linux-stable.git/include/linux, branch linux-3.1.y

memcg: add mem_cgroup_replace_page_cache() to fix LRU issue

2012-01-18T15:31:58+00:00

commit ab936cbcd02072a34b60d268f94440fd5cf1970b upstream.

Commit ef6a3c6311 ("mm: add replace_page_cache_page() function") added a
function replace_page_cache_page().  This function replaces a page in the
radix-tree with a new page.  WHen doing this, memory cgroup needs to fix
up the accounting information.  memcg need to check PCG_USED bit etc.

In some(many?) cases, 'newpage' is on LRU before calling
replace_page_cache().  So, memcg's LRU accounting information should be
fixed, too.

This patch adds mem_cgroup_replace_page_cache() and removes the old hooks.
 In that function, old pages will be unaccounted without touching
res_counter and new page will be accounted to the memcg (of old page).
WHen overwriting pc->mem_cgroup of newpage, take zone->lru_lock and avoid
races with LRU handling.

Background:
  replace_page_cache_page() is called by FUSE code in its splice() handling.
  Here, 'newpage' is replacing oldpage but this newpage is not a newly allocated
  page and may be on LRU. LRU mis-accounting will be critical for memory cgroup
  because rmdir() checks the whole LRU is empty and there is no account leak.
  If a page is on the other LRU than it should be, rmdir() will fail.

This bug was added in March 2011, but no bug report yet.  I guess there
are not many people who use memcg and FUSE at the same time with upstream
kernels.

The result of this bug is that admin cannot destroy a memcg because of
account leak.  So, no panic, no deadlock.  And, even if an active cgroup
exist, umount can succseed.  So no problem at shutdown.

Signed-off-by: KAMEZAWA Hiroyuki 
Acked-by: Johannes Weiner 
Acked-by: Michal Hocko 
Cc: Miklos Szeredi 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

PCI: Fix PCI_EXP_TYPE_RC_EC value

2012-01-18T15:31:56+00:00

commit 1830ea91c20b06608f7cdb2455ce05ba834b3214 upstream.

Spec shows this as 1010b = 0xa

Signed-off-by: Alex Williamson 
Signed-off-by: Jesse Barnes 
Signed-off-by: Greg Kroah-Hartman

NFSv4: include bitmap in nfsv4 get acl data

2012-01-18T15:31:55+00:00

commit bf118a342f10dafe44b14451a1392c3254629a1f upstream.

The NFSv4 bitmap size is unbounded: a server can return an arbitrary
sized bitmap in an FATTR4_WORD0_ACL request.  Replace using the
nfs4_fattr_bitmap_maxsz as a guess to the maximum bitmask returned by a server
with the inclusion of the bitmap (xdr length plus bitmasks) and the acl data
xdr length to the (cached) acl page data.

This is a general solution to commit e5012d1f "NFSv4.1: update
nfs4_fattr_bitmap_maxsz" and fixes hitting a BUG_ON in xdr_shrink_bufhead
when getting ACLs.

Fix a bug in decode_getacl that returned -EINVAL on ACLs > page when getxattr
was called with a NULL buffer, preventing ACL > PAGE_SIZE from being retrieved.

Signed-off-by: Andy Adamson 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

usb: ch9: fix up MaxStreams helper

2012-01-12T19:33:38+00:00

commit 18b7ede5f7ee2092aedcb578d3ac30bd5d4fc23c upstream.

[ removed the dwc3 portion of the patch as it didn't apply to
older kernels - gregkh]

According to USB 3.0 Specification Table 9-22, if
bmAttributes [4:0] are set to zero, it means "no
streams supported", but the way this helper was
defined on Linux, we will *always* have one stream
which might cause several problems.

For example on DWC3, we would tell the controller
endpoint has streams enabled and yet start transfers
with Stream ID set to 0, which would goof up the host
side.

While doing that, convert the macro to an inline
function due to the different checks we now need.

Signed-off-by: Felipe Balbi 
Signed-off-by: Sarah Sharp 
Signed-off-by: Greg Kroah-Hartman

usb: fix number of mapped SG DMA entries

2012-01-12T19:33:35+00:00

commit bc677d5b64644c399cd3db6a905453e611f402ab upstream.

Add a new field num_mapped_sgs to struct urb so that we have a place to
store the number of mapped entries and can also retain the original
value of entries in num_sgs.  Previously, usb_hcd_map_urb_for_dma()
would overwrite this with the number of mapped entries, which would
break dma_unmap_sg() because it requires the original number of entries.

This fixes warnings like the following when using USB storage devices:
 ------------[ cut here ]------------
 WARNING: at lib/dma-debug.c:902 check_unmap+0x4e4/0x695()
 ehci_hcd 0000:00:12.2: DMA-API: device driver frees DMA sg list with different entry count [map count=4] [unmap count=1]
 Modules linked in: ohci_hcd ehci_hcd
 Pid: 0, comm: kworker/0:1 Not tainted 3.2.0-rc2+ #319
 Call Trace:
    [] warn_slowpath_common+0x80/0x98
  [] warn_slowpath_fmt+0x41/0x43
  [] check_unmap+0x4e4/0x695
  [] ? trace_hardirqs_off+0xd/0xf
  [] ? _raw_spin_unlock_irqrestore+0x33/0x50
  [] debug_dma_unmap_sg+0xeb/0x117
  [] usb_hcd_unmap_urb_for_dma+0x71/0x188
  [] unmap_urb_for_dma+0x20/0x22
  [] usb_hcd_giveback_urb+0x5d/0xc0
  [] ehci_urb_done+0xf7/0x10c [ehci_hcd]
  [] qh_completions+0x429/0x4bd [ehci_hcd]
  [] ehci_work+0x95/0x9c0 [ehci_hcd]
  ...
 ---[ end trace f29ac88a5a48c580 ]---
 Mapped at:
  [] debug_dma_map_sg+0x45/0x139
  [] usb_hcd_map_urb_for_dma+0x22e/0x478
  [] usb_hcd_submit_urb+0x63f/0x6fa
  [] usb_submit_urb+0x2c7/0x2de
  [] usb_sg_wait+0x55/0x161

Signed-off-by: Clemens Ladisch 
Signed-off-by: Greg Kroah-Hartman

mfd: Turn on the twl4030-madc MADC clock

2012-01-06T22:17:33+00:00

commit 3d6271f92e98094584fd1e609a9969cd33e61122 upstream.

Without turning the MADC clock on, no MADC conversions occur.

$ cat /sys/class/hwmon/hwmon0/device/in8_input
[   53.428436] twl4030_madc twl4030_madc: conversion timeout!
cat: read error: Resource temporarily unavailable

Signed-off-by: Kyle Manna 
Signed-off-by: Samuel Ortiz 
Signed-off-by: Greg Kroah-Hartman

VFS: Fix race between CPU hotplug and lglocks

2012-01-06T22:17:18+00:00

commit e30e2fdfe56288576ee9e04dbb06b4bd5f282203 upstream.

Currently, the *_global_[un]lock_online() routines are not at all synchronized
with CPU hotplug. Soft-lockups detected as a consequence of this race was
reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng
for finding out that the root-cause of this issue is the race condition
between br_write_[un]lock() and CPU hotplug, which results in the lock states
getting messed up).

Fixing this race by just adding {get,put}_online_cpus() at appropriate places
in *_global_[un]lock_online() is not a good option, because, then suddenly
br_write_[un]lock() would become blocking, whereas they have been kept as
non-blocking all this time, and we would want to keep them that way.

So, overall, we want to ensure 3 things:
1. br_write_lock() and br_write_unlock() must remain as non-blocking.
2. The corresponding lock and unlock of the per-cpu spinlocks must not happen
   for different sets of CPUs.
3. Either prevent any new CPU online operation in between this lock-unlock, or
   ensure that the newly onlined CPU does not proceed with its corresponding
   per-cpu spinlock unlocked.

To achieve all this:
(a) We introduce a new spinlock that is taken by the *_global_lock_online()
    routine and released by the *_global_unlock_online() routine.
(b) We register a callback for CPU hotplug notifications, and this callback
    takes the same spinlock as above.
(c) We maintain a bitmap which is close to the cpu_online_mask, and once it is
    initialized in the lock_init() code, all future updates to it are done in
    the callback, under the above spinlock.
(d) The above bitmap is used (instead of cpu_online_mask) while locking and
    unlocking the per-cpu locks.

The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the
br_write_lock-unlock sequence is in progress, the callback keeps spinning,
thus preventing the CPU online operation till the lock-unlock sequence is
complete. This takes care of requirement (3).

The bitmap that we maintain remains unmodified throughout the lock-unlock
sequence, since all updates to it are managed by the callback, which takes
the same spinlock as the one taken by the lock code and released only by the
unlock routine. Combining this with (d) above, satisfies requirement (2).

Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug
operations from racing with br_write_lock-unlock, requirement (1) is also
taken care of.

By the way, it is to be noted that a CPU offline operation can actually run
in parallel with our lock-unlock sequence, because our callback doesn't react
to notifications earlier than CPU_DEAD (in order to maintain our bitmap
properly). And this means, since we use our own bitmap (which is stale, on
purpose) during the lock-unlock sequence, we could end up unlocking the
per-cpu lock of an offline CPU (because we had locked it earlier, when the
CPU was online), in order to satisfy requirement (2). But this is harmless,
though it looks a bit awkward.

Debugged-by: Cong Meng 
Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

block: initialize request_queue's numa node during

2012-01-06T22:16:56+00:00

commit 5151412dd4338b273afdb107c3772528e9e67d92 upstream.

struct request_queue is allocated with __GFP_ZERO so its "node" field is
zero before initialization.  This causes an oops if node 0 is offline in
the page allocator because its zonelists are not initialized.  From Dave
Young's dmesg:

	SRAT: Node 1 PXM 2 0-d0000000
	SRAT: Node 1 PXM 2 100000000-330000000
	SRAT: Node 0 PXM 1 330000000-630000000
	Initmem setup node 1 0000000000000000-000000000affb000
	...
	Built 1 zonelists in Node order, mobility grouping on.
	...
	BUG: unable to handle kernel paging request at 0000000000001c08
	IP: [] __alloc_pages_nodemask+0xb5/0x870

and __alloc_pages_nodemask+0xb5 translates to a NULL pointer on
zonelist->_zonerefs.

The fix is to initialize q->node at the time of allocation so the correct
node is passed to the slab allocator later.

Since blk_init_allocated_queue_node() is no longer needed, merge it with
blk_init_allocated_queue().

[rientjes@google.com: changelog, initializing q->node]
Reported-by: Dave Young 
Signed-off-by: Mike Snitzer 
Signed-off-by: David Rientjes 
Tested-by: Dave Young 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

linux/log2.h: Fix rounddown_pow_of_two(1)

2011-12-21T20:58:30+00:00

commit 13c07b0286d340275f2d97adf085cecda37ede37 upstream.

Exactly like roundup_pow_of_two(1), the rounddown version was buggy for
the case of a compile-time constant '1' argument.  Probably because it
originated from the same code, sharing history with the roundup version
from before the bugfix (for that one, see commit 1a06a52ee1b0: "Fix
roundup_pow_of_two(1)").

However, unlike the roundup version, the fix for rounddown is to just
remove the broken special case entirely.  It's simply not needed - the
generic code

    1UL << ilog2(n)

does the right thing for the constant '1' argment too.  The only reason
roundup needed that special case was because rounding up does so by
subtracting one from the argument (and then adding one to the result)
causing the obvious problems with "ilog2(0)".

But rounddown doesn't do any of that, since ilog2() naturally truncates
(ie "rounds down") to the right rounded down value.  And without the
ilog2(0) case, there's no reason for the special case that had the wrong
value.

tl;dr: rounddown_pow_of_two(1) should be 1, not 0.

Acked-by: Dmitry Torokhov 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

fix apparmor dereferencing potentially freed dentry, sanitize __d_path() API

2011-12-21T20:58:28+00:00

commit 02125a826459a6ad142f8d91c5b6357562f96615 upstream.

__d_path() API is asking for trouble and in case of apparmor d_namespace_path()
getting just that.  The root cause is that when __d_path() misses the root
it had been told to look for, it stores the location of the most remote ancestor
in *root.  Without grabbing references.  Sure, at the moment of call it had
been pinned down by what we have in *path.  And if we raced with umount -l, we
could have very well stopped at vfsmount/dentry that got freed as soon as
prepend_path() dropped vfsmount_lock.

It is safe to compare these pointers with pre-existing (and known to be still
alive) vfsmount and dentry, as long as all we are asking is "is it the same
address?".  Dereferencing is not safe and apparmor ended up stepping into
that.  d_namespace_path() really wants to examine the place where we stopped,
even if it's not connected to our namespace.  As the result, it looked
at ->d_sb->s_magic of a dentry that might've been already freed by that point.
All other callers had been careful enough to avoid that, but it's really
a bad interface - it invites that kind of trouble.

The fix is fairly straightforward, even though it's bigger than I'd like:
	* prepend_path() root argument becomes const.
	* __d_path() is never called with NULL/NULL root.  It was a kludge
to start with.  Instead, we have an explicit function - d_absolute_root().
Same as __d_path(), except that it doesn't get root passed and stops where
it stops.  apparmor and tomoyo are using it.
	* __d_path() returns NULL on path outside of root.  The main
caller is show_mountinfo() and that's precisely what we pass root for - to
skip those outside chroot jail.  Those who don't want that can (and do)
use d_path().
	* __d_path() root argument becomes const.  Everyone agrees, I hope.
	* apparmor does *NOT* try to use __d_path() or any of its variants
when it sees that path->mnt is an internal vfsmount.  In that case it's
definitely not mounted anywhere and dentry_path() is exactly what we want
there.  Handling of sysctl()-triggered weirdness is moved to that place.
	* if apparmor is asked to do pathname relative to chroot jail
and __d_path() tells it we it's not in that jail, the sucker just calls
d_absolute_path() instead.  That's the other remaining caller of __d_path(),
BTW.
        * seq_path_root() does _NOT_ return -ENAMETOOLONG (it's stupid anyway -
the normal seq_file logics will take care of growing the buffer and redoing
the call of ->show() just fine).  However, if it gets path not reachable
from root, it returns SEQ_SKIP.  The only caller adjusted (i.e. stopped
ignoring the return value as it used to do).

Reviewed-by: John Johansen 
ACKed-by: John Johansen 
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman