers could check if a deep C
state could impact performance and how much impact it could cause.

Also add this option in Documentation/cpuidle/sysfs.txt.

[akpm@linux-foundation.org: check kstrtol return value]
Signed-off-by: NShuoX Liu <shuox.liu@intel.com>
Reviewed-by: NYanmin Zhang <yanmin_zhang@intel.com>
Reviewed-and-Tested-by: NDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLen Brown <len.brown@intel.com>

Devices may share same list of power resources in _PR0, for example

Device(Dev0)
{
	Name (_PR0, Package (0x01)
	{
		P0PR,
		P1PR
	})
}

Device(Dev1)
{
	Name (_PR0, Package (0x01)
	{
		P0PR,
		P1PR
	}
}

Assume Dev0 and Dev1 were runtime suspended.
Then Dev0 is resumed first and it goes into D0 state.
But Dev1 is left in D0_Uninitialised state.

This is wrong. In this case, Dev1 must be resumed too.

In order to hand this case, each power resource maintains a list of
devices which relies on it.

When power resource is ON, it will check if the devices on its list
can be resumed. The device can only be resumed when all the power
resouces of its _PR0 are ON.
Signed-off-by: NLin Ming <ming.m.lin@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Version 20120320.
Signed-off-by: NBob Moore <robert.moore@intel.com>
Signed-off-by: NLin Ming <ming.m.lin@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

A series of radix tree cleanups, and usage of them in the core pagecache
code.

Micro-benchmark:

lookup 14 slots (typical page-vector size)
in radix-tree there earch <step> slot filled and tagged
before/after - nsec per full scan through tree

* Intel Sandy Bridge i7-2620M 4Mb L3
New code always faster

* AMD Athlon 6000+ 2x1Mb L2, without L3
New code generally faster,
Minor degradation (marked with "*") for huge sparse trees

* i386 on Sandy Bridge
New code faster for common cases: tagged and dense trees.
Some degradations for non-tagged lookup on sparse trees.

Ideally, there might help __ffs() analog for searching first non-zero
long element in array, gcc sometimes cannot optimize this loop corretly.

Numbers:

CPU: Intel Sandy Bridge i7-2620M 4Mb L3

radix-tree with 1024 slots:

tagged lookup

step  1      before  7156        after  3613
step  2      before  5399        after  2696
step  3      before  4779        after  1928
step  4      before  4456        after  1429
step  5      before  4292        after  1213
step  6      before  4183        after  1052
step  7      before  4157        after  951
step  8      before  4016        after  812
step  9      before  3952        after  851
step  10     before  3937        after  732
step  11     before  4023        after  709
step  12     before  3872        after  657
step  13     before  3892        after  633
step  14     before  3720        after  591
step  15     before  3879        after  578
step  16     before  3561        after  513

normal lookup

step  1      before  4266       after  3301
step  2      before  2695       after  2129
step  3      before  2083       after  1712
step  4      before  1801       after  1534
step  5      before  1628       after  1313
step  6      before  1551       after  1263
step  7      before  1475       after  1185
step  8      before  1432       after  1167
step  9      before  1373       after  1092
step  10     before  1339       after  1134
step  11     before  1292       after  1056
step  12     before  1319       after  1030
step  13     before  1276       after  1004
step  14     before  1256       after  987
step  15     before  1228       after  992
step  16     before  1247       after  999

radix-tree with 1024*1024*128 slots:

tagged lookup

step  1      before  1086102841  after  674196409
step  2      before  816839155   after  498138306
step  7      before  599728907   after  240676762
step  15     before  555729253   after  185219677
step  63     before  606637748   after  128585664
step  64     before  608384432   after  102945089
step  65     before  596987114   after  123996019
step  128    before  304459225   after  56783056
step  256    before  158846855   after  31232481
step  512    before  86085652    after  18950595
step  12345  before  6517189     after  1674057

normal lookup

step  1      before  626064869  after  544418266
step  2      before  418809975  after  336321473
step  7      before  242303598  after  207755560
step  15     before  208380563  after  176496355
step  63     before  186854206  after  167283638
step  64     before  176188060  after  170143976
step  65     before  185139608  after  167487116
step  128    before  88181865   after  86913490
step  256    before  45733628   after  45143534
step  512    before  24506038   after  23859036
step  12345  before  2177425    after  2018662

* AMD Athlon 6000+ 2x1Mb L2, without L3

radix-tree with 1024 slots:

tag-lookup

step  1      before  8164        after  5379
step  2      before  5818        after  5581
step  3      before  4959        after  4213
step  4      before  4371        after  3386
step  5      before  4204        after  2997
step  6      before  4950        after  2744
step  7      before  4598        after  2480
step  8      before  4251        after  2288
step  9      before  4262        after  2243
step  10     before  4175        after  2131
step  11     before  3999        after  2024
step  12     before  3979        after  1994
step  13     before  3842        after  1929
step  14     before  3750        after  1810
step  15     before  3735        after  1810
step  16     before  3532        after  1660

normal-lookup

step  1      before  7875        after  5847
step  2      before  4808        after  4071
step  3      before  4073        after  3462
step  4      before  3677        after  3074
step  5      before  4308        after  2978
step  6      before  3911        after  3807
step  7      before  3635        after  3522
step  8      before  3313        after  3202
step  9      before  3280        after  3257
step  10     before  3166        after  3083
step  11     before  3066        after  3026
step  12     before  2985        after  2982
step  13     before  2925        after  2924
step  14     before  2834        after  2808
step  15     before  2805        after  2803
step  16     before  2647        after  2622

radix-tree with 1024*1024*128 slots:

tag-lookup

step  1      before  1288059720  after  951736580
step  2      before  961292300   after  884212140
step  7      before  768905140   after  547267580
step  15     before  771319480   after  456550640
step  63     before  504847640   after  242704304
step  64     before  392484800   after  177920786
step  65     before  491162160   after  246895264
step  128    before  208084064   after  97348392
step  256    before  112401035   after  51408126
step  512    before  75825834    after  29145070
step  12345  before  5603166     after  2847330

normal-lookup

step  1      before  1025677120  after  861375100
step  2      before  647220080   after  572258540
step  7      before  505518960   after  484041813
step  15     before  430483053   after  444815320	*
step  63     before  388113453   after  404250546	*
step  64     before  374154666   after  396027440	*
step  65     before  381423973   after  396704853	*
step  128    before  190078700   after  202619384	*
step  256    before  100886756   after  102829108	*
step  512    before  64074505    after  56158720
step  12345  before  4237289     after  4422299		*

* i686 on Sandy bridge

radix-tree with 1024 slots:

tagged lookup

step  1      before  7990        after  4019
step  2      before  5698        after  2897
step  3      before  5013        after  2475
step  4      before  4630        after  1721
step  5      before  4346        after  1759
step  6      before  4299        after  1556
step  7      before  4098        after  1513
step  8      before  4115        after  1222
step  9      before  3983        after  1390
step  10     before  4077        after  1207
step  11     before  3921        after  1231
step  12     before  3894        after  1116
step  13     before  3840        after  1147
step  14     before  3799        after  1090
step  15     before  3797        after  1059
step  16     before  3783        after  745

normal lookup

step  1      before  5103       after  3499
step  2      before  3299       after  2550
step  3      before  2489       after  2370
step  4      before  2034       after  2302		*
step  5      before  1846       after  2268		*
step  6      before  1752       after  2249		*
step  7      before  1679       after  2164		*
step  8      before  1627       after  2153		*
step  9      before  1542       after  2095		*
step  10     before  1479       after  2109		*
step  11     before  1469       after  2009		*
step  12     before  1445       after  2039		*
step  13     before  1411       after  2013		*
step  14     before  1374       after  2046		*
step  15     before  1340       after  1975		*
step  16     before  1331       after  2000		*

radix-tree with 1024*1024*128 slots:

tagged lookup

step  1      before  1225865377  after  667153553
step  2      before  842427423   after  471533007
step  7      before  609296153   after  276260116
step  15     before  544232060   after  226859105
step  63     before  519209199   after  141343043
step  64     before  588980279   after  141951339
step  65     before  521099710   after  138282060
step  128    before  298476778   after  83390628
step  256    before  149358342   after  43602609
step  512    before  76994713    after  22911077
step  12345  before  53286669     after  1472111

normal lookup

step  1      before  819284564  after  533635310
step  2      before  512421605  after  364956155
step  7      before  271443305  after  305721345	*
step  15     before  223591630  after  273960216	*
step  63     before  190320247  after  217770207	*
step  64     before  178538168  after  267411372	*
step  65     before  186400423  after  215347937	*
step  128    before  88106045   after  140540612	*
step  256    before  44812420   after  70660377		*
step  512    before  24435438   after  36328275		*
step  12345  before  2123924    after  2148062		*

bloat-o-meter delta for this patchset + patchset with related shmem cleanups

bloat-o-meter: x86_64

add/remove: 4/3 grow/shrink: 5/6 up/down: 928/-939 (-11)
function                                     old     new   delta
radix_tree_next_chunk                          -     499    +499
shmem_unuse                                  428     554    +126
shmem_radix_tree_replace                     131     227     +96
find_get_pages_tag                           354     419     +65
find_get_pages_contig                        345     407     +62
find_get_pages                               362     396     +34
__kstrtab_radix_tree_next_chunk                -      22     +22
__ksymtab_radix_tree_next_chunk                -      16     +16
__kcrctab_radix_tree_next_chunk                -       8      +8
radix_tree_gang_lookup_slot                  204     203      -1
static.shmem_xattr_set                       384     381      -3
radix_tree_gang_lookup_tag_slot              208     191     -17
radix_tree_gang_lookup                       231     187     -44
radix_tree_gang_lookup_tag                   247     199     -48
shmem_unlock_mapping                         278     190     -88
__lookup                                     217       -    -217
__lookup_tag                                 242       -    -242
radix_tree_locate_item                       279       -    -279

bloat-o-meter: i386

add/remove: 3/3 grow/shrink: 8/9 up/down: 1075/-1275 (-200)
function                                     old     new   delta
radix_tree_next_chunk                          -     757    +757
shmem_unuse                                  352     449     +97
find_get_pages_contig                        269     322     +53
shmem_radix_tree_replace                     113     154     +41
find_get_pages_tag                           277     318     +41
dcache_dir_lseek                             426     458     +32
__kstrtab_radix_tree_next_chunk                -      22     +22
vc_do_resize                                 968     977      +9
snd_pcm_lib_read1                            725     733      +8
__ksymtab_radix_tree_next_chunk                -       8      +8
netlbl_cipsov4_list                         1120    1127      +7
find_get_pages                               293     291      -2
new_slab                                     467     459      -8
bitfill_unaligned_rev                        425     417      -8
radix_tree_gang_lookup_tag_slot              177     146     -31
blk_dump_cmd                                 267     229     -38
radix_tree_gang_lookup_slot                  212     134     -78
shmem_unlock_mapping                         221     128     -93
radix_tree_gang_lookup_tag                   275     162    -113
radix_tree_gang_lookup                       255     126    -129
__lookup                                     227       -    -227
__lookup_tag                                 271       -    -271
radix_tree_locate_item                       277       -    -277

This patch:

Implement a clean, simple and effective radix-tree iteration routine.

Iterating divided into two phases:
* lookup next chunk in radix-tree leaf node
* iterating through slots in this chunk

Main iterator function radix_tree_next_chunk() returns pointer to first
slot, and stores in the struct radix_tree_iter index of next-to-last slot.
 For tagged-iterating it also constuct bitmask of tags for retunted chunk.
 All additional logic implemented as static-inline functions and macroses.

Also adds radix_tree_find_next_bit() static-inline variant of
find_next_bit() optimized for small constant size arrays, because
find_next_bit() too heavy for searching in an array with one/two long
elements.

[akpm@linux-foundation.org: rework comments a bit]
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Tested-by: NHugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In the case of a child pid namespace, rebooting the system does not really
makes sense.  When the pid namespace is used in conjunction with the other
namespaces in order to create a linux container, the reboot syscall leads
to some problems.

A container can reboot the host.  That can be fixed by dropping the
sys_reboot capability but we are unable to correctly to poweroff/
halt/reboot a container and the container stays stuck at the shutdown time
with the container's init process waiting indefinitively.

After several attempts, no solution from userspace was found to reliabily
handle the shutdown from a container.

This patch propose to make the init process of the child pid namespace to
exit with a signal status set to : SIGINT if the child pid namespace
called "halt/poweroff" and SIGHUP if the child pid namespace called
"reboot".  When the reboot syscall is called and we are not in the initial
pid namespace, we kill the pid namespace for "HALT", "POWEROFF",
"RESTART", and "RESTART2".  Otherwise we return EINVAL.

Returning EINVAL is also an easy way to check if this feature is supported
by the kernel when invoking another 'reboot' option like CAD.

By this way the parent process of the child pid namespace knows if it
rebooted or not and can take the right decision.

Test case:
==========

#include <alloca.h>
#include <stdio.h>
#include <sched.h>
#include <unistd.h>
#include <signal.h>
#include <sys/reboot.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <linux/reboot.h>

static int do_reboot(void *arg)
{
        int *cmd = arg;

        if (reboot(*cmd))
                printf("failed to reboot(%d): %m\n", *cmd);
}

int test_reboot(int cmd, int sig)
{
        long stack_size = 4096;
        void *stack = alloca(stack_size) + stack_size;
        int status;
        pid_t ret;

        ret = clone(do_reboot, stack, CLONE_NEWPID | SIGCHLD, &cmd);
        if (ret < 0) {
                printf("failed to clone: %m\n");
                return -1;
        }

        if (wait(&status) < 0) {
                printf("unexpected wait error: %m\n");
                return -1;
        }

        if (!WIFSIGNALED(status)) {
                printf("child process exited but was not signaled\n");
                return -1;
        }

        if (WTERMSIG(status) != sig) {
                printf("signal termination is not the one expected\n");
                return -1;
        }

        return 0;
}

int main(int argc, char *argv[])
{
        int status;

        status = test_reboot(LINUX_REBOOT_CMD_RESTART, SIGHUP);
        if (status < 0)
                return 1;
        printf("reboot(LINUX_REBOOT_CMD_RESTART) succeed\n");

        status = test_reboot(LINUX_REBOOT_CMD_RESTART2, SIGHUP);
        if (status < 0)
                return 1;
        printf("reboot(LINUX_REBOOT_CMD_RESTART2) succeed\n");

        status = test_reboot(LINUX_REBOOT_CMD_HALT, SIGINT);
        if (status < 0)
                return 1;
        printf("reboot(LINUX_REBOOT_CMD_HALT) succeed\n");

        status = test_reboot(LINUX_REBOOT_CMD_POWER_OFF, SIGINT);
        if (status < 0)
                return 1;
        printf("reboot(LINUX_REBOOT_CMD_POWERR_OFF) succeed\n");

        status = test_reboot(LINUX_REBOOT_CMD_CAD_ON, -1);
        if (status >= 0) {
                printf("reboot(LINUX_REBOOT_CMD_CAD_ON) should have failed\n");
                return 1;
        }
        printf("reboot(LINUX_REBOOT_CMD_CAD_ON) has failed as expected\n");

        return 0;
}

[akpm@linux-foundation.org: tweak and add comments]
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: NDaniel Lezcano <daniel.lezcano@free.fr>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Tested-by: NSerge Hallyn <serge.hallyn@canonical.com>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__any_online_cpu() is not optimal and also unnecessary.  So, replace its
use by faster cpumask_* operations.
Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
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>

Add the on_each_cpu_cond() function that wraps on_each_cpu_mask() and
calculates the cpumask of cpus to IPI by calling a function supplied as a
parameter in order to determine whether to IPI each specific cpu.

The function works around allocation failure of cpumask variable in
CONFIG_CPUMASK_OFFSTACK=y by itereating over cpus sending an IPI a time
via smp_call_function_single().

The function is useful since it allows to seperate the specific code that
decided in each case whether to IPI a specific cpu for a specific request
from the common boilerplate code of handling creating the mask, handling
failures etc.

[akpm@linux-foundation.org: s/gfpflags/gfp_flags/]
[akpm@linux-foundation.org: avoid double-evaluation of `info' (per Michal), parenthesise evaluation of `cond_func']
[akpm@linux-foundation.org: s/CPU/CPUs, use all 80 cols in comment]
Signed-off-by: NGilad Ben-Yossef <gilad@benyossef.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Avi Kivity <avi@redhat.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.org>
Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
Cc: Milton Miller <miltonm@bga.com>
Reviewed-by: N"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have lots of infrastructure in place to partition multi-core systems
such that we have a group of CPUs that are dedicated to specific task:
cgroups, scheduler and interrupt affinity, and cpuisol= boot parameter.
Still, kernel code will at times interrupt all CPUs in the system via IPIs
for various needs.  These IPIs are useful and cannot be avoided
altogether, but in certain cases it is possible to interrupt only specific
CPUs that have useful work to do and not the entire system.

This patch set, inspired by discussions with Peter Zijlstra and Frederic
Weisbecker when testing the nohz task patch set, is a first stab at trying
to explore doing this by locating the places where such global IPI calls
are being made and turning the global IPI into an IPI for a specific group
of CPUs.  The purpose of the patch set is to get feedback if this is the
right way to go for dealing with this issue and indeed, if the issue is
even worth dealing with at all.  Based on the feedback from this patch set
I plan to offer further patches that address similar issue in other code
paths.

This patch creates an on_each_cpu_mask() and on_each_cpu_cond()
infrastructure API (the former derived from existing arch specific
versions in Tile and Arm) and uses them to turn several global IPI
invocation to per CPU group invocations.

Core kernel:

on_each_cpu_mask() calls a function on processors specified by cpumask,
which may or may not include the local processor.

You must not call this function with disabled interrupts or from a
hardware interrupt handler or from a bottom half handler.

arch/arm:

Note that the generic version is a little different then the Arm one:

1. It has the mask as first parameter
2. It calls the function on the calling CPU with interrupts disabled,
   but this should be OK since the function is called on the other CPUs
   with interrupts disabled anyway.

arch/tile:

The API is the same as the tile private one, but the generic version
also calls the function on the with interrupts disabled in UP case

This is OK since the function is called on the other CPUs
with interrupts disabled.
Signed-off-by: NGilad Ben-Yossef <gilad@benyossef.com>
Reviewed-by: NChristoph Lameter <cl@linux.com>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Avi Kivity <avi@redhat.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.org>
Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
Cc: Milton Miller <miltonm@bga.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Most system calls taking flags first check that the flags passed in are
valid, and that helps userspace to detect when new flags are supported.

But swapon never did so: start checking now, to help if we ever want to
support more swap_flags in future.

It's difficult to get stray bits set in an int, and swapon is not widely
used, so this is most unlikely to break any userspace; but we can just
revert if it turns out to do so.
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Holepunching filesystems ext4 and xfs are using truncate_inode_pages_range
but forgetting to unmap pages first (ocfs2 remembers).  This is not really
a bug, since races already require truncate_inode_page() to handle that
case once the page is locked; but it can be very inefficient if the file
being punched happens to be mapped into many vmas.

Provide a drop-in replacement truncate_pagecache_range() which does the
unmapping pass first, handling the awkward mismatch between arguments to
truncate_inode_pages_range() and arguments to unmap_mapping_range().

Note that holepunching does not unmap privately COWed pages in the range:
POSIX requires that we do so when truncating, but it's hard to justify,
difficult to implement without an i_size cutoff, and no filesystem is
attempting to implement it.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: Alex Elder <elder@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Delete all instances of asm/system.h as they should be redundant by this
point.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`
Signed-off-by: NDavid Howells <dhowells@redhat.com>

asm/system.h is a cause of circular dependency problems because it contains
commonly used primitive stuff like barrier definitions and uncommonly used
stuff like switch_to() that might require MMU definitions.

asm/system.h has been disintegrated by this point on all arches into the
following common segments:

 (1) asm/barrier.h

     Moved memory barrier definitions here.

 (2) asm/cmpxchg.h

     Moved xchg() and cmpxchg() here.  #included in asm/atomic.h.

 (3) asm/bug.h

     Moved die() and similar here.

 (4) asm/exec.h

     Moved arch_align_stack() here.

 (5) asm/elf.h

     Moved AT_VECTOR_SIZE_ARCH here.

 (6) asm/switch_to.h

     Moved switch_to() here.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Move all declarations of free_initmem() to linux/mm.h so that there's only one
and it's used by everything.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: linux-c6x-dev@linux-c6x.org
cc: microblaze-uclinux@itee.uq.edu.au
cc: linux-sh@vger.kernel.org
cc: sparclinux@vger.kernel.org
cc: x86@kernel.org
cc: linux-mm@kvack.org