Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NDavid Airlie <airlied@linux.ie>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.

* drm_ctxbitmap_next() error handling in drm_addctx() seems broken.
  drm_ctxbitmap_next() return -errno on failure not -1.

[artem.savkov@gmail.com: missing idr_preload_end in drm_gem_flink_ioctl]
[jslaby@suse.cz: fix drm_gem_flink_ioctl() return value]
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NDavid Airlie <airlied@linux.ie>
Signed-off-by: NArtem Savkov <artem.savkov@gmail.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.

v2: Stefan pointed out that add_client_resource() may be called from
    non-process context.  Preload iff @gfp_mask contains __GFP_WAIT.
    Also updated to include minor upper limit check.

[tim.gardner@canonical.com: fix accidentally orphaned 'minor'[
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NTim Gardner <tim.gardner@canonical.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fw_device_init() didn't check whether the allocated minor number isn't
too large.  Fail if it goes overflows MINORBITS.
Signed-off-by: NTejun Heo <tj@kernel.org>
Suggested-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Dan Williams <djbw@fb.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Cc: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.  The existing code looks
buggy to me - ID 0 is treated as no-ID but allocation specifies 0 as
lower limit and there's no error handling after partial success.  This
conversion keeps the bugs unchanged.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NChas Williams <chas@cmf.nrl.navy.mil>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.  Both bsg and genhd
protect idr w/ mutex making preloading unnecessary.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr allocation in blk_alloc_devt() wasn't synchronized against lookup
and removal, and its limit check was off by one - 1 << MINORBITS is
the number of minors allowed, not the maximum allowed minor.

Add locking and rename MAX_EXT_DEVT to NR_EXT_DEVT and fix limit
checking.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NJens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current idr interface is very cumbersome.

* For all allocations, two function calls - idr_pre_get() and
  idr_get_new*() - should be made.

* idr_pre_get() doesn't guarantee that the following idr_get_new*()
  will not fail from memory shortage.  If idr_get_new*() returns
  -EAGAIN, the caller is expected to retry pre_get and allocation.

* idr_get_new*() can't enforce upper limit.  Upper limit can only be
  enforced by allocating and then freeing if above limit.

* idr_layer buffer is unnecessarily per-idr.  Each idr ends up keeping
  around MAX_IDR_FREE idr_layers.  The memory consumed per idr is
  under two pages but it makes it difficult to make idr_layer larger.

This patch implements the following new set of allocation functions.

* idr_preload[_end]() - Similar to radix preload but doesn't fail.
  The first idr_alloc() inside preload section can be treated as if it
  were called with @gfp_mask used for idr_preload().

* idr_alloc() - Allocate an ID w/ lower and upper limits.  Takes
  @gfp_flags and can be used w/o preloading.  When used inside
  preloaded section, the allocation mask of preloading can be assumed.

If idr_alloc() can be called from a context which allows sufficiently
relaxed @gfp_mask, it can be used by itself.  If, for example,
idr_alloc() is called inside spinlock protected region, preloading can
be used like the following.

	idr_preload(GFP_KERNEL);
	spin_lock(lock);

	id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT);

	spin_unlock(lock);
	idr_preload_end();
	if (id < 0)
		error;

which is much simpler and less error-prone than idr_pre_get and
idr_get_new*() loop.

The new interface uses per-pcu idr_layer buffer and thus the number of
idr's in the system doesn't affect the amount of memory used for
preloading.

idr_layer_alloc() is introduced to handle idr_layer allocations for
both old and new ID allocation paths.  This is a bit hairy now but the
new interface is expected to replace the old and the internal
implementation eventually will become simpler.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move slot filling to idr_fill_slot() from idr_get_new_above_int() and
make idr_get_new_above() directly call it.  idr_get_new_above_int() is
no longer needed and removed.

This will be used to implement a new ID allocation interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr uses -1, IDR_NEED_TO_GROW and IDR_NOMORE_SPACE to communicate
exception conditions internally.  The return value is later translated
to errno values using _idr_rc_to_errno().

This is confusing.  Drop the custom ones and consistently use -EAGAIN
for "tree needs to grow", -ENOMEM for "need more memory" and -ENOSPC for
"ran out of ID space".

Due to the weird memory preloading mechanism, [ra]_get_new*() return
-EAGAIN on memory shortage, so we need to substitute -ENOMEM w/
-EAGAIN on those interface functions.  They'll eventually be cleaned
up and the translations will go away.

This patch doesn't introduce any functional changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* Move idr_for_each_entry() definition next to other idr related
  definitions.

* Make id[r|a]_get_new() inline wrappers of id[r|a]_get_new_above().

This changes the implementation of idr_get_new() but the new
implementation is trivial.  This patch doesn't introduce any
functional change.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* Tab align fields like a normal person.

* Drop the unnecessary 0 inits from IDR_INIT().

This patch is purely cosmetic.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There was only one legitimate use of idr_remove_all() and a lot more of
incorrect uses (or lack of it).  Now that idr_destroy() implies
idr_remove_all() and all the in-kernel users updated not to use it,
there's no reason to keep it around.  Mark it deprecated so that we can
later unexport it.

idr_remove_all() is made an inline function calling __idr_remove_all()
to avoid triggering deprecated warning on EXPORT_SYMBOL().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Eric Paris <eparis@parisplace.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop reference to idr_remove_all().  Note that the code
wasn't completely correct before because idr_remove() on all entries
doesn't necessarily release all idr_layers which could lead to memory
leak.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.

The conversion isn't completely trivial for recover_idr_clear() as it's
the only place in kernel which makes legitimate use of idr_remove_all()
w/o idr_destroy().  Replace it with idr_remove() call inside
idr_for_each_entry() loop.  It goes on top so that it matches the
operation order in recover_idr_del().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Cc: David Teigland <teigland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert recover_idr_clear() to use idr_for_each_entry() instead of
idr_for_each().  It's somewhat less efficient this way but it shouldn't
matter in an error path.  This is to help with deprecation of
idr_remove_all().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Cc: David Teigland <teigland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.

* drm_ctxbitmap_cleanup() was calling idr_remove_all() but forgetting
  idr_destroy() thus leaking all buffered free idr_layers.  Replace it
  with idr_destroy().
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NDavid Airlie <airlied@linux.ie>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop its usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr is silly in quite a few ways, one of which is how it's supposed to
be destroyed - idr_destroy() doesn't release IDs and doesn't even whine
if the idr isn't empty.  If the caller forgets idr_remove_all(), it
simply leaks memory.

Even ida gets this wrong and leaks memory on destruction.  There is
absoltely no reason not to call idr_remove_all() from idr_destroy().
Nobody is abusing idr_destroy() for shrinking free layer buffer and
continues to use idr after idr_destroy(), so it's safe to do remove_all
from destroy.

In the whole kernel, there is only one place where idr_remove_all() is
legitimiately used without following idr_destroy() while there are quite
a few places where the caller forgets either idr_remove_all() or
idr_destroy() leaking memory.

This patch makes idr_destroy() call idr_destroy_all() and updates the
function description accordingly.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The iteration logic of idr_get_next() is borrowed mostly verbatim from
idr_for_each().  It walks down the tree looking for the slot matching
the current ID.  If the matching slot is not found, the ID is
incremented by the distance of single slot at the given level and
repeats.

The implementation assumes that during the whole iteration id is aligned
to the layer boundaries of the level closest to the leaf, which is true
for all iterations starting from zero or an existing element and thus is
fine for idr_for_each().

However, idr_get_next() may be given any point and if the starting id
hits in the middle of a non-existent layer, increment to the next layer
will end up skipping the same offset into it.  For example, an IDR with
IDs filled between [64, 127] would look like the following.

          [  0  64 ... ]
       /----/   |
       |        |
      NULL    [ 64 ... 127 ]

If idr_get_next() is called with 63 as the starting point, it will try
to follow down the pointer from 0.  As it is NULL, it will then try to
proceed to the next slot in the same level by adding the slot distance
at that level which is 64 - making the next try 127.  It goes around the
loop and finds and returns 127 skipping [64, 126].

Note that this bug also triggers in idr_for_each_entry() loop which
deletes during iteration as deletions can make layers go away leaving
the iteration with unaligned ID into missing layers.

Fix it by ensuring proceeding to the next slot doesn't carry over the
unaligned offset - ie.  use round_up(id + 1, slot_distance) instead of
id += slot_distance.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NDavid Teigland <teigland@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While adding and removing a lot of disks disks and partitions this
sometimes shows up:

  WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xc9/0x130() (Not tainted)
  Hardware name:
  sysfs: cannot create duplicate filename '/dev/block/259:751'
  Modules linked in: raid1 autofs4 bnx2fc cnic uio fcoe libfcoe libfc 8021q scsi_transport_fc scsi_tgt garp stp llc sunrpc cpufreq_ondemand powernow_k8 freq_table mperf ipv6 dm_mirror dm_region_hash dm_log power_meter microcode dcdbas serio_raw amd64_edac_mod edac_core edac_mce_amd i2c_piix4 i2c_core k10temp bnx2 sg ixgbe dca mdio ext4 mbcache jbd2 dm_round_robin sr_mod cdrom sd_mod crc_t10dif ata_generic pata_acpi pata_atiixp ahci mptsas mptscsih mptbase scsi_transport_sas dm_multipath dm_mod [last unloaded: scsi_wait_scan]
  Pid: 44103, comm: async/16 Not tainted 2.6.32-195.el6.x86_64 #1
  Call Trace:
    warn_slowpath_common+0x87/0xc0
    warn_slowpath_fmt+0x46/0x50
    sysfs_add_one+0xc9/0x130
    sysfs_do_create_link+0x12b/0x170
    sysfs_create_link+0x13/0x20
    device_add+0x317/0x650
    idr_get_new+0x13/0x50
    add_partition+0x21c/0x390
    rescan_partitions+0x32b/0x470
    sd_open+0x81/0x1f0 [sd_mod]
    __blkdev_get+0x1b6/0x3c0
    blkdev_get+0x10/0x20
    register_disk+0x155/0x170
    add_disk+0xa6/0x160
    sd_probe_async+0x13b/0x210 [sd_mod]
    add_wait_queue+0x46/0x60
    async_thread+0x102/0x250
    default_wake_function+0x0/0x20
    async_thread+0x0/0x250
    kthread+0x96/0xa0
    child_rip+0xa/0x20
    kthread+0x0/0xa0
    child_rip+0x0/0x20

This most likely happens because dev_t is freed while the number is
still used and idr_get_new() is not protected on every use.  The fix
adds a mutex where it wasn't before and moves the dev_t free function so
it is called after device del.
Signed-off-by: NTomas Henzl <thenzl@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Though there is no error if we free a NULL pointer, I think we could
avoid this behaviour.  Change the code a little in kimage_crash_alloc()
could avoid this kind of unnecessary free.
Signed-off-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Reviewed-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If kimage_normal_alloc() fails to alloc pages for image->swap_page, it
should call kimage_free_page_list() to free allocated pages in
image->control_pages list before it frees image.
Signed-off-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Reviewed-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If kimage_normal_alloc() fails to initialize an allocated kimage, it will
free the image but would still set 'rimage', as a result kexec_load will
try to free it again.

This would explode as part of the freeing process is accessing internal
members which point to uninitialized memory.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch exports a PG_hwpoison into vmcoreinfo when
CONFIG_MEMORY_FAILURE is defined.  "makedumpfile" needs to read
information of memory, such as 'mem_section', 'zone', 'pageflags' from
vmcore.

We introduce a function into "makedumpfile" to exclude hwpoison page from
vmcore dump.  In order to introduce this function, PG_hwpoison flag have
to export into vmcoreinfo.
Signed-off-by: NMitsuhiro Tanino <mitsuhiro.tanino.gm@hitachi.com>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Cc: Mitsuhiro Tanino <mitsuhiro.tanino.gm@hitachi.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

hole_end has been checked to make sure it is <= crash_res.end in the while
condition check, so the if condition check is duplicate.
Signed-off-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

tAdd adds the values related to buddy system to vmcoreinfo data so that
makedumpfile (dump filtering command) can filter out all free pages with
the new logic.

It's faster than the current logic because it can distinguish free page
by analyzing page structure at the same time as filtering for other
unnecessary pages (e.g.  anonymous page).

OTOH, the current logic has to trace free_list to distinguish free pages
while analyzing page structure to filter out other unnecessary pages.

The new logic uses the fact that buddy page is marked by _mapcount ==
PAGE_BUDDY_MAPCOUNT_VALUE.  But, _mapcount shares its memory with other
fields for SLAB/SLUB when PG_slab is set, so we need to check if PG_slab
is set or not before looking up _mapcount value.  And we can get the
order of buddy system from private field.  To sum it up, the values
below are required for this logic.

Required values:
  - OFFSET(page._mapcount)
  - OFFSET(page.private)
  - NUMBER(PG_slab)
  - NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE)

Changelog from v1 to v2:
1. remove SIZE(pageflags)
  The new logic was changed after I sent v1 patch.
  Accordingly, SIZE(pageflags) has been unnecessary for makedumpfile.

What's makedumpfile:
  makedumpfile creates a small dumpfile by excluding unnecessary pages
  for the analysis. To distinguish unnecessary pages, makedumpfile gets
  the vmcoreinfo data which has the minimum debugging information only
  for dump filtering.
Signed-off-by: NAtsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If new_nsproxy is set we will always call switch_task_namespaces and
then set new_nsproxy back to NULL so the reassignment and fall through
check are redundant
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>