Revert "mm: panic on the first bad page table entry access"

This reverts commit 215a2c3137b906afd66c93eb9fb3479a1f06e1c9.

Change-Id: Ica69d573fe0e2fab19ddfc3979513bdedb69c717
sync: Fix a race condition between release_obj and print_obj

Before this change, a timeline would only be removed from the timeline
list *after* the sync driver had its release_obj() called. However, the
driver's release_obj() may free resources needed by print_obj().

Although the timeline list is locked when print_obj() is called, it is
not locked when release_obj() is called. If one CPU was in print_obj()
when another was in release_obj(), the print_obj() may make unsafe
accesses.

It is not actually necessary to hold the timeline list lock when calling
release_obj() if the call is made after the timeline is unlinked from
the list, since there is no possibility another thread could be in --
or enter -- print_obj() for that timeline.

This change moves the release_obj() call to after the timeline is
unlinked, preventing the above race from occurring.

Signed-off-by: Alistair Strachan <alistair.strachan@imgtec.com>

Change-Id: I563347e163ac4ef19c2f5930c3ec10e61f5f5d44
sync: signal pt before sync_timeline object gets destroyed

There is a race condition

Assume we have *one* sync_fence object, with *one* sync_pt
which belongs to *one* sync_timeline, given this condition,
sync_timeline->kref will have two counts, one for sync_timeline
(implicit) and another for sync_pt.

Assume following is the situation on CPU

Theead-1 : (Thread which calls sync_timeline_destroy())
  -> (some function calls)
   -> sync_timeline_destory()
    -> sync_timeline_signal() (CPU is inside this
function after putting reference to sync_timeline)

At this time Thread-2 comes and does following

Thread-2 : (fclose on fence fd)
> sync_fence_release() -> because of fclose() on fence object
 -> sync_fence_free()
  -> sync_pt_free()
   -> kref_put(&pt->parent->kref, sync_timeline_free);
    -> sync_timeline_free() (CPU is inside this because
this time kref will be zero after _put)

Thread-2 will free sync_timeline object before Thread-1
has finished its work inside sync_timeline_signal.

With this change we signals all sync_pt before putting
reference to sync_timeline object.

Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>
Signed-off-by: Rom Lemarchand <romlem@google.com>

Change-Id: Ic680e4d0bbef1c46bcb7cfba693395645241d203
cpuidle: make a single register function for all

The usual scheme to initialize a cpuidle driver on a SMP is:

	cpuidle_register_driver(drv);
	for_each_possible_cpu(cpu) {
		device = &per_cpu(cpuidle_dev, cpu);
		cpuidle_register_device(device);
	}

This code is duplicated in each cpuidle driver.

On UP systems, it is done this way:

	cpuidle_register_driver(drv);
	device = &per_cpu(cpuidle_dev, cpu);
	cpuidle_register_device(device);

On UP, the macro 'for_each_cpu' does one iteration:

        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)

Hence, the initialization loop is the same for UP than SMP.

Beside, we saw different bugs / mis-initialization / return code unchecked in
the different drivers, the code is duplicated including bugs. After fixing all
these ones, it appears the initialization pattern is the same for everyone.

Please note, some drivers are doing dev->state_count = drv->state_count. This is
not necessary because it is done by the cpuidle_enable_device function in the
cpuidle framework. This is true, until you have the same states for all your
devices. Otherwise, the 'low level' API should be used instead with the specific
initialization for the driver.

Let's add a wrapper function doing this initialization with a cpumask parameter
for the coupled idle states and use it for all the drivers.

That will save a lot of LOC, consolidate the code, and the modifications in the
future could be done in a single place. Another benefit is the consolidation of
the cpuidle_device variable which is now in the cpuidle framework and no longer
spread accross the different arch specific drivers.

Change-Id: I8f75188d5770871620f758c2973b74384ac570d5
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Karthik Parsha <kparsha@codeaurora.org>
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
jbd2: don't BUG but return ENOSPC if a handle runs out of space

commit f6c07cad081ba222d63623d913aafba5586c1d2c upstream.

If a handle runs out of space, we currently stop the kernel with a BUG
in jbd2_journal_dirty_metadata().  This makes it hard to figure out
what might be going on.  So return an error of ENOSPC, so we can let
the file system layer figure out what is going on, to make it more
likely we can get useful debugging information).  This should make it
easier to debug problems such as the one which was reported by:

    https://bugzilla.kernel.org/show_bug.cgi?id=44731

The only two callers of this function are ext4_handle_dirty_metadata()
and ocfs2_journal_dirty().  The ocfs2 function will trigger a
BUG_ON(), which means there will be no change in behavior.  The ext4
function will call ext4_error_inode() which will print the useful
debugging information and then handle the situation using ext4's error
handling mechanisms (i.e., which might mean halting the kernel or
remounting the file system read-only).

Also, since both file systems already call WARN_ON(), drop the WARN_ON
from jbd2_journal_dirty_metadata() to avoid two stack traces from
being displayed.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: ocfs2-devel@oss.oracle.com
Acked-by: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change-Id: I31a547fab628c7a7fd515516dbc83cda23560b4e
ext4: fix memory leak in xattr

If we take the 2nd retry path in ext4_expand_extra_isize_ea, we
potentionally return from the function without having freed these
allocations.  If we don't do the return, we over-write the previous
allocation pointers, so we leak either way.

Spotted with Coverity.

[ Fixed by tytso to set is and bs to NULL after freeing these
  pointers, in case in the retry loop we later end up triggering an
  error causing a jump to cleanup, at which point we could have a double
  free bug. -- Ted ]

Change-Id: I49b8ca41a6c6d44b563eb23306870258a3affd3b
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Cc: stable@vger.kernel.org
Git-commit: 6e4ea8e33b2057b85d75175dd89b93f5e26de3bc
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>
writeback: fix race that cause writeback hung

There is a race between mark inode dirty and writeback thread, see the
following scenario.  In this case, writeback thread will not run though
there is dirty_io.

__mark_inode_dirty()                                          bdi_writeback_workfn()
	...                                                       	...
	spin_lock(&inode->i_lock);
	...
	if (bdi_cap_writeback_dirty(bdi)) {
	    <<< assume wb has dirty_io, so wakeup_bdi is false.
	    <<< the following inode_dirty also have wakeup_bdi false.
	    if (!wb_has_dirty_io(&bdi->wb))
		    wakeup_bdi = true;
	}
	spin_unlock(&inode->i_lock);
	                                                            <<< assume last dirty_io is removed here.
	                                                            pages_written = wb_do_writeback(wb);
	                                                            ...
	                                                            <<< work_list empty and wb has no dirty_io,
	                                                            <<< delayed_work will not be queued.
	                                                            if (!list_empty(&bdi->work_list) ||
	                                                                (wb_has_dirty_io(wb) && dirty_writeback_interval))
	                                                                queue_delayed_work(bdi_wq, &wb->dwork,
	                                                                    msecs_to_jiffies(dirty_writeback_interval * 10));
	spin_lock(&bdi->wb.list_lock);
	inode->dirtied_when = jiffies;
	<<< new dirty_io is added.
	list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
	spin_unlock(&bdi->wb.list_lock);

	<<< though there is dirty_io, but wakeup_bdi is false,
	<<< so writeback thread will not be waked up and
	<<< the new dirty_io will not be flushed.
	if (wakeup_bdi)
	    bdi_wakeup_thread_delayed(bdi);

Writeback will run until there is a new flush work queued.  This may cause
a lot of dirty pages stay in memory for a long time.

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>

Change-Id: I973fcba5381881a003a035ffff48f64348660079
ext4: speed up truncate/unlink by not using bforget() unless needed

Do not iterate over data blocks scanning for bh's to forget as they're
never exist. This improves time taken by unlink / truncate syscall.
Tested by continuously truncating file that is being written by dd.
Another test is rm -rf of linux tree while tar unpacks it. With
ordered data mode condition unlikely(!tbh) was always met in
ext4_free_blocks. With journal data mode tbh was found only few times,
so optimisation is also possible.

Unlinking fallocated 60G file after doing sync && echo 3 >
/proc/sys/vm/drop_caches && time rm --help

X86 before (linux 3.6-rc4):
real    0m2.710s
user    0m0.000s
sys     0m1.530s

X86 after:
real    0m0.644s
user    0m0.003s
sys     0m0.060s

MIPS before (linux 2.6.37):
real    0m 4.93s
user    0m 0.00s
sys     0m 4.61s

MIPS after:
real    0m 0.16s
user    0m 0.00s
sys     0m 0.06s

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrey Sidorov <qrxd43@motorola.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Change-Id: Ie78a945cb82b3892eaf88701f2dc3b7726104fb5
vfs: dcache: fix deadlock in tree traversal

IBM reported a deadlock in select_parent().  This was found to be caused
by taking rename_lock when already locked when restarting the tree
traversal.

There are two cases when the traversal needs to be restarted:

 1) concurrent d_move(); this can only happen when not already locked,
    since taking rename_lock protects against concurrent d_move().

 2) racing with final d_put() on child just at the moment of ascending
    to parent; rename_lock doesn't protect against this rare race, so it
    can happen when already locked.

Because of case 2, we need to be able to handle restarting the traversal
when rename_lock is already held.  This patch fixes all three callers of
try_to_ascend().

IBM reported that the deadlock is gone with this patch.

[ I rewrote the patch to be smaller and just do the "goto again" if the
  lock was already held, but credit goes to Miklos for the real work.
   - Linus ]

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change-Id: If26492e93922133222868ccac85c17601979c902
jbd2: optimize jbd2_journal_force_commit

Current implementation of jbd2_journal_force_commit() is suboptimal because
result in empty and useless commits. But callers just want to force and wait
any unfinished commits. We already have jbd2_journal_force_commit_nested()
which does exactly what we want, except we are guaranteed that we do not hold
journal transaction open.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

Change-Id: I5c041a1898838e880714a913b5a915f105a8dfb9
ARM: Use -mcpu=cortex-a15 when targeting MSM Krait CPUs

Enable compiler optimizations specific to the Cortex-A15
processor when targeting MSM Krait CPUs. This is necessary
take advantage of the UDIV/SDIV instructions supported by
these processors. To accomplish this, we need to remove the
-march=armv7-a ISA restriction from the compiler options
because 'cortex-a15' is a superset of 'armv7-a'.

Change-Id: I6215aecc11fb4f77c971de7b84f68649ef234357
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>