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Tejun Heo [Thu, 13 Feb 2014 11:58:40 +0000 (06:58 -0500)]
cpuset: use css_task_iter_start/next/end() instead of css_scan_tasks()
Now that css_task_iter_start/next_end() supports blocking while
iterating, there's no reason to use css_scan_tasks() which is more
cumbersome to use and scheduled to be removed.
Convert all css_scan_tasks() usages in cpuset to
css_task_iter_start/next/end(). This simplifies the code by removing
heap allocation and callbacks.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Thu, 13 Feb 2014 11:58:40 +0000 (06:58 -0500)]
cgroup: make css_set_lock a rwsem and rename it to css_set_rwsem
Currently there are two ways to walk tasks of a cgroup -
css_task_iter_start/next/end() and css_scan_tasks(). The latter
builds on the former but allows blocking while iterating.
Unfortunately, the way css_scan_tasks() is implemented is rather
nasty, it uses a priority heap of pointers to extract some number of
tasks in task creation order and loops over them invoking the callback
and repeats that until it reaches the end. It requires either
preallocated heap or may fail under memory pressure, while unlikely to
be problematic, the complexity is O(N^2), and in general just nasty.
We're gonna convert all css_scan_users() to
css_task_iter_start/next/end() and remove css_scan_users(). As
css_scan_tasks() users may block, let's convert css_set_lock to a
rwsem so that tasks can block during css_task_iter_*() is in progress.
While this does increase the chance of possible deadlock scenarios,
given the current usage, the probability is relatively low, and even
if that happens, the right thing to do is updating the iteration in
the similar way to css iterators so that it can handle blocking.
Most conversions are trivial; however, task_cgroup_path() now expects
to be called with css_set_rwsem locked instead of locking itself.
This is because the function is called with RCU read lock held and
rwsem locking should nest outside RCU read lock.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Thu, 13 Feb 2014 11:58:39 +0000 (06:58 -0500)]
cgroup: reimplement cgroup_transfer_tasks() without using css_scan_tasks()
Reimplement cgroup_transfer_tasks() so that it repeatedly fetches the
first task in the cgroup and then tranfers it. This achieves the same
result without using css_scan_tasks() which is scheduled to be
removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Thu, 13 Feb 2014 11:58:39 +0000 (06:58 -0500)]
cgroup: implement cgroup_has_tasks() and unexport cgroup_task_count()
cgroup_task_count() read-locks css_set_lock and walks all tasks to
count them and then returns the result. The only thing all the users
want is determining whether the cgroup is empty or not. This patch
implements cgroup_has_tasks() which tests whether cgroup->cset_links
is empty, replaces all cgroup_task_count() usages and unexports it.
Note that the test isn't synchronized. This is the same as before.
The test has always been racy.
This will help planned css_set locking update.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tejun Heo [Thu, 13 Feb 2014 11:58:39 +0000 (06:58 -0500)]
cgroup: relocate cgroup_enable_task_cg_lists()
Move it above so that prototype isn't necessary. Let's also move the
definition of use_task_css_set_links next to it.
This is purely cosmetic.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Thu, 13 Feb 2014 11:58:38 +0000 (06:58 -0500)]
cgroup: enable task_cg_lists on the first cgroup mount
Tasks are not linked on their css_sets until cgroup task iteration is
actually used. This is to avoid incurring overhead on the fork and
exit paths for systems which have cgroup compiled in but don't use it.
This lazy binding also affects the task migration path. It has to be
careful so that it doesn't link tasks to css_sets when task_cg_lists
linking is not enabled yet. Unfortunately, this conditional linking
in the migration path interferes with planned migration updates.
This patch moves the lazy binding a bit earlier, to the first cgroup
mount. It's a clear indication that cgroup is being used on the
system and task_cg_lists linking is highly likely to be enabled soon
anyway through "tasks" and "cgroup.procs" files.
This allows cgroup_task_migrate() to always link @tsk->cg_list. Note
that it may still race with cgroup_post_fork() but who wins that race
is inconsequential.
While at it, make use_task_css_set_links a bool, add sanity checks in
cgroup_enable_task_cg_lists() and css_task_iter_start(), and update
the former so that it's guaranteed and assumes to run only once.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Thu, 13 Feb 2014 11:58:38 +0000 (06:58 -0500)]
cgroup: drop CGRP_ROOT_SUBSYS_BOUND
Before kernfs conversion, due to the way super_block lookup works,
cgroup roots were created and made visible before being fully
initialized. This in turn required a special flag to mark that the
root hasn't been fully initialized so that the destruction path can
tell fully bound ones from half initialized.
That flag is CGRP_ROOT_SUBSYS_BOUND and no longer necessary after the
kernfs conversion as the lookup and creation of new root are atomic
w.r.t. cgroup_mutex. This patch removes the flag and passes the
requests subsystem mask to cgroup_setup_root() so that it can set the
respective mask bits as subsystems are bound.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Thu, 13 Feb 2014 11:58:38 +0000 (06:58 -0500)]
cgroup: disallow xattr, release_agent and name if sane_behavior
Disallow more mount options if sane_behavior. Note that xattr used to
generate warning.
While at it, simplify option check in cgroup_mount() and update
sane_behavior comment in cgroup.h.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Stephen Rothwell [Wed, 12 Feb 2014 21:10:20 +0000 (16:10 -0500)]
sun4M: add include of slab.h for kzalloc
This was being included implicitly via cgroup.h's inclusion of xattr.h
(which has now been removed).
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Tejun Heo [Wed, 12 Feb 2014 14:29:50 +0000 (09:29 -0500)]
cgroup: remove cgroupfs_root->refcnt
Currently, cgroupfs_root and its ->top_cgroup are separated reference
counted and the latter's is ignored. There's no reason to do this
separately. This patch removes cgroupfs_root->refcnt and destroys
cgroupfs_root when the top_cgroup is released.
* cgroup_put() updated to ignore cgroup_is_dead() test for top
cgroups. cgroup_free_fn() updated to handle root destruction when
releasing a top cgroup.
* As root destruction is now bounced through cgroup destruction, it is
asynchronous. Update cgroup_mount() so that it waits for pending
release which is currently implemented using msleep(). Converting
this to proper wait_queue isn't hard but likely unnecessary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Wed, 12 Feb 2014 14:29:50 +0000 (09:29 -0500)]
cgroup: rename cgroupfs_root->number_of_cgroups to ->nr_cgrps and make it atomic_t
root->number_of_cgroups is currently an integer protected with
cgroup_mutex. Except for sanity checks and proc reporting, the only
place it's used is to check whether the root has any child during
remount; however, this is a bit flawed as the counter is not
decremented when the cgroup is unlinked but when it's released,
meaning that there could be an extended period where all cgroups are
removed but remount is still not allowed because some internal objects
are lingering. While not perfect either, it'd be better to use
emptiness test on root->top_cgroup.children.
This patch updates cgroup_remount() to test top_cgroup's children
instead, which makes number_of_cgroups only actual usage statistics
printing in proc implemented in proc_cgroupstats_show(). Let's
shorten its name and make it an atomic_t so that we don't have to
worry about its synchronization. It's purely auxiliary at this point.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Wed, 12 Feb 2014 14:29:50 +0000 (09:29 -0500)]
cgroup: remove cgroup->name
cgroup->name handling became quite complicated over time involving
dedicated struct cgroup_name for RCU protection. Now that cgroup is
on kernfs, we can drop all of it and simply use kernfs_name/path() and
friends. Replace cgroup->name and all related code with kernfs
name/path constructs.
* Reimplement cgroup_name() and cgroup_path() as thin wrappers on top
of kernfs counterparts, which involves semantic changes.
pr_cont_cgroup_name() and pr_cont_cgroup_path() added.
* cgroup->name handling dropped from cgroup_rename().
* All users of cgroup_name/path() updated to the new semantics. Users
which were formatting the string just to printk them are converted
to use pr_cont_cgroup_name/path() instead, which simplifies things
quite a bit. As cgroup_name() no longer requires RCU read lock
around it, RCU lockings which were protecting only cgroup_name() are
removed.
v2: Comment above oom_info_lock updated as suggested by Michal.
v3: dummy_top doesn't have a kn associated and
pr_cont_cgroup_name/path() ended up calling the matching kernfs
functions with NULL kn leading to oops. Test for NULL kn and
print "/" if so. This issue was reported by Fengguang Wu.
v4: Rebased on top of
0ab02ca8f887 ("cgroup: protect modifications to
cgroup_idr with cgroup_mutex").
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tejun Heo [Wed, 12 Feb 2014 14:29:50 +0000 (09:29 -0500)]
cgroup: make cgroup hold onto its kernfs_node
cgroup currently releases its kernfs_node when it gets removed. While
not buggy, this makes cgroup->kn access rules complicated than
necessary and leads to things like get/put protection around
kernfs_remove() in cgroup_destroy_locked(). In addition, we want to
use kernfs_name/path() and friends but also want to be able to
determine a cgroup's name between removal and release.
This patch makes cgroup hold onto its kernfs_node until freed so that
cgroup->kn is always accessible.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Wed, 12 Feb 2014 14:29:49 +0000 (09:29 -0500)]
cgroup: simplify dynamic cftype addition and removal
Dynamic cftype addition and removal using cgroup_add/rm_cftypes()
respectively has been quite hairy due to vfs i_mutex. As i_mutex
nests outside cgroup_mutex, cgroup_mutex has to be released and
regrabbed on each iteration through the hierarchy complicating the
process. Now that i_mutex is no longer in play, it can be simplified.
* Just holding cgroup_tree_mutex is enough. No need to meddle with
cgroup_mutex.
* No reason to play the unlock - relock - check serial_nr dancing.
Everything can be atomically while holding cgroup_tree_mutex.
* cgroup_cfts_prepare() is replaced with direct locking of
cgroup_tree_mutex.
* cgroup_cfts_commit() no longer fiddles with locking. It just
applies the cftypes change to the existing cgroups in the hierarchy.
Renamed to cgroup_cfts_apply().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Wed, 12 Feb 2014 14:29:48 +0000 (09:29 -0500)]
cgroup: remove cftype_set
cftype_set was added primarily to allow registering the same cftype
array more than once for different subsystems. Nobody uses or needs
such thing and it's already broken because each cftype has ->ss
pointer which is initialized during registration.
Let's add list_head ->node to cftype and use the first cftype entry in
the array to link them instead of allocating separate cftype_set.
While at it, trigger WARN if cft seems previously initialized during
registration.
This simplifies cftype handling a bit.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Wed, 12 Feb 2014 14:29:48 +0000 (09:29 -0500)]
cgroup: relocate cgroup_rm_cftypes()
cftype handling is about to be revamped. Relocate cgroup_rm_cftypes()
above cgroup_add_cftypes() in preparation. This is pure relocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Wed, 12 Feb 2014 14:29:48 +0000 (09:29 -0500)]
cgroup: warn if "xattr" is specified with "sane_behavior"
Mount option "xattr" is no longer necessary as it's enabled by default
on kernfs. Warn if "xattr" is specified with "sane_behavior" so that
the option can be removed in the future.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:49 +0000 (11:52 -0500)]
cgroup: convert to kernfs
cgroup filesystem code was derived from the original sysfs
implementation which was heavily intertwined with vfs objects and
locking with the goal of re-using the existing vfs infrastructure.
That experiment turned out rather disastrous and sysfs switched, a
long time ago, to distributed filesystem model where a separate
representation is maintained which is queried by vfs. Unfortunately,
cgroup stuck with the failed experiment all these years and
accumulated even more problems over time.
Locking and object lifetime management being entangled with vfs is
probably the most egregious. vfs is never designed to be misused like
this and cgroup ends up jumping through various convoluted dancing to
make things work. Even then, operations across multiple cgroups can't
be done safely as it'll deadlock with rename locking.
Recently, kernfs is separated out from sysfs so that it can be used by
users other than sysfs. This patch converts cgroup to use kernfs,
which will bring the following benefits.
* Separation from vfs internals. Locking and object lifetime
management is contained in cgroup proper making things a lot
simpler. This removes significant amount of locking convolutions,
hairy object lifetime rules and the restriction on multi-cgroup
operations.
* Can drop a lot of code to implement filesystem interface as most are
provided by kernfs.
* Proper "severing" semantics, which allows controllers to not worry
about lingering file accesses after offline.
While the preceding patches did as much as possible to make the
transition less painful, large part of the conversion has to be one
discrete step making this patch rather large. The rest of the commit
message lists notable changes in different areas.
Overall
-------
* vfs constructs replaced with kernfs ones. cgroup->dentry w/ ->kn,
cgroupfs_root->sb w/ ->kf_root.
* All dentry accessors are removed. Helpers to map from kernfs
constructs are added.
* All vfs plumbing around dentry, inode and bdi removed.
* cgroup_mount() now directly looks for matching root and then
proceeds to create a new one if not found.
Synchronization and object lifetime
-----------------------------------
* vfs inode locking removed. Among other things, this removes the
need for the convolution in cgroup_cfts_commit(). Future patches
will further simplify it.
* vfs refcnting replaced with cgroup internal ones. cgroup->refcnt,
cgroupfs_root->refcnt added. cgroup_put_root() now directly puts
root->refcnt and when it reaches zero proceeds to destroy it thus
merging cgroup_put_root() and the former cgroup_kill_sb().
Simliarly, cgroup_put() now directly schedules cgroup_free_rcu()
when refcnt reaches zero.
* Unlike before, kernfs objects don't hold onto cgroup objects. When
cgroup destroys a kernfs node, all existing operations are drained
and the association is broken immediately. The same for
cgroupfs_roots and mounts.
* All operations which come through kernfs guarantee that the
associated cgroup is and stays valid for the duration of operation;
however, there are two paths which need to find out the associated
cgroup from dentry without going through kernfs -
css_tryget_from_dir() and cgroupstats_build(). For these two,
kernfs_node->priv is RCU managed so that they can dereference it
under RCU read lock.
File and directory handling
---------------------------
* File and directory operations converted to kernfs_ops and
kernfs_syscall_ops.
* xattrs is implicitly supported by kernfs. No need to worry about it
from cgroup. This means that "xattr" mount option is no longer
necessary. A future patch will add a deprecated warning message
when sane_behavior.
* When cftype->max_write_len > PAGE_SIZE, it's necessary to make a
private copy of one of the kernfs_ops to set its atomic_write_len.
cftype->kf_ops is added and cgroup_init/exit_cftypes() are updated
to handle it.
* cftype->lockdep_key added so that kernfs lockdep annotation can be
per cftype.
* Inidividual file entries and open states are now managed by kernfs.
No need to worry about them from cgroup. cfent, cgroup_open_file
and their friends are removed.
* kernfs_nodes are created deactivated and kernfs_activate()
invocations added to places where creation of new nodes are
committed.
* cgroup_rmdir() uses kernfs_[un]break_active_protection() for
self-removal.
v2: - Li pointed out in an earlier patch that specifying "name="
during mount without subsystem specification should succeed if
there's an existing hierarchy with a matching name although it
should fail with -EINVAL if a new hierarchy should be created.
Prior to the conversion, this used by handled by deferring
failure from NULL return from cgroup_root_from_opts(), which was
necessary because root was being created before checking for
existing ones. Note that cgroup_root_from_opts() returned an
ERR_PTR() value for error conditions which require immediate
mount failure.
As we now have separate search and creation steps, deferring
failure from cgroup_root_from_opts() is no longer necessary.
cgroup_root_from_opts() is updated to always return ERR_PTR()
value on failure.
- The logic to match existing roots is updated so that a mount
attempt with a matching name but different subsys_mask are
rejected. This was handled by a separate matching loop under
the comment "Check for name clashes with existing mounts" but
got lost during conversion. Merge the check into the main
search loop.
- Add __rcu __force casting in RCU_INIT_POINTER() in
cgroup_destroy_locked() to avoid the sparse address space
warning reported by kbuild test bot. Maybe we want an explicit
interface to use kn->priv as RCU protected pointer?
v3: Make CONFIG_CGROUPS select CONFIG_KERNFS.
v4: Rebased on top of
0ab02ca8f887 ("cgroup: protect modifications to
cgroup_idr with cgroup_mutex").
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: kbuild test robot fengguang.wu@intel.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:49 +0000 (11:52 -0500)]
cgroup: relocate functions in preparation of kernfs conversion
Relocate cgroup_init/exit_root_id(), cgroup_free_root(),
cgroup_kill_sb() and cgroup_file_name() in preparation of kernfs
conversion.
These are pure relocations to make kernfs conversion easier to follow.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:49 +0000 (11:52 -0500)]
cgroup: misc preps for kernfs conversion
* Un-inline seq_css(). After kernfs conversion, the function will
need to dereference internal data structures.
* Add cgroup_get/put_root() and replace direct super_block->s_active
manipulatinos with them. These will be converted to kernfs_root
refcnting.
* Add cgroup_get/put() and replace dget/put() on cgrp->dentry with
them. These will be converted to kernfs refcnting.
* Update current_css_set_cg_links_read() to use cgroup_name() instead
of reaching into the dentry name. The end result is the same.
These changes don't make functional differences but will make
transition to kernfs easier.
v2: Rebased on top of
0ab02ca8f887 ("cgroup: protect modifications to
cgroup_idr with cgroup_mutex").
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:49 +0000 (11:52 -0500)]
cgroup: introduce cgroup_ino()
mm/memory-failure.c::hwpoison_filter_task() has been reaching into
cgroup to extract the associated ino to be used as a filtering
criterion. This is an implementation detail which shouldn't be
depended upon from outside cgroup proper and is about to change with
the scheduled kernfs conversion.
This patch introduces a proper interface to determine the associated
ino, cgroup_ino(), and updates hwpoison_filter_task() to use it
instead of reaching directly into cgroup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:48 +0000 (11:52 -0500)]
cgroup: introduce cgroup_init/exit_cftypes()
Factor out cft->ss initialization into cgroup_init_cftypes() from
cgroup_add_cftypes() and add cft->ss clearing to cgroup_rm_cftypes()
through cgroup_exit_cftypes().
This doesn't make any meaningful difference now but the two new
functions will be expanded during kernfs transition.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:48 +0000 (11:52 -0500)]
cgroup: update the meaning of cftype->max_write_len
cftype->max_write_len is used to extend the maximum size of writes.
It's interpreted in such a way that the actual maximum size is one
less than the specified value. The default size is defined by
CGROUP_LOCAL_BUFFER_SIZE. Its interpretation is quite confusing - its
value is decremented by 1 and then compared for equality with max
size, which means that the actual default size is
CGROUP_LOCAL_BUFFER_SIZE - 2, which is 62 chars.
There's no point in having a limit that low. Update its definition so
that it means the actual string length sans termination and anything
below PAGE_SIZE-1 is treated as PAGE_SIZE-1.
.max_write_len for "release_agent" is updated to PATH_MAX-1 and
cgroup_release_agent_write() is updated so that the redundant strlen()
check is removed and it uses strlcpy() instead of strcpy().
.max_write_len initializations in blk-throttle.c and cfq-iosched.c are
no longer necessary and removed. The one in cpuset is kept unchanged
as it's an approximated value to begin with.
This will also make transition to kernfs smoother.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:48 +0000 (11:52 -0500)]
cgroup: make cgroup_subsys->base_cftypes use cgroup_add_cftypes()
Currently, cgroup_subsys->base_cftypes registration is different from
dynamic cftypes registartion. Instead of going through
cgroup_add_cftypes(), cgroup_init_subsys() invokes
cgroup_init_cftsets() which makes use of cgroup_subsys->base_cftset
which doesn't involve dynamic allocation.
While avoiding dynamic allocation is somewhat nice, having two
separate paths for cftypes registration is nasty, especially as we're
planning to add more operations during cftypes registration.
This patch drops cgroup_init_cftsets() and cgroup_subsys->base_cftset
and registers base_cftypes using cgroup_add_cftypes(). This is done
as a separate step in cgroup_init() instead of a part of
cgroup_init_subsys(). This is because cgroup_init_subsys() can be
called very early during boot when kmalloc() isn't available yet.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:48 +0000 (11:52 -0500)]
cgroup: update cgroup name handling
Straightforward updates to cgroup name handling in preparation of
kernfs conversion.
* cgroup_alloc_name() is updated to take const char * isntead of
dentry * for name source.
* cgroup name formatting is separated out into cgroup_file_name().
While at it, buffer length protection is added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:48 +0000 (11:52 -0500)]
cgroup: factor out cgroup_setup_root() from cgroup_mount()
Factor out new root initialization into cgroup_setup_root() from
cgroup_mount(). This makes it easier to follow and will ease kernfs
conversion.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:48 +0000 (11:52 -0500)]
cgroup: restructure locking and error handling in cgroup_mount()
cgroup is scheduled to be converted to kernfs. After conversion,
cgroup_mount() won't use the sget() machinery for finding out existing
super_blocks but instead would do that directly. It'll search the
existing cgroupfs_roots for a matching one and create a new one iff a
match doesn't exist. To ease such conversion, this patch restructures
locking and error handling of the function.
cgroup_tree_mutex and cgroup_mutex are grabbed from the get-go and
held until return. For now, due to the way vfs locks nest outside
cgroup mutexes, the two cgroup mutexes are temporarily dropped across
sget() and inode mutex locking, which looks quite ridiculous; however,
these will be removed through kernfs conversion and structuring the
code this way makes the conversion less painful.
The error goto labels are consolidated to two. This looks unwieldy
now but the next patch will factor out creation of new root into a
separate function with accompanying error handling and it'll look a
lot better.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:47 +0000 (11:52 -0500)]
cgroup: release cgroup_mutex over file removals
Now that cftypes and all tree modification operations are protected by
cgroup_tree_mutex, we can drop cgroup_mutex while deleting files and
directories. Drop cgroup_mutex over removals.
This doesn't make any noticeable difference now but is to help kernfs
conversion. In kernfs, removals are sync points which drain in-flight
operations as those operations would grab cgroup_mutex, trying to
delete under cgroup_mutex would deadlock. This can be resolved by
just holding the outer cgroup_tree_mutex which nests outside both
kernfs active reference and cgroup_mutex.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:47 +0000 (11:52 -0500)]
cgroup: introduce cgroup_tree_mutex
Currently cgroup uses combination of inode->i_mutex'es and
cgroup_mutex for synchronization. With the scheduled kernfs
conversion, i_mutex'es will be removed. Unfortunately, just using
cgroup_mutex isn't possible. All kernfs file and syscall operations,
most of which require grabbing cgroup_mutex, will be called with
kernfs active ref held and, if we try to perform kernfs removals under
cgroup_mutex, it can deadlock as kernfs_remove() tries to drain the
target node.
Let's introduce a new outer mutex, cgroup_tree_mutex, which protects
stuff used during hierarchy changing operations - cftypes and all the
operations which may affect the cgroupfs. It also covers css
association and iteration. This allows cgroup_css(), for_each_css()
and other css iterators to be called under cgroup_tree_mutex. The new
mutex will nest above both kernfs's active ref protection and
cgroup_mutex. By protecting tree modifications with a separate outer
mutex, we can get rid of the forementioned deadlock condition.
Actual file additions and removals now require cgroup_tree_mutex
instead of cgroup_mutex. Currently, cgroup_tree_mutex is never used
without cgroup_mutex; however, we'll soon add hierarchy modification
sections which are only protected by cgroup_tree_mutex. In the
future, we might want to make the locking more granular by better
splitting the coverages of the two mutexes. For now, this should do.
v2: Rebased on top of
0ab02ca8f887 ("cgroup: protect modifications to
cgroup_idr with cgroup_mutex").
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Tue, 11 Feb 2014 16:52:47 +0000 (11:52 -0500)]
cgroup: improve css_from_dir() into css_tryget_from_dir()
css_from_dir() returns the matching css (cgroup_subsys_state) given a
dentry and subsystem. The function doesn't pin the css before
returning and requires the caller to be holding RCU read lock or
cgroup_mutex and handling pinning on the caller side.
Given that users of the function are likely to want to pin the
returned css (both existing users do) and that getting and putting
css's are very cheap, there's no reason for the interface to be tricky
like this.
Rename css_from_dir() to css_tryget_from_dir() and make it try to pin
the found css and return it only if pinning succeeded. The callers
are updated so that they no longer do RCU locking and pinning around
the function and just use the returned css.
This will also ease converting cgroup to kernfs.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tejun Heo [Tue, 11 Feb 2014 16:02:59 +0000 (11:02 -0500)]
Merge branch 'cgroup/for-3.14-fixes' into cgroup/for-3.15
Pull for-3.14-fixes to receive
0ab02ca8f887 ("cgroup: protect
modifications to cgroup_idr with cgroup_mutex") prior to kernfs
conversion series to avoid non-trivial conflicts.
Signed-off-by: Tejun Heo <tj@kernel.org>
Li Zefan [Tue, 11 Feb 2014 08:05:46 +0000 (16:05 +0800)]
cgroup: protect modifications to cgroup_idr with cgroup_mutex
Setup cgroupfs like this:
# mount -t cgroup -o cpuacct xxx /cgroup
# mkdir /cgroup/sub1
# mkdir /cgroup/sub2
Then run these two commands:
# for ((; ;)) { mkdir /cgroup/sub1/tmp && rmdir /mnt/sub1/tmp; } &
# for ((; ;)) { mkdir /cgroup/sub2/tmp && rmdir /mnt/sub2/tmp; } &
After seconds you may see this warning:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 25243 at lib/idr.c:527 sub_remove+0x87/0x1b0()
idr_remove called for id=6 which is not allocated.
...
Call Trace:
[<
ffffffff8156063c>] dump_stack+0x7a/0x96
[<
ffffffff810591ac>] warn_slowpath_common+0x8c/0xc0
[<
ffffffff81059296>] warn_slowpath_fmt+0x46/0x50
[<
ffffffff81300aa7>] sub_remove+0x87/0x1b0
[<
ffffffff810f3f02>] ? css_killed_work_fn+0x32/0x1b0
[<
ffffffff81300bf5>] idr_remove+0x25/0xd0
[<
ffffffff810f2bab>] cgroup_destroy_css_killed+0x5b/0xc0
[<
ffffffff810f4000>] css_killed_work_fn+0x130/0x1b0
[<
ffffffff8107cdbc>] process_one_work+0x26c/0x550
[<
ffffffff8107eefe>] worker_thread+0x12e/0x3b0
[<
ffffffff81085f96>] kthread+0xe6/0xf0
[<
ffffffff81570bac>] ret_from_fork+0x7c/0xb0
---[ end trace
2d1577ec10cf80d0 ]---
It's because allocating/removing cgroup ID is not properly synchronized.
The bug was introduced when we converted cgroup_ida to cgroup_idr.
While synchronization is already done inside ida_simple_{get,remove}(),
users are responsible for concurrent calls to idr_{alloc,remove}().
tj: Refreshed on top of
b58c89986a77 ("cgroup: fix error return from
cgroup_create()").
Fixes:
4e96ee8e981b ("cgroup: convert cgroup_ida to cgroup_idr")
Cc: <stable@vger.kernel.org> #3.12+
Reported-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Tejun Heo [Sat, 8 Feb 2014 15:37:44 +0000 (10:37 -0500)]
Merge branch 'driver-core-next' into cgroup/for-3.15
Pending kernfs conversion depends on kernfs improvements in
driver-core-next. Pull it into for-3.15.
Signed-off-by: Tejun Heo <tj@kernel.org>
Tejun Heo [Sat, 8 Feb 2014 15:37:14 +0000 (10:37 -0500)]
Merge branch 'for-3.14-fixes' into for-3.15
Pending kernfs conversion depends on fixes in for-3.14-fixes. Pull it
into for-3.15.
Signed-off-by: Tejun Heo <tj@kernel.org>
Tejun Heo [Sat, 8 Feb 2014 15:37:01 +0000 (10:37 -0500)]
cgroup: remove cgroup_root_mutex
cgroup_root_mutex was added to avoid deadlock involving namespace_sem
via cgroup_show_options(). It added a lot of overhead for the small
purpose of it and, because it's nested under cgroup_mutex, it has very
limited usefulness. The previous patch made cgroup_show_options() not
use cgroup_root_mutex, so nobody needs it anymore. Remove it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Sat, 8 Feb 2014 15:36:58 +0000 (10:36 -0500)]
cgroup: update locking in cgroup_show_options()
cgroup_show_options() grabs cgroup_root_mutex to protect the options
changing while printing; however, holding root_mutex or not doesn't
really make much difference for the function. subsys_mask can be
atomically tested and most of the options aren't allowed to change
anyway once mounted.
The only field which needs synchronization is ->release_agent_path.
This patch introduces a dedicated spinlock to synchronize accesses to
the field and drops cgroup_root_mutex locking from
cgroup_show_options(). The next patch will remove cgroup_root_mutex.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Sat, 8 Feb 2014 15:36:58 +0000 (10:36 -0500)]
cgroup: rename cgroup_subsys->subsys_id to ->id
It's no longer referenced outside cgroup core, so renaming is easy.
Let's rename it for consistency & brevity.
This patch is pure rename.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Sat, 8 Feb 2014 15:36:58 +0000 (10:36 -0500)]
cgroup: clean up cgroup_subsys names and initialization
cgroup_subsys is a bit messier than it needs to be.
* The name of a subsys can be different from its internal identifier
defined in cgroup_subsys.h. Most subsystems use the matching name
but three - cpu, memory and perf_event - use different ones.
* cgroup_subsys_id enums are postfixed with _subsys_id and each
cgroup_subsys is postfixed with _subsys. cgroup.h is widely
included throughout various subsystems, it doesn't and shouldn't
have claim on such generic names which don't have any qualifier
indicating that they belong to cgroup.
* cgroup_subsys->subsys_id should always equal the matching
cgroup_subsys_id enum; however, we require each controller to
initialize it and then BUG if they don't match, which is a bit
silly.
This patch cleans up cgroup_subsys names and initialization by doing
the followings.
* cgroup_subsys_id enums are now postfixed with _cgrp_id, and each
cgroup_subsys with _cgrp_subsys.
* With the above, renaming subsys identifiers to match the userland
visible names doesn't cause any naming conflicts. All non-matching
identifiers are renamed to match the official names.
cpu_cgroup -> cpu
mem_cgroup -> memory
perf -> perf_event
* controllers no longer need to initialize ->subsys_id and ->name.
They're generated in cgroup core and set automatically during boot.
* Redundant cgroup_subsys declarations removed.
* While updating BUG_ON()s in cgroup_init_early(), convert them to
WARN()s. BUGging that early during boot is stupid - the kernel
can't print anything, even through serial console and the trap
handler doesn't even link stack frame properly for back-tracing.
This patch doesn't introduce any behavior changes.
v2: Rebased on top of
fe1217c4f3f7 ("net: net_cls: move cgroupfs
classid handling into core").
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Ingo Molnar <mingo@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Thomas Graf <tgraf@suug.ch>
Tejun Heo [Sat, 8 Feb 2014 15:36:58 +0000 (10:36 -0500)]
cgroup: drop module support
With module supported dropped from net_prio, no controller is using
cgroup module support. None of actual resource controllers can be
built as a module and we aren't gonna add new controllers which don't
control resources. This patch drops module support from cgroup.
* cgroup_[un]load_subsys() and cgroup_subsys->module removed.
* As there's no point in distinguishing IS_BUILTIN() and IS_MODULE(),
cgroup_subsys.h now uses IS_ENABLED() directly.
* enum cgroup_subsys_id now exactly matches the list of enabled
controllers as ordered in cgroup_subsys.h.
* cgroup_subsys[] is now a contiguously occupied array. Size
specification is no longer necessary and dropped.
* for_each_builtin_subsys() is removed and for_each_subsys() is
updated to not require any locking.
* module ref handling is removed from rebind_subsystems().
* Module related comments dropped.
v2: Rebased on top of
fe1217c4f3f7 ("net: net_cls: move cgroupfs
classid handling into core").
v3: Added {} around the if (need_forkexit_callback) block in
cgroup_post_fork() for readability as suggested by Li.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo [Sat, 8 Feb 2014 15:36:58 +0000 (10:36 -0500)]
cgroup: make CONFIG_CGROUP_NET_PRIO bool and drop unnecessary init_netclassid_cgroup()
net_prio is the only cgroup which is allowed to be built as a module.
The savings from allowing one controller to be built as a module are
tiny especially given that cgroup module support itself adds quite a
bit of complexity.
Given that none of other controllers has much chance of being made a
module and that we're unlikely to add new modular controllers, the
added complexity is simply not justifiable.
As a first step to drop cgroup module support, this patch changes the
config option to bool from tristate and drops module related code from
it.
Also, while an earlier commit
fe1217c4f3f7 ("net: net_cls: move
cgroupfs classid handling into core") dropped module support from
net_cls cgroup, it retained a call to cgroup_load_subsys(), which is
noop for built-in controllers. Drop it along with
init_netclassid_cgroup().
v2: Removed modular version of task_netprioidx() in
include/net/netprio_cgroup.h as suggested by Li Zefan.
v3: Rebased on top of
fe1217c4f3f7 ("net: net_cls: move cgroupfs
classid handling into core"). net_cls cgroup part is mostly
dropped except for removal of init_netclassid_cgroup().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Thomas Graf <tgraf@suug.ch>
Tejun Heo [Sat, 8 Feb 2014 15:26:34 +0000 (10:26 -0500)]
cgroup: fix locking in cgroup_cfts_commit()
cgroup_cfts_commit() walks the cgroup hierarchy that the target
subsystem is attached to and tries to apply the file changes. Due to
the convolution with inode locking, it can't keep cgroup_mutex locked
while iterating. It currently holds only RCU read lock around the
actual iteration and then pins the found cgroup using dget().
Unfortunately, this is incorrect. Although the iteration does check
cgroup_is_dead() before invoking dget(), there's nothing which
prevents the dentry from going away inbetween. Note that this is
different from the usual css iterations where css_tryget() is used to
pin the css - css_tryget() tests whether the css can be pinned and
fails if not.
The problem can be solved by simply holding cgroup_mutex instead of
RCU read lock around the iteration, which actually reduces LOC.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: stable@vger.kernel.org
Tejun Heo [Sat, 8 Feb 2014 15:26:33 +0000 (10:26 -0500)]
cgroup: fix error return from cgroup_create()
cgroup_create() was returning 0 after allocation failures. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: stable@vger.kernel.org
Tejun Heo [Sat, 8 Feb 2014 15:26:33 +0000 (10:26 -0500)]
cgroup: fix error return value in cgroup_mount()
When cgroup_mount() fails to allocate an id for the root, it didn't
set ret before jumping to unlock_drop ending up returning 0 after a
failure. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: stable@vger.kernel.org
Tejun Heo [Mon, 3 Feb 2014 19:09:17 +0000 (14:09 -0500)]
kernfs: add CONFIG_KERNFS
As sysfs was kernfs's only user, kernfs has been piggybacking on
CONFIG_SYSFS; however, kernfs is scheduled to grow a new user very
soon. Introduce a separate config option CONFIG_KERNFS which is to be
selected by kernfs users.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Fri, 7 Feb 2014 18:32:07 +0000 (13:32 -0500)]
sysfs, kobject: add sysfs wrapper for kernfs_enable_ns()
Currently, kobject is invoking kernfs_enable_ns() directly. This is
fine now as sysfs and kernfs are enabled and disabled together. If
sysfs is disabled, kernfs_enable_ns() is switched to dummy
implementation too and everything is fine; however, kernfs will soon
have its own config option CONFIG_KERNFS and !SYSFS && KERNFS will be
possible, which can make kobject call into non-dummy
kernfs_enable_ns() with NULL kernfs_node pointers leading to an oops.
Introduce sysfs_enable_ns() which is a wrapper around
kernfs_enable_ns() so that it can be made a noop depending only on
CONFIG_SYSFS regardless of the planned CONFIG_KERNFS.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Fri, 7 Feb 2014 18:32:07 +0000 (13:32 -0500)]
kernfs: implement kernfs_get_parent(), kernfs_name/path() and friends
kernfs_node->parent and ->name are currently marked as "published"
indicating that kernfs users may access them directly; however, those
fields may get updated by kernfs_rename[_ns]() and unrestricted access
may lead to erroneous values or oops.
Protect ->parent and ->name updates with a irq-safe spinlock
kernfs_rename_lock and implement the following accessors for these
fields.
* kernfs_name() - format the node's name into the specified buffer
* kernfs_path() - format the node's path into the specified buffer
* pr_cont_kernfs_name() - pr_cont a node's name (doesn't need buffer)
* pr_cont_kernfs_path() - pr_cont a node's path (doesn't need buffer)
* kernfs_get_parent() - pin and return a node's parent
All can be called under any context. The recursive sysfs_pathname()
in fs/sysfs/dir.c is replaced with kernfs_path() and
sysfs_rename_dir_ns() is updated to use kernfs_get_parent() instead of
dereferencing parent directly.
v2: Dummy definition of kernfs_path() for !CONFIG_KERNFS was missing
static inline making it cause a lot of build warnings. Add it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:15 +0000 (14:09 -0500)]
kernfs: implement kernfs_node_from_dentry(), kernfs_root_from_sb() and kernfs_rename()
Implement helpers to determine node from dentry and root from
super_block. Also add a kernfs_rename_ns() wrapper which assumes NULL
namespace. These generally make sense and will be used by cgroup.
v2: Some dummy implementations for !CONFIG_SYSFS was missing. Fixed.
Reported by kbuild test robot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:14 +0000 (14:09 -0500)]
kernfs: add kernfs_open_file->priv
Add a private data field to be used by kernfs file operations. This
generally makes sense and will be used by cgroup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:13 +0000 (14:09 -0500)]
kernfs: implement kernfs_ops->atomic_write_len
A write to a kernfs_node is buffered through a kernel buffer. Writes
<= PAGE_SIZE are performed atomically, while larger ones are executed
in PAGE_SIZE chunks. While this is enough for sysfs, cgroup which is
scheduled to be converted to use kernfs needs a bit more control over
it.
This patch adds kernfs_ops->atomic_write_len. If not set (zero), the
behavior stays the same. If set, writes upto the size are executed
atomically and larger writes are rejected with -E2BIG.
A different implementation strategy would be allowing configuring
chunking size while making the original write size available to the
write method; however, such strategy, while being more complicated,
doesn't really buy anything. If the write implementation has to
handle chunking, the specific chunk size shouldn't matter all that
much.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:12 +0000 (14:09 -0500)]
kernfs: allow nodes to be created in the deactivated state
Currently, kernfs_nodes are made visible to userland on creation,
which makes it difficult for kernfs users to atomically succeed or
fail creation of multiple nodes. In addition, if something fails
after creating some nodes, the created nodes might already be in use
and their active refs need to be drained for removal, which has the
potential to introduce tricky reverse locking dependency on active_ref
depending on how the error path is synchronized.
This patch introduces per-root flag KERNFS_ROOT_CREATE_DEACTIVATED.
If set, all nodes under the root are created in the deactivated state
and stay invisible to userland until explicitly enabled by the new
kernfs_activate() API. Also, nodes which have never been activated
are guaranteed to bypass draining on removal thus allowing error paths
to not worry about lockding dependency on active_ref draining.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:11 +0000 (14:09 -0500)]
kernfs: add missing kernfs_active() checks in directory operations
kernfs_iop_lookup(), kernfs_dir_pos() and kernfs_dir_next_pos() were
missing kernfs_active() tests before using the found kernfs_node. As
deactivated state is currently visible only while a node is being
removed, this doesn't pose an actual problem. e.g. lookup succeeding
on a deactivated node doesn't harm anything as the eventual file
operations are gonna fail and those failures are indistinguishible
from the cases in which the lookups had happened before the node was
deactivated.
However, we're gonna allow new nodes to be created deactivated and
then activated explicitly by the kernfs user when it sees fit. This
is to support atomically making multiple nodes visible to userland and
thus those nodes must not be visible to userland before activated.
Let's plug the lookup and readdir holes so that deactivated nodes are
invisible to userland.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:10 +0000 (14:09 -0500)]
kernfs: implement kernfs_syscall_ops->remount_fs() and ->show_options()
Add two super_block related syscall callbacks ->remount_fs() and
->show_options() to kernfs_syscall_ops. These simply forward the
matching super_operations.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:09 +0000 (14:09 -0500)]
kernfs: rename kernfs_dir_ops to kernfs_syscall_ops
We're gonna need non-dir syscall callbacks, which will make dir_ops a
misnomer. Let's rename kernfs_dir_ops to kernfs_syscall_ops.
This is pure rename.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:09:08 +0000 (14:09 -0500)]
kernfs: invoke dir_ops while holding active ref of the target node
kernfs_dir_ops are currently being invoked without any active
reference, which makes it tricky for the invoked operations to
determine whether the objects associated those nodes are safe to
access and will remain that way for the duration of such operations.
kernfs already has active_ref mechanism to deal with this which makes
the removal of a given node the synchronization point for gating the
file operations. There's no reason for dir_ops to be any different.
Update the dir_ops handling so that active_ref is held while the
dir_ops are executing. This guarantees that while a dir_ops is
executing the target nodes stay alive.
As kernfs_dir_ops doesn't have any in-kernel user at this point, this
doesn't affect anybody.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:03:05 +0000 (14:03 -0500)]
sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()
All device_schedule_callback_owner() users are converted to use
device_remove_file_self(). Remove now unused
{sysfs|device}_schedule_callback_owner().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:03:04 +0000 (14:03 -0500)]
s390: use device_remove_file_self() instead of device_schedule_callback()
driver-core now supports synchrnous self-deletion of attributes and
the asynchrnous removal mechanism is scheduled for removal. Use it
instead of device_schedule_callback().
* Conversions in arch/s390/pci/pci_sysfs.c and
drivers/s390/block/dcssblk.c are straightforward.
* drivers/s390/cio/ccwgroup.c is a bit more tricky because
ccwgroup_notifier() was (ab)using device_schedule_callback() to
purely obtain a process context to kick off ungroup operation which
may block from a notifier callback.
Rename ccwgroup_ungroup_callback() to ccwgroup_ungroup() and make it
take ccwgroup_device * instead. The new function is now called
directly from ccwgroup_ungroup_store().
ccwgroup_notifier() chain is updated to explicitly bounce through
ccwgroup_device->ungroup_work. This also removes possible failure
from memory pressure.
Only compile-tested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:03:03 +0000 (14:03 -0500)]
scsi: use device_remove_file_self() instead of device_schedule_callback()
driver-core now supports synchrnous self-deletion of attributes and
the asynchrnous removal mechanism is scheduled for removal. Use it
instead of device_schedule_callback(). This makes "delete" behave
synchronously.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:03:02 +0000 (14:03 -0500)]
pci: use device_remove_file_self() instead of device_schedule_callback()
driver-core now supports synchrnous self-deletion of attributes and
the asynchrnous removal mechanism is scheduled for removal. Use it
instead of device_schedule_callback(). This makes "remove" behave
synchronously.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:03:01 +0000 (14:03 -0500)]
kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers
Sometimes it's necessary to implement a node which wants to delete
nodes including itself. This isn't straightforward because of kernfs
active reference. While a file operation is in progress, an active
reference is held and kernfs_remove() waits for all such references to
drain before completing. For a self-deleting node, this is a deadlock
as kernfs_remove() ends up waiting for an active reference that itself
is sitting on top of.
This currently is worked around in the sysfs layer using
sysfs_schedule_callback() which makes such removals asynchronous.
While it works, it's rather cumbersome and inherently breaks
synchronicity of the operation - the file operation which triggered
the operation may complete before the removal is finished (or even
started) and the removal may fail asynchronously. If a removal
operation is immmediately followed by another operation which expects
the specific name to be available (e.g. removal followed by rename
onto the same name), there's no way to make the latter operation
reliable.
The thing is there's no inherent reason for this to be asynchrnous.
All that's necessary to do this synchronous is a dedicated operation
which drops its own active ref and deactivates self. This patch
implements kernfs_remove_self() and its wrappers in sysfs and driver
core. kernfs_remove_self() is to be called from one of the file
operations, drops the active ref the task is holding, removes the self
node, and restores active ref to the dead node so that the ref is
balanced afterwards. __kernfs_remove() is updated so that it takes an
early exit if the target node is already fully removed so that the
active ref restored by kernfs_remove_self() after removal doesn't
confuse the deactivation path.
This makes implementing self-deleting nodes very easy. The normal
removal path doesn't even need to be changed to use
kernfs_remove_self() for the self-deleting node. The method can
invoke kernfs_remove_self() on itself before proceeding the normal
removal path. kernfs_remove() invoked on the node by the normal
deletion path will simply be ignored.
This will replace sysfs_schedule_callback(). A subtle feature of
sysfs_schedule_callback() is that it collapses multiple invocations -
even if multiple removals are triggered, the removal callback is run
only once. An equivalent effect can be achieved by testing the return
value of kernfs_remove_self() - only the one which gets %true return
value should proceed with actual deletion. All other instances of
kernfs_remove_self() will wait till the enclosing kernfs operation
which invoked the winning instance of kernfs_remove_self() finishes
and then return %false. This trivially makes all users of
kernfs_remove_self() automatically show correct synchronous behavior
even when there are multiple concurrent operations - all "echo 1 >
delete" instances will finish only after the whole operation is
completed by one of the instances.
Note that manipulation of active ref is implemented in separate public
functions - kernfs_[un]break_active_protection().
kernfs_remove_self() is the only user at the moment but this will be
used to cater to more complex cases.
v2: For !CONFIG_SYSFS, dummy version kernfs_remove_self() was missing
and sysfs_remove_file_self() had incorrect return type. Fix it.
Reported by kbuild test bot.
v3: kernfs_[un]break_active_protection() separated out from
kernfs_remove_self() and exposed as public API.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:03:00 +0000 (14:03 -0500)]
kernfs: remove KERNFS_REMOVED
KERNFS_REMOVED is used to mark half-initialized and dying nodes so
that they don't show up in lookups and deny adding new nodes under or
renaming it; however, its role overlaps that of deactivation.
It's necessary to deny addition of new children while removal is in
progress; however, this role considerably intersects with deactivation
- KERNFS_REMOVED prevents new children while deactivation prevents new
file operations. There's no reason to have them separate making
things more complex than necessary.
This patch removes KERNFS_REMOVED.
* Instead of KERNFS_REMOVED, each node now starts its life
deactivated. This means that we now use both atomic_add() and
atomic_sub() on KN_DEACTIVATED_BIAS, which is INT_MIN. The compiler
generates an overflow warnings when negating INT_MIN as the negation
can't be represented as a positive number. Nothing is actually
broken but let's bump BIAS by one to avoid the warnings for archs
which negates the subtrahend..
* A new helper kernfs_active() which tests whether kn->active >= 0 is
added for convenience and lockdep annotation. All KERNFS_REMOVED
tests are replaced with negated kernfs_active() tests.
* __kernfs_remove() is updated to deactivate, but not drain, all nodes
in the subtree instead of setting KERNFS_REMOVED. This removes
deactivation from kernfs_deactivate(), which is now renamed to
kernfs_drain().
* Sanity check on KERNFS_REMOVED in kernfs_put() is replaced with
checks on the active ref.
* Some comment style updates in the affected area.
v2: Reordered before removal path restructuring. kernfs_active()
dropped and kernfs_get/put_active() used instead. RB_EMPTY_NODE()
used in the lookup paths.
v3: Reverted most of v2 except for creating a new node with
KN_DEACTIVATED_BIAS.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:02:59 +0000 (14:02 -0500)]
kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()
There currently are two mechanisms gating active ref lockdep
annotations - KERNFS_LOCKDEP flag and KERNFS_ACTIVE_REF type mask.
The former disables lockdep annotations in kernfs_get/put_active()
while the latter disables all of kernfs_deactivate().
While KERNFS_ACTIVE_REF also behaves as an optimization to skip the
deactivation step for non-file nodes, the benefit is marginal and it
needlessly diverges code paths. Let's drop KERNFS_ACTIVE_REF.
While at it, add a test helper kernfs_lockdep() to test KERNFS_LOCKDEP
flag so that it's more convenient and the related code can be compiled
out when not enabled.
v2: Refreshed on top of ("kernfs: make kernfs_deactivate() honor
KERNFS_LOCKDEP flag"). As the earlier patch already added
KERNFS_LOCKDEP tests to kernfs_deactivate(), those additions are
dropped from this patch and the existing ones are simply converted
to kernfs_lockdep().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:02:58 +0000 (14:02 -0500)]
kernfs: remove kernfs_addrm_cxt
kernfs_addrm_cxt and the accompanying kernfs_addrm_start/finish() were
added because there were operations which should be performed outside
kernfs_mutex after adding and removing kernfs_nodes. The necessary
operations were recorded in kernfs_addrm_cxt and performed by
kernfs_addrm_finish(); however, after the recent changes which
relocated deactivation and unmapping so that they're performed
directly during removal, the only operation kernfs_addrm_finish()
performs is kernfs_put(), which can be moved inside the removal path
too.
This patch moves the kernfs_put() of the base ref to __kernfs_remove()
and remove kernfs_addrm_cxt and kernfs_addrm_start/finish().
* kernfs_add_one() is updated to grab and release kernfs_mutex itself.
sysfs_addrm_start/finish() invocations around it are removed from
all users.
* __kernfs_remove() puts an unlinked node directly instead of chaining
it to kernfs_addrm_cxt. Its callers are updated to grab and release
kernfs_mutex instead of calling kernfs_addrm_start/finish() around
it.
v2: Rebased on top of "kernfs: associate a new kernfs_node with its
parent on creation" which dropped @parent from kernfs_add_one().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:02:57 +0000 (14:02 -0500)]
kernfs: invoke kernfs_unmap_bin_file() directly from kernfs_deactivate()
kernfs_unmap_bin_file() is supposed to unmap all memory mappings of
the target file before kernfs_remove() finishes; however, it currently
is being called from kernfs_addrm_finish() and has the same race
problem as the original implementation of deactivation when there are
multiple removers - only the remover which snatches the node to its
addrm_cxt->removed list is guaranteed to wait for its completion
before returning.
It can be easily fixed by moving kernfs_unmap_bin_file() invocation
from kernfs_addrm_finish() to kernfs_deactivated(). The function may
be called multiple times but that shouldn't do any harm.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:02:56 +0000 (14:02 -0500)]
kernfs: restructure removal path to fix possible premature return
The recursive nature of kernfs_remove() means that, even if
kernfs_remove() is not allowed to be called multiple times on the same
node, there may be race conditions between removal of parent and its
descendants. While we can claim that kernfs_remove() shouldn't be
called on one of the descendants while the removal of an ancestor is
in progress, such rule is unnecessarily restrictive and very difficult
to enforce. It's better to simply allow invoking kernfs_remove() as
the caller sees fit as long as the caller ensures that the node is
accessible.
The current behavior in such situations is broken. Whoever enters
removal path first takes the node off the hierarchy and then
deactivates. Following removers either return as soon as it notices
that it's not the first one or can't even find the target node as it
has already been removed from the hierarchy. In both cases, the
following removers may finish prematurely while the nodes which should
be removed and drained are still being processed by the first one.
This patch restructures so that multiple removers, whether through
recursion or direction invocation, always follow the following rules.
* When there are multiple concurrent removers, only one puts the base
ref.
* Regardless of which one puts the base ref, all removers are blocked
until the target node is fully deactivated and removed.
To achieve the above, removal path now first marks all descendants
including self REMOVED and then deactivates and unlinks leftmost
descendant one-by-one. kernfs_deactivate() is called directly from
__kernfs_removal() and drops and regrabs kernfs_mutex for each
descendant to drain active refs. As this means that multiple removers
can enter kernfs_deactivate() for the same node, the function is
updated so that it can handle multiple deactivators of the same node -
only one actually deactivates but all wait till drain completion.
The restructured removal path guarantees that a removed node gets
unlinked only after the node is deactivated and drained. Combined
with proper multiple deactivator handling, this guarantees that any
invocation of kernfs_remove() returns only after the node itself and
all its descendants are deactivated, drained and removed.
v2: Draining separated into a separate loop (used to be in the same
loop as unlink) and done from __kernfs_deactivate(). This is to
allow exposing deactivation as a separate interface later.
Root node removal was broken in v1 patch. Fixed.
v3: Revert most of v2 except for root node removal fix and
simplification of KERNFS_REMOVED setting loop.
v4: Refreshed on top of ("kernfs: make kernfs_deactivate() honor
KERNFS_LOCKDEP flag").
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:02:55 +0000 (14:02 -0500)]
kernfs: replace kernfs_node->u.completion with kernfs_root->deactivate_waitq
kernfs_node->u.completion is used to notify deactivation completion
from kernfs_put_active() to kernfs_deactivate(). We now allow
multiple racing removals of the same node and the current removal
scheme is no longer correct - kernfs_remove() invocation may return
before the node is properly deactivated if it races against another
removal. The removal path will be restructured to address the issue.
To help such restructure which requires supporting multiple waiters,
this patch replaces kernfs_node->u.completion with
kernfs_root->deactivate_waitq. This makes deactivation event
notifications share a per-root waitqueue_head; however, the wait path
is quite cold and this will also allow shaving one pointer off
kernfs_node.
v2: Refreshed on top of ("kernfs: make kernfs_deactivate() honor
KERNFS_LOCKDEP flag").
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tejun Heo [Mon, 3 Feb 2014 19:02:54 +0000 (14:02 -0500)]
kernfs: make kernfs_deactivate() honor KERNFS_LOCKDEP flag
kernfs_deactivate() forgot to check whether KERNFS_LOCKDEP is set
before performing lockdep annotations and ends up feeding
uninitialized lockdep_map to lockdep triggering warning like the
following on USB stick hotunplug.
usb 1-2: USB disconnect, device number 2
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 62 Comm: khubd Not tainted 3.13.0-work+ #82
Hardware name: empty empty/S3992, BIOS 080011 10/26/2007
ffff880065ca7f60 ffff88013a4ffa08 ffffffff81cfb6bd 0000000000000002
ffff88013a4ffac8 ffffffff810f8530 ffff88013a4fc710 0000000000000002
ffff880100000000 ffffffff82a3db50 0000000000000001 ffff88013a4fc710
Call Trace:
[<
ffffffff81cfb6bd>] dump_stack+0x4e/0x7a
[<
ffffffff810f8530>] __lock_acquire+0x1910/0x1e70
[<
ffffffff810f931a>] lock_acquire+0x9a/0x1d0
[<
ffffffff8127c75e>] kernfs_deactivate+0xee/0x130
[<
ffffffff8127d4c8>] kernfs_addrm_finish+0x38/0x60
[<
ffffffff8127d701>] kernfs_remove_by_name_ns+0x51/0xa0
[<
ffffffff8127b4f1>] remove_files.isra.1+0x41/0x80
[<
ffffffff8127b7e7>] sysfs_remove_group+0x47/0xa0
[<
ffffffff8127b873>] sysfs_remove_groups+0x33/0x50
[<
ffffffff8177d66d>] device_remove_attrs+0x4d/0x80
[<
ffffffff8177e25e>] device_del+0x12e/0x1d0
[<
ffffffff819722c2>] usb_disconnect+0x122/0x1a0
[<
ffffffff819749b5>] hub_thread+0x3c5/0x1290
[<
ffffffff810c6a6d>] kthread+0xed/0x110
[<
ffffffff81d0a56c>] ret_from_fork+0x7c/0xb0
Fix it by making kernfs_deactivate() perform lockdep annotations only
if KERNFS_LOCKDEP is set.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fabio Estevam <festevam@gmail.com>
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Colin Cross [Sat, 21 Dec 2013 00:43:50 +0000 (16:43 -0800)]
dma-buf: avoid using IS_ERR_OR_NULL
dma_buf_map_attachment and dma_buf_vmap can return NULL or
ERR_PTR on a error. This encourages a common buggy pattern in
callers:
sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
if (IS_ERR_OR_NULL(sgt))
return PTR_ERR(sgt);
This causes the caller to return 0 on an error. IS_ERR_OR_NULL
is almost always a sign of poorly-defined error handling.
This patch converts dma_buf_map_attachment to always return
ERR_PTR, and fixes the callers that incorrectly handled NULL.
There are a few more callers that were not checking for NULL
at all, which would have dereferenced a NULL pointer later.
There are also a few more callers that correctly handled NULL
and ERR_PTR differently, I left those alone but they could also
be modified to delete the NULL check.
This patch also converts dma_buf_vmap to always return NULL.
All the callers to dma_buf_vmap only check for NULL, and would
have dereferenced an ERR_PTR and panic'd if one was ever
returned. This is not consistent with the rest of the dma buf
APIs, but matches the expectations of all of the callers.
Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Hugh Dickins [Thu, 6 Feb 2014 23:56:01 +0000 (15:56 -0800)]
cgroup: use an ordered workqueue for cgroup destruction
Sometimes the cleanup after memcg hierarchy testing gets stuck in
mem_cgroup_reparent_charges(), unable to bring non-kmem usage down to 0.
There may turn out to be several causes, but a major cause is this: the
workitem to offline parent can get run before workitem to offline child;
parent's mem_cgroup_reparent_charges() circles around waiting for the
child's pages to be reparented to its lrus, but it's holding cgroup_mutex
which prevents the child from reaching its mem_cgroup_reparent_charges().
Just use an ordered workqueue for cgroup_destroy_wq.
tj: Committing as the temporary fix until the reverse dependency can
be removed from memcg. Comment updated accordingly.
Fixes:
e5fca243abae ("cgroup: use a dedicated workqueue for cgroup destruction")
Suggested-by: Filipe Brandenburger <filbranden@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Tejun Heo <tj@kernel.org>
Tejun Heo [Mon, 3 Feb 2014 19:31:07 +0000 (14:31 -0500)]
nfs: include xattr.h from fs/nfs/nfs3proc.c
fs/nfs/nfs3proc.c is making use of xattr but was getting linux/xattr.h
indirectly through linux/cgroup.h, which will soon drop the inclusion
of xattr.h. Explicitly include linux/xattr.h from nfs3proc.c so that
compilation doesn't fail when linux/cgroup.h drops linux/xattr.h.
As the following cgroup changes will depend on these changes, it
probably would be easier to route this through cgroup branch. Would
that be okay?
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: linux-nfs@vger.kernel.org
Li Zefan [Tue, 28 Jan 2014 03:29:09 +0000 (11:29 +0800)]
cpuset: update MAINTAINERS entry
Add mailing list and tree tag to the entry.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Tejun Heo [Tue, 28 Jan 2014 23:10:37 +0000 (18:10 -0500)]
arm, pm, vmpressure: add missing slab.h includes
arch/arm/mach-tegra/pm.c, kernel/power/console.c and mm/vmpressure.c
were somehow getting slab.h indirectly through cgroup.h which in turn
was getting it indirectly through xattr.h. A scheduled cgroup change
drops xattr.h inclusion from cgroup.h and breaks compilation of these
three files. Add explicit slab.h includes to the three files.
A pending cgroup patch depends on this change and it'd be great if
this can be routed through cgroup/for-3.14-fixes branch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-tegra@vger.kernel.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: cgroups@vger.kernel.org
Linus Torvalds [Mon, 3 Feb 2014 00:42:13 +0000 (16:42 -0800)]
Linus 3.14-rc1
Linus Torvalds [Mon, 3 Feb 2014 00:32:53 +0000 (16:32 -0800)]
Merge branch 'parisc-3.14' of git://git./linux/kernel/git/deller/parisc-linux
Pull parisc updates from Helge Deller:
"The three major changes in this patchset is a implementation for
flexible userspace memory maps, cache-flushing fixes (again), and a
long-discussed ABI change to make EWOULDBLOCK the same value as
EAGAIN.
parisc has been the only platform where we had EWOULDBLOCK != EAGAIN
to keep HP-UX compatibility. Since we will probably never implement
full HP-UX support, we prefer to drop this compatibility to make it
easier for us with Linux userspace programs which mostly never checked
for both values. We don't expect major fall-outs because of this
change, and if we face some, we will simply rebuild the necessary
applications in the debian archives"
* 'parisc-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: add flexible mmap memory layout support
parisc: Make EWOULDBLOCK be equal to EAGAIN on parisc
parisc: convert uapi/asm/stat.h to use native types only
parisc: wire up sched_setattr and sched_getattr
parisc: fix cache-flushing
parisc/sti_console: prefer Linux fonts over built-in ROM fonts
Mikulas Patocka [Tue, 28 Jan 2014 23:11:33 +0000 (00:11 +0100)]
hpfs: optimize quad buffer loading
HPFS needs to load 4 consecutive 512-byte sectors when accessing the
directory nodes or bitmaps. We can't switch to 2048-byte block size
because files are allocated in the units of 512-byte sectors.
Previously, the driver would allocate a 2048-byte area using kmalloc,
copy the data from four buffers to this area and eventually copy them
back if they were modified.
In the current implementation of the buffer cache, buffers are allocated
in the pagecache. That means that 4 consecutive 512-byte buffers are
stored in consecutive areas in the kernel address space. So, we don't
need to allocate extra memory and copy the content of the buffers there.
This patch optimizes the code to avoid copying the buffers. It checks
if the four buffers are stored in contiguous memory - if they are not,
it falls back to allocating a 2048-byte area and copying data there.
Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mikulas Patocka [Tue, 28 Jan 2014 23:10:44 +0000 (00:10 +0100)]
hpfs: remember free space
Previously, hpfs scanned all bitmaps each time the user asked for free
space using statfs. This patch changes it so that hpfs scans the
bitmaps only once, remembes the free space and on next invocation of
statfs it returns the value instantly.
New versions of wine are hammering on the statfs syscall very heavily,
making some games unplayable when they're stored on hpfs, with load
times in minutes.
This should be backported to the stable kernels because it fixes
user-visible problem (excessive level load times in wine).
Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Helge Deller [Fri, 31 Jan 2014 21:19:52 +0000 (22:19 +0100)]
parisc: add flexible mmap memory layout support
Add support for the flexible mmap memory layout (as described in
http://lwn.net/Articles/91829). This is especially very interesting on
parisc since we currently only support 32bit userspace (even with a
64bit Linux kernel).
Signed-off-by: Helge Deller <deller@gmx.de>
Guy Martin [Thu, 16 Jan 2014 16:17:53 +0000 (17:17 +0100)]
parisc: Make EWOULDBLOCK be equal to EAGAIN on parisc
On Linux, only parisc uses a different value for EWOULDBLOCK which
causes a lot of troubles for applications not checking for both values.
Since the hpux compat is long dead, make EWOULDBLOCK behave the same as
all other architectures.
Signed-off-by: Guy Martin <gmsoft@tuxicoman.be>
Signed-off-by: Helge Deller <deller@gmx.de>
Helge Deller [Fri, 31 Jan 2014 22:00:38 +0000 (23:00 +0100)]
parisc: convert uapi/asm/stat.h to use native types only
The stat.h header file is exported to userspace. Some userspace
applications failed to compile due to missing/unknown types, so we
better convert it to use native types only (like it's done on other
architectures too).
Signed-off-by: Helge Deller <deller@gmx.de>
Helge Deller [Fri, 31 Jan 2014 21:29:17 +0000 (22:29 +0100)]
parisc: wire up sched_setattr and sched_getattr
Signed-off-by: Helge Deller <deller@gmx.de>
Helge Deller [Fri, 31 Jan 2014 20:33:17 +0000 (21:33 +0100)]
parisc: fix cache-flushing
This commit:
f8dae00684d678afa13041ef170cecfd1297ed40: parisc: Ensure full cache coherency for kmap/kunmap
caused negative caching side-effects, e.g. hanging processes with expect and
too many inequivalent alias messages from flush_dcache_page() on Debian 5 systems.
This patch now partly reverts it and has been in production use on our debian buildd
makeservers since a week without any major problems.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Helge Deller <deller@gmx.de>
Helge Deller [Fri, 31 Jan 2014 14:39:40 +0000 (15:39 +0100)]
parisc/sti_console: prefer Linux fonts over built-in ROM fonts
The built-in ROM fonts lack many necessary ASCII characters, which is
why it makes sens to prefer the Linux fonts instead if they are
available. This makes consoles on STI graphics cards which are not
supported by the stifb driver (e.g. Visualize FXe) looks much nicer.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v3.13
Linus Torvalds [Sun, 2 Feb 2014 19:30:57 +0000 (11:30 -0800)]
Merge branch 'hwmon-for-linus' of git://git./linux/kernel/git/jdelvare/staging
Pull hwmon kconfig fixes from Jean Delvare.
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
hwmon: Fix SENSORS_TMP102 dependencies to eliminate build errors
hwmon: Fix SENSORS_LM75 dependencies to eliminate build errors
Linus Torvalds [Sun, 2 Feb 2014 19:30:08 +0000 (11:30 -0800)]
Merge branch 'slab/next' of git://git./linux/kernel/git/penberg/linux
Pull SLAB changes from Pekka Enberg:
"Random bug fixes that have accumulated in my inbox over the past few
months"
* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
mm: Fix warning on make htmldocs caused by slab.c
mm: slub: work around unneeded lockdep warning
mm: sl[uo]b: fix misleading comments
slub: Fix possible format string bug.
slub: use lockdep_assert_held
slub: Fix calculation of cpu slabs
slab.h: remove duplicate kmalloc declaration and fix kernel-doc warnings
Linus Torvalds [Sun, 2 Feb 2014 19:28:48 +0000 (11:28 -0800)]
Merge branch 'release' of git://git./linux/kernel/git/lenb/linux
Pull turbostat updates from Len Brown.
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
tools/power turbostat: introduce -s to dump counters
tools/power turbostat: remove unused command line option
turbostat: Add option to report joules consumed per sample
turbostat: run on HSX
turbostat: Add a .gitignore to ignore the compiled turbostat binary
turbostat: Clean up error handling; disambiguate error messages; use err and errx
turbostat: Factor out common function to open file and exit on failure
turbostat: Add a helper to parse a single int out of a file
turbostat: Check return value of fscanf
turbostat: Use GCC's CPUID functions to support PIC
turbostat: Don't attempt to printf an off_t with %zx
turbostat: Don't put unprocessed uapi headers in the include path
Linus Torvalds [Sun, 2 Feb 2014 19:11:06 +0000 (11:11 -0800)]
Merge tag 'fixes-for-linus' of git://git./linux/kernel/git/arm/arm-soc
Pull ARM SoC fixes from Olof Johansson:
"Here's a set of patches for (hopefully) -rc1. Some of them are fixes,
but a good number of them also do things such as enable new drivers in
the defconfigs for platforms that have such devices, increases
coverage of the multiplatform defconfig and some DTS changes that
plumbs up some of the devices that now have bindings and driver
support.
The commit dates are recent; we've mostly collected these fixes in the
last few days but I also had to rebuild the branch yesterday to sort
out some internal conflicts which reset the timestamps. The changes
should have been tested by each platform maintainer already (and few
of them have cross-platform impact) so I'm personally not too
concerned by it at this time"
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (23 commits)
ARM: multi_v7_defconfig: remove redundant entries and re-enable TI_EDMA
ARM: multi_v7_defconfig: add mvebu drivers
clocksource: kona: Add basic use of external clock
drivers: bus: fix CCI driver kcalloc call parameters swap
ARM: dts: bcm28155-ap: Fix Card Detection GPIO
ARM: multi_v7_defconfig: Select CONFIG_AT803X_PHY
ARM: keystone: config: fix build warning when CONFIG_DMADEVICES is not set
MAINTAINERS: ARM: SiRF: use regex patterns to involve all SiRF drivers
ARM: dts: zynq: Add SDHCI nodes
ARM: hisi: don't select SMP
ARM: tegra: rebuild tegra_defconfig to add DEBUG_FS
ARM: multi_v7: copy most options from tegra_defconfig
ARM: iop32x: fix power off handling for the EM7210 board
ARM: integrator: restore static map on the CP
ARM: msm_defconfig: Enable MSM clock drivers
ARM: dts: msm: Add clock controller nodes and hook into uart
ARM: OMAP4+: move errata initialization to omap4_pm_init_early
ARM: OMAP4460: cpuidle: Extend PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD on cpuidle
ARM: mvebu: fix compilation warning on Armada 370 (i.e. non-SMP)
ARM: shmobile: r8a7790.dtsi: ficx i2c[0-3] clock reference
...
Jean Delvare [Sun, 2 Feb 2014 16:59:07 +0000 (17:59 +0100)]
hwmon: Fix SENSORS_TMP102 dependencies to eliminate build errors
Similar to what was done for the lm75 driver.
Add depends on THERMAL since that is what provides the
register/unregister functions above, but only if THERMAL_OF was
selected as this is an optional feature of the driver.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Eduardo Valentin <eduardo.valentin@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Jean Delvare [Sun, 2 Feb 2014 16:59:07 +0000 (17:59 +0100)]
hwmon: Fix SENSORS_LM75 dependencies to eliminate build errors
Based on an earlier attempt by Randy Dunlap.
Fix SENSORS_LM75 dependencies to eliminate build errors:
drivers/built-in.o: In function `lm75_remove':
lm75.c:(.text+0x12bd8c): undefined reference to `thermal_zone_of_sensor_unregister'
drivers/built-in.o: In function `lm75_probe':
lm75.c:(.text+0x12c123): undefined reference to `thermal_zone_of_sensor_register'
Add depends on THERMAL since that is what provides the
register/unregister functions above, but only if THERMAL_OF was
selected as this is an optional feature of the driver.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Eduardo Valentin <eduardo.valentin@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Andy Shevchenko [Thu, 23 Jan 2014 15:13:15 +0000 (17:13 +0200)]
tools/power turbostat: introduce -s to dump counters
The new option allows just run turbostat and get dump of counter values. It's
useful when we have something more than one program to test.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Andy Shevchenko [Thu, 23 Jan 2014 15:13:14 +0000 (17:13 +0200)]
tools/power turbostat: remove unused command line option
The -s is not used, let's remove it, and update quick help accordingly.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Linus Torvalds [Sat, 1 Feb 2014 19:03:16 +0000 (11:03 -0800)]
Merge branch 'misc' of git://git./linux/kernel/git/mmarek/kbuild
Pull misc kbuild changes from Michal Marek:
"The non-critical part of kbuild is small this time:
- Three fixes for make deb-pkg
- A new coccinelle check
One of the deb-pkg fixes is a leftover from the last merge window,
hence the merge commit"
* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
deb-pkg: Fix building for MIPS big-endian or ARM OABI
deb-pkg: Fix cross-building linux-headers package
scripts: Coccinelle script for pm_runtime_* return checks with IS_ERR_VALUE
deb-pkg: Inhibit initramfs builders if CONFIG_BLK_DEV_INITRD is not set
Pali Rohár [Tue, 28 Jan 2014 20:26:44 +0000 (20:26 +0000)]
afs: proc cells and rootcell are writeable
Both proc files are writeable and used for configuring cells. But
there is missing correct mode flag for writeable files. Without
this patch both proc files are read only.
[ It turns out they aren't really read-only, since root can write to
them even if the write bit isn't set due to CAP_DAC_OVERRIDE ]
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Heiko Carstens [Fri, 31 Jan 2014 06:50:36 +0000 (07:50 +0100)]
tile: remove compat_sys_lookup_dcookie declaration to fix compile error
With commit
d8d14bd09cdd ("fs/compat: fix lookup_dcookie() parameter
handling") I changed the type of the len parameter of the
lookup_dcookie() syscall.
However I missed that there was still a stale declaration in
arch/tile/.. which now causes a compile error on tile:
In file included from fs/dcookies.c:28:0:
include/linux/compat.h:425:17: error: conflicting types for 'compat_sys_lookup_dcookie'
fs/dcookies.c:207:1: error: conflicting types for 'compat_sys_lookup_dcookie'
Simply remove the declaration in the tile architecture, which is only a
leftover from before the different compat lookup_dcookie() versions have
been merged. The correct declaration is now in include/linux/compat.h
The build error was reported by Fenguang's build bot.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Sat, 1 Feb 2014 18:52:45 +0000 (10:52 -0800)]
Merge branch 'for-linus' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs fixes from Steve French:
"A set of cifs fixes (mostly for symlinks, and SMB2 xattrs) and
cleanups"
* 'for-linus' of git://git.samba.org/sfrench/cifs-2.6:
cifs: Fix check for regular file in couldbe_mf_symlink()
[CIFS] Fix SMB2 mounts so they don't try to set or get xattrs via cifs
CIFS: Cleanup cifs open codepath
CIFS: Remove extra indentation in cifs_sfu_type
CIFS: Cleanup cifs_mknod
CIFS: Cleanup CIFSSMBOpen
cifs: Add support for follow_link on dfs shares under posix extensions
cifs: move unix extension call to cifs_query_symlink()
cifs: Re-order M-F Symlink code
cifs: Add create MFSymlinks to protocol ops struct
cifs: use protocol specific call for query_mf_symlink()
cifs: Rename MF symlink function names
cifs: Rename and cleanup open_query_close_cifs_symlink()
cifs: Fix memory leak in cifs_hardlink()
Linus Torvalds [Sat, 1 Feb 2014 18:43:45 +0000 (10:43 -0800)]
Merge branch 'for-linus' of git://git./linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
"Several obvious fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
Fix mountpoint reference leakage in linkat
hfsplus: use xattr handlers for removexattr
Typo in compat_sys_lseek() declaration
fs/super.c: sync ro remount after blocking writers
vfs: unexport the getname() symbol
Linus Torvalds [Sat, 1 Feb 2014 18:29:59 +0000 (10:29 -0800)]
Merge tag 'staging-3.14-rc1' of git://git./linux/kernel/git/gregkh/staging
Pull rtl8812ae staging wireless driver from Greg KH:
"Here's a single staging driver for a wireless chipset that has shown
up in the SteamBox hardware. It is merged separately from the "main"
staging pull request to sync up with the wireless api changes that
came in from the networking tree.
It's self-contained and works for me and others. Larry will be
replacing it with a "real" driver for 3.15, but for now this one is
needed"
* tag 'staging-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: r8821ae: Enable build by reverting BROKEN marking
staging: r8821ae: Fix build problems
Staging: rtl8812ae: disable due to build errors
Staging: rtl8821ae: add TODO file
Staging: rtl8821ae: removed unused functions and variables
Staging: rtl8821ae: rc.c: fix up function prototypes
Staging: rtl8812ae: Add Realtek 8821 PCI WIFI driver
Rafael J. Wysocki [Sat, 1 Feb 2014 14:38:29 +0000 (15:38 +0100)]
Revert "PCI: Remove from bus_list and release resources in pci_release_dev()"
Revert commit
ef83b0781a73 "PCI: Remove from bus_list and release
resources in pci_release_dev()" that made some nasty race conditions
become possible. For example, if a Thunderbolt link is unplugged
and then replugged immediately, the pci_release_dev() resulting from
the hot-remove code path may be racing with the hot-add code path
which after that commit causes various kinds of breakage to happen
(up to and including a hard crash of the whole system).
Moreover, the problem that commit
ef83b0781a73 attempted to address
cannot happen any more after commit
8a4c5c329de7 "PCI: Check parent
kobject in pci_destroy_dev()", because pci_destroy_dev() will now
return immediately if it has already been executed for the given
device.
Note, however, that the invocation of msi_remove_pci_irq_vectors()
removed by commit
ef83b0781a73 from pci_free_resources() along with
the other changes made by it is not added back because of subsequent
code changes depending on that modification.
Fixes:
ef83b0781a73 (PCI: Remove from bus_list and release resources in pci_release_dev())
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Olof Johansson [Fri, 31 Jan 2014 23:21:08 +0000 (15:21 -0800)]
ARM: multi_v7_defconfig: remove redundant entries and re-enable TI_EDMA
TI_EDMA fell out of automatically selected options in the multi_v7
defconfig due to a select being removed from the davinci Kconfig entry. So
we need to re-enable explicitly to not regress some platforms.
The rest is just the result of running 'make multi_v7_defconfig + make
savedefconfig' to remove entries that are no longer needed due to changed
dependencies/selects or defaults.
Signed-off-by: Olof Johansson <olof@lixom.net>
Olof Johansson [Fri, 31 Jan 2014 23:20:07 +0000 (15:20 -0800)]
ARM: multi_v7_defconfig: add mvebu drivers
Recent boot farm testing has highlighted some issues with mvebu and
multiplatform kernels. Increase the test coverage so we can discover
these issues earlier.
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Olof Johansson <olof@lixom.net>
Tim Kryger [Thu, 5 Dec 2013 19:20:43 +0000 (11:20 -0800)]
clocksource: kona: Add basic use of external clock
When an clock is specified in the device tree, enable it and use it to
determine the external clock frequency.
Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Christian Daudt <bcm@fixthebug.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Christian Daudt <bcm@fixthebug.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
Linus Torvalds [Fri, 31 Jan 2014 23:39:07 +0000 (15:39 -0800)]
Merge tag 'nfs-for-3.14-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client bugfixes from Trond Myklebust:
"Highlights:
- Fix several races in nfs_revalidate_mapping
- NFSv4.1 slot leakage in the pNFS files driver
- Stable fix for a slot leak in nfs40_sequence_done
- Don't reject NFSv4 servers that support ACLs with only ALLOW aces"
* tag 'nfs-for-3.14-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
nfs: initialize the ACL support bits to zero.
NFSv4.1: Cleanup
NFSv4.1: Clean up nfs41_sequence_done
NFSv4: Fix a slot leak in nfs40_sequence_done
NFSv4.1 free slot before resending I/O to MDS
nfs: add memory barriers around NFS_INO_INVALID_DATA and NFS_INO_INVALIDATING
NFS: Fix races in nfs_revalidate_mapping
sunrpc: turn warn_gssd() log message into a dprintk()
NFS: fix the handling of NFS_INO_INVALID_DATA flag in nfs_revalidate_mapping
nfs: handle servers that support only ALLOW ACE type.