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2012-11-19cgroup: rename ->create/post_create/pre_destroy/destroy() to ↵Tejun Heo13-121/+132
->css_alloc/online/offline/free() Rename cgroup_subsys css lifetime related callbacks to better describe what their roles are. Also, update documentation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: allow ->post_create() to failTejun Heo3-12/+23
There could be cases where controllers want to do initialization operations which may fail from ->post_create(). This patch makes ->post_create() return -errno to indicate failure and online_css() relay such failures. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
2012-11-19cgroup: update cgroup_create() failure pathTejun Heo1-7/+14
cgroup_create() was ignoring failure of cgroupfs files. Update it such that, if file creation fails, it rolls back by calling cgroup_destroy_locked() and returns failure. Note that error out goto labels are renamed. The labels are a bit confusing but will become better w/ later cgroup operation renames. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: use mutex_trylock() when grabbing i_mutex of a new cgroup directoryTejun Heo1-3/+9
All cgroup directory i_mutexes nest outside cgroup_mutex; however, new directory creation is a special case. A new cgroup directory is created while holding cgroup_mutex. Populating the new directory requires both the new directory's i_mutex and cgroup_mutex. Because all directory i_mutexes nest outside cgroup_mutex, grabbing both requires releasing cgroup_mutex first, which isn't a good idea as the new cgroup isn't yet ready to be manipulated by other cgroup opreations. This is worked around by grabbing the new directory's i_mutex while holding cgroup_mutex before making it visible. As there's no other user at that point, grabbing the i_mutex under cgroup_mutex can't lead to deadlock. cgroup_create_file() was using I_MUTEX_CHILD to tell lockdep not to worry about the reverse locking order; however, this creates pseudo locking dependency cgroup_mutex -> I_MUTEX_CHILD, which isn't true - all directory i_mutexes are still nested outside cgroup_mutex. This pseudo locking dependency can lead to spurious lockdep warnings. Use mutex_trylock() instead. This will always succeed and lockdep doesn't create any locking dependency for it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: simplify cgroup_load_subsys() failure pathTejun Heo1-11/+10
Now that cgroup_unload_subsys() can tell whether the root css is online or not, we can safely call cgroup_unload_subsys() after idr init failure in cgroup_load_subsys(). Replace the manual unrolling and invoke cgroup_unload_subsys() on failure. This drops cgroup_mutex inbetween but should be safe as the subsystem will fail try_module_get() and thus can't be mounted inbetween. As this means that cgroup_unload_subsys() can be called before css_sets are rehashed, remove BUG_ON() on %NULL css_set->subsys[] from cgroup_unload_subsys(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: introduce CSS_ONLINE flag and on/offline_css() helpersTejun Heo2-23/+43
New helpers on/offline_css() respectively wrap ->post_create() and ->pre_destroy() invocations. online_css() sets CSS_ONLINE after ->post_create() is complete and offline_css() invokes ->pre_destroy() iff CSS_ONLINE is set and clears it while also handling the temporary dropping of cgroup_mutex. This patch doesn't introduce any behavior change at the moment but will be used to improve cgroup_create() failure path and allow ->post_create() to fail. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: separate out cgroup_destroy_locked()Tejun Heo1-15/+25
Separate out cgroup_destroy_locked() from cgroup_destroy(). This will be later used in cgroup_create() failure path. While at it, add lockdep asserts on i_mutex and cgroup_mutex, and move @d and @parent assignments to their declarations. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: fix harmless bugs in cgroup_load_subsys() fail path and ↵Tejun Heo1-1/+14
cgroup_unload_subsys() * If idr init fails, cgroup_load_subsys() cleared dummytop->subsys[] before calilng ->destroy() making CSS inaccessible to the callback, and didn't unlink ss->sibling. As no modular controller uses ->use_id, this doesn't cause any actual problems. * cgroup_unload_subsys() was forgetting to free idr, call ->pre_destroy() and clear ->active. As there currently is no modular controller which uses ->use_id, ->pre_destroy() or ->active, this doesn't cause any actual problems. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: lock cgroup_mutex in cgroup_init_subsys()Tejun Heo1-0/+4
Make cgroup_init_subsys() grab cgroup_mutex while initializing a subsystem so that all helpers and callbacks are called under the context they expect. This isn't strictly necessary as cgroup_init_subsys() doesn't race with anybody but will allow adding lockdep assertions. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: trivial cleanup for cgroup_init/load_subsys()Tejun Heo1-3/+3
Consistently use @css and @dummytop in these two functions instead of referring to them indirectly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: make CSS_* flags bit masks instead of bit positionsTejun Heo2-5/+5
Currently, CSS_* flags are defined as bit positions and manipulated using atomic bitops. There's no reason to use atomic bitops for them and bit positions are clunkier to deal with than bit masks. Make CSS_* bit masks instead and use the usual C bitwise operators to access them. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: cgroup->dentry isn't a RCU pointerTejun Heo2-6/+7
cgroup->dentry is marked and used as a RCU pointer; however, it isn't one - the final dentry put doesn't go through call_rcu(). cgroup and dentry share the same RCU freeing rule via synchronize_rcu() in cgroup_diput() (kfree_rcu() used on cgrp is unnecessary). If cgrp is accessible under RCU read lock, so is its dentry and dereferencing cgrp->dentry doesn't need any further RCU protection or annotation. While not being accurate, before the previous patch, the RCU accessors served a purpose as memory barriers - cgroup->dentry used to be assigned after the cgroup was made visible to cgroup_path(), so the assignment and dereferencing in cgroup_path() needed the memory barrier pair. Now that list_add_tail_rcu() happens after cgroup->dentry is assigned, this no longer is necessary. Remove the now unnecessary and misleading RCU annotations from cgroup->dentry. To make up for the removal of rcu_dereference_check() in cgroup_path(), add an explicit rcu_lockdep_assert(), which asserts the dereference rule of @cgrp, not cgrp->dentry. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: create directory before linking while creating a new cgroupTejun Heo1-18/+12
While creating a new cgroup, cgroup_create() links the newly allocated cgroup into various places before trying to create its directory. Because cgroup life-cycle is tied to the vfs objects, this makes it impossible to use cgroup_rmdir() for rolling back creation - the removal logic depends on having full vfs objects. This patch moves directory creation above linking and collect linking operations to one place. This allows directory creation failure to share error exit path with css allocation failures and any failure sites afterwards (to be added later) can use cgroup_rmdir() logic to undo creation. Note that this also makes the memory barriers around cgroup->dentry, which currently is misleadingly using RCU operations, unnecessary. This will be handled in the next patch. While at it, locking BUG_ON() on i_mutex is converted to lockdep_assert_held(). v2: Patch originally removed %NULL dentry check in cgroup_path(); however, Li pointed out that this patch doesn't make it unnecessary as ->create() may call cgroup_path(). Drop the change for now. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: open-code cgroup_create_dir()Tejun Heo1-25/+5
The operation order of cgroup creation is about to change and cgroup_create_dir() is more of a hindrance than a proper abstraction. Open-code it by moving the parent nlink adjustment next to self nlink adjustment in cgroup_create_file() and the rest to cgroup_create(). This patch doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: initialize cgrp->allcg_node in init_cgroup_housekeeping()Tejun Heo1-0/+1
Not strictly necessary but it's annoying to have uninitialized list_head around. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-19cgroup: remove incorrect dget/dput() pair in cgroup_create_dir()Tejun Heo1-2/+0
cgroup_create_dir() does weird dancing with dentry refcnt. On success, it gets and then puts it achieving nothing. On failure, it puts but there isn't no matching get anywhere leading to the following oops if cgroup_create_file() fails for whatever reason. ------------[ cut here ]------------ kernel BUG at /work/os/work/fs/dcache.c:552! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU 2 Pid: 697, comm: mkdir Not tainted 3.7.0-rc4-work+ #3 Bochs Bochs RIP: 0010:[<ffffffff811d9c0c>] [<ffffffff811d9c0c>] dput+0x1dc/0x1e0 RSP: 0018:ffff88001a3ebef8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88000e5b1ef8 RCX: 0000000000000403 RDX: 0000000000000303 RSI: 2000000000000000 RDI: ffff88000e5b1f58 RBP: ffff88001a3ebf18 R08: ffffffff82c76960 R09: 0000000000000001 R10: ffff880015022080 R11: ffd9bed70f48a041 R12: 00000000ffffffea R13: 0000000000000001 R14: ffff88000e5b1f58 R15: 00007fff57656d60 FS: 00007ff05fcb3800(0000) GS:ffff88001fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004046f0 CR3: 000000001315f000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process mkdir (pid: 697, threadinfo ffff88001a3ea000, task ffff880015022080) Stack: ffff88001a3ebf48 00000000ffffffea 0000000000000001 0000000000000000 ffff88001a3ebf38 ffffffff811cc889 0000000000000001 ffff88000e5b1ef8 ffff88001a3ebf68 ffffffff811d1fc9 ffff8800198d7f18 ffff880019106ef8 Call Trace: [<ffffffff811cc889>] done_path_create+0x19/0x50 [<ffffffff811d1fc9>] sys_mkdirat+0x59/0x80 [<ffffffff811d2009>] sys_mkdir+0x19/0x20 [<ffffffff81be1e02>] system_call_fastpath+0x16/0x1b Code: 00 48 8d 90 18 01 00 00 48 89 93 c0 00 00 00 4c 89 a0 18 01 00 00 48 8b 83 a0 00 00 00 83 80 28 01 00 00 01 e8 e6 6f a0 00 eb 92 <0f> 0b 66 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 fe 41 RIP [<ffffffff811d9c0c>] dput+0x1dc/0x1e0 RSP <ffff88001a3ebef8> ---[ end trace 1277bcfd9561ddb0 ]--- Fix it by dropping the unnecessary dget/dput() pair. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
2012-11-09cgroup_freezer: implement proper hierarchy supportTejun Heo2-59/+165
Up until now, cgroup_freezer didn't implement hierarchy properly. cgroups could be arranged in hierarchy but it didn't make any difference in how each cgroup_freezer behaved. They all operated separately. This patch implements proper hierarchy support. If a cgroup is frozen, all its descendants are frozen. A cgroup is thawed iff it and all its ancestors are THAWED. freezer.self_freezing shows the current freezing state for the cgroup itself. freezer.parent_freezing shows whether the cgroup is freezing because any of its ancestors is freezing. freezer_post_create() locks the parent and new cgroup and inherits the parent's state and freezer_change_state() applies new state top-down using cgroup_for_each_descendant_pre() which guarantees that no child can escape its parent's state. update_if_frozen() uses cgroup_for_each_descendant_post() to propagate frozen states bottom-up. Synchronization could be coarser and easier by using a single mutex to protect all hierarchy operations. Finer grained approach was used because it wasn't too difficult for cgroup_freezer and I think it's beneficial to have an example implementation and cgroup_freezer is rather simple and can serve a good one. As this makes cgroup_freezer properly hierarchical, freezer_subsys.broken_hierarchy marking is removed. Note that this patch changes userland visible behavior - freezing a cgroup now freezes all its descendants too. This behavior change is intended and has been warned via .broken_hierarchy. v2: Michal spotted a bug in freezer_change_state() - descendants were inheriting from the wrong ancestor. Fixed. v3: Documentation/cgroups/freezer-subsystem.txt updated. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz>
2012-11-09cgroup_freezer: add ->post_create() and ->pre_destroy() and track online stateTejun Heo1-2/+40
A cgroup is online and visible to iteration between ->post_create() and ->pre_destroy(). This patch introduces CGROUP_FREEZER_ONLINE and toggles it from the newly added freezer_post_create() and freezer_pre_destroy() while holding freezer->lock such that a cgroup_freezer can be reilably distinguished to be online. This will be used by full hierarchy support. ONLINE test is added to freezer_apply_state() but it currently doesn't make any difference as freezer_write() can only be called for an online cgroup. Adjusting system_freezing_cnt on destruction is moved from freezer_destroy() to the new freezer_pre_destroy() for consistency. This patch doesn't introduce any noticeable behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
2012-11-09cgroup_freezer: introduce CGROUP_FREEZING_[SELF|PARENT]Tejun Heo1-8/+47
Introduce FREEZING_SELF and FREEZING_PARENT and make FREEZING OR of the two flags. This is to prepare for full hierarchy support. freezer_apply_date() is updated such that it can handle setting and clearing of both flags. The two flags are also exposed to userland via read-only files self_freezing and parent_freezing. Other than the added cgroupfs files, this patch doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
2012-11-09cgroup_freezer: make freezer->state mask of flagsTejun Heo1-33/+27
freezer->state was an enum value - one of THAWED, FREEZING and FROZEN. As the scheduled full hierarchy support requires more than one freezing condition, switch it to mask of flags. If FREEZING is not set, it's thawed. FREEZING is set if freezing or frozen. If frozen, both FREEZING and FROZEN are set. Now that tasks can be attached to an already frozen cgroup, this also makes freezing condition checks more natural. This patch doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
2012-11-09cgroup_freezer: prepare freezer_change_state() for full hierarchy supportTejun Heo1-18/+30
* Make freezer_change_state() take bool @freeze instead of enum freezer_state. * Separate out freezer_apply_state() out of freezer_change_state(). This makes freezer_change_state() a rather silly thin wrapper. It will be filled with hierarchy handling later on. This patch doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
2012-11-09cgroup_freezer: trivial cleanupsTejun Heo1-22/+19
* Clean-up indentation and line-breaks. Drop the invalid comment about freezer->lock. * Make all internal functions take @freezer instead of both @cgroup and @freezer. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
2012-11-09cgroup: implement generic child / descendant walk macrosTejun Heo2-0/+180
Currently, cgroup doesn't provide any generic helper for walking a given cgroup's children or descendants. This patch adds the following three macros. * cgroup_for_each_child() - walk immediate children of a cgroup. * cgroup_for_each_descendant_pre() - visit all descendants of a cgroup in pre-order tree traversal. * cgroup_for_each_descendant_post() - visit all descendants of a cgroup in post-order tree traversal. All three only require the user to hold RCU read lock during traversal. Verifying that each iterated cgroup is online is the responsibility of the user. When used with proper synchronization, cgroup_for_each_descendant_pre() can be used to propagate state updates to descendants in reliable way. See comments for details. v2: s/config/state/ in commit message and comments per Michal. More documentation on synchronization rules. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujisu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-09cgroup: use rculist ops for cgroup->childrenTejun Heo2-5/+4
Use RCU safe list operations for cgroup->children. This will be used to implement cgroup children / descendant walking which can be used by controllers. Note that cgroup_create() now puts a new cgroup at the end of the ->children list instead of head. This isn't strictly necessary but is done so that the iteration order is more conventional. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-09cgroup: add cgroup_subsys->post_create()Tejun Heo2-2/+14
Currently, there's no way for a controller to find out whether a new cgroup finished all ->create() allocatinos successfully and is considered "live" by cgroup. This becomes a problem later when we add generic descendants walking to cgroup which can be used by controllers as controllers don't have a synchronization point where it can synchronize against new cgroups appearing in such walks. This patch adds ->post_create(). It's called after all ->create() succeeded and the cgroup is linked into the generic cgroup hierarchy. This plays the counterpart of ->pre_destroy(). When used in combination with the to-be-added generic descendant iterators, ->post_create() can be used to implement reliable state inheritance. It will be explained with the descendant iterators. v2: Added a paragraph about its future use w/ descendant iterators per Michal. v3: Forgot to add ->post_create() invocation to cgroup_load_subsys(). Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
2012-11-08cgroup: set 'start' with the right value in cgroup_path.Tao Ma1-2/+2
'start' is set to buf + buflen and do the '--' immediately. Just set it to 'buf + buflen - 1' directly. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com>
2012-11-07device_cgroup: add lockdep assertsTejun Heo1-0/+12
device_cgroup uses RCU safe ->exceptions list which is write-protected by devcgroup_mutex and has had some issues using locking correctly. Add lockdep asserts to utility functions so that future errors can be easily detected. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Cc: Aristeu Rozanski <aris@redhat.com> Cc: Li Zefan <lizefan@huawei.com>
2012-11-07Merge branch 'cgroup/for-3.7-fixes' into cgroup/for-3.8Tejun Heo1187-12717/+16301
This is to receive device_cgroup fixes so that further device_cgroup changes can be made in cgroup/for-3.8. Signed-off-by: Tejun Heo <tj@kernel.org>
2012-11-07device_cgroup: fix RCU usageTejun Heo1-3/+3
dev_cgroup->exceptions is protected with devcgroup_mutex for writes and RCU for reads; however, RCU usage isn't correct. * dev_exception_clean() doesn't use RCU variant of list_del() and kfree(). The function can race with may_access() and may_access() may end up dereferencing already freed memory. Use list_del_rcu() and kfree_rcu() instead. * may_access() may be called only with RCU read locked but doesn't use RCU safe traversal over ->exceptions. Use list_for_each_entry_rcu(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Cc: stable@vger.kernel.org Cc: Aristeu Rozanski <aris@redhat.com> Cc: Li Zefan <lizefan@huawei.com>
2012-11-06device_cgroup: fix unchecked cgroup parent usageAristeu Rozanski1-2/+10
In 4cef7299b478687 ("device_cgroup: add proper checking when changing default behavior") the cgroup parent usage is unchecked. root will not have a parent and trying to use device.{allow,deny} will cause problems. For some reason my stressing scripts didn't test the root directory so I didn't catch it on my regular tests. Signed-off-by: Aristeu Rozanski <aris@redhat.com> Cc: Li Zefan <lizefan@huawei.com> Cc: James Morris <jmorris@namei.org> Cc: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2012-11-05Merge branch 'cgroup-rmdir-updates' into cgroup/for-3.8Tejun Heo5-336/+156
Pull rmdir updates into for-3.8 so that further callback updates can be put on top. This pull created a trivial conflict between the following two commits. 8c7f6edbda ("cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them") ed95779340 ("cgroup: kill cgroup_subsys->__DEPRECATED_clear_css_refs") The former added a field to cgroup_subsys and the latter removed one from it. They happen to be colocated causing the conflict. Keeping what's added and removing what's removed resolves the conflict. Signed-off-by: Tejun Heo <tj@kernel.org>
2012-11-05cgroup: make ->pre_destroy() return voidTejun Heo5-9/+5
All ->pre_destory() implementations return 0 now, which is the only allowed return value. Make it return void. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Vivek Goyal <vgoyal@redhat.com>
2012-11-05hugetlb: do not fail in hugetlb_cgroup_pre_destroyMichal Hocko1-8/+3
Now that pre_destroy callbacks are called from the context where neither any task can attach the group nor any children group can be added there is no other way to fail from hugetlb_pre_destroy. Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Glauber Costa <glommer@parallels.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2012-11-05memcg: make mem_cgroup_reparent_charges non failingMichal Hocko1-13/+6
Now that pre_destroy callbacks are called from the context where neither any task can attach the group nor any children group can be added there is no other way to fail from mem_cgroup_pre_destroy. mem_cgroup_pre_destroy doesn't have to take a reference to memcg's css because all css' are marked dead already. tj: Remove now unused local variable @cgrp from mem_cgroup_reparent_charges(). Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Glauber Costa <glommer@parallels.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2012-11-05cgroup: remove CGRP_WAIT_ON_RMDIR, cgroup_exclude_rmdir() and ↵Tejun Heo3-95/+1
cgroup_release_and_wakeup_rmdir() CGRP_WAIT_ON_RMDIR is another kludge which was added to make cgroup destruction rollback somewhat working. cgroup_rmdir() used to drain CSS references and CGRP_WAIT_ON_RMDIR and the associated waitqueue and helpers were used to allow the task performing rmdir to wait for the next relevant event. Unfortunately, the wait is visible to controllers too and the mechanism got exposed to memcg by 887032670d ("cgroup avoid permanent sleep at rmdir"). Now that the draining and retries are gone, CGRP_WAIT_ON_RMDIR is unnecessary. Remove it and all the mechanisms supporting it. Note that memcontrol.c changes are essentially revert of 887032670d ("cgroup avoid permanent sleep at rmdir"). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Balbir Singh <bsingharora@gmail.com>
2012-11-05cgroup: deactivate CSS's and mark cgroup dead before invoking ->pre_destroy()Tejun Heo1-46/+19
Because ->pre_destroy() could fail and can't be called under cgroup_mutex, cgroup destruction did something very ugly. 1. Grab cgroup_mutex and verify it can be destroyed; fail otherwise. 2. Release cgroup_mutex and call ->pre_destroy(). 3. Re-grab cgroup_mutex and verify it can still be destroyed; fail otherwise. 4. Continue destroying. In addition to being ugly, it has been always broken in various ways. For example, memcg ->pre_destroy() expects the cgroup to be inactive after it's done but tasks can be attached and detached between #2 and #3 and the conditions that memcg verified in ->pre_destroy() might no longer hold by the time control reaches #3. Now that ->pre_destroy() is no longer allowed to fail. We can switch to the following. 1. Grab cgroup_mutex and verify it can be destroyed; fail otherwise. 2. Deactivate CSS's and mark the cgroup removed thus preventing any further operations which can invalidate the verification from #1. 3. Release cgroup_mutex and call ->pre_destroy(). 4. Re-grab cgroup_mutex and continue destroying. After this change, controllers can safely assume that ->pre_destroy() will only be called only once for a given cgroup and, once ->pre_destroy() is called, the cgroup will stay dormant till it's destroyed. This removes the only reason ->pre_destroy() can fail - new task being attached or child cgroup being created inbetween. Error out path is removed and ->pre_destroy() invocation is open coded in cgroup_rmdir(). v2: cgroup_call_pre_destroy() removal moved to this patch per Michal. Commit message updated per Glauber. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
2012-11-05cgroup: use cgroup_lock_live_group(parent) in cgroup_create()Tejun Heo1-3/+13
This patch makes cgroup_create() fail if @parent is marked removed. This is to prepare for further updates to cgroup_rmdir() path. Note that this change isn't strictly necessary. cgroup can only be created via mkdir and the removed marking and dentry removal happen without releasing cgroup_mutex, so cgroup_create() can never race with cgroup_rmdir(). Even after the scheduled updates to cgroup_rmdir(), cgroup_mkdir() and cgroup_rmdir() are synchronized by i_mutex rendering the added liveliness check unnecessary. Do it anyway such that locking is contained inside cgroup proper and we don't get nasty surprises if we ever grow another caller of cgroup_create(). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-05cgroup: kill CSS_REMOVEDTejun Heo3-29/+15
CSS_REMOVED is one of the several contortions which were necessary to support css reference draining on cgroup removal. All css->refcnts which need draining should be deactivated and verified to equal zero atomically w.r.t. css_tryget(). If any one isn't zero, all refcnts needed to be re-activated and css_tryget() shouldn't fail in the process. This was achieved by letting css_tryget() busy-loop until either the refcnt is reactivated (failed removal attempt) or CSS_REMOVED is set (committing to removal). Now that css refcnt draining is no longer used, there's no need for atomic rollback mechanism. css_tryget() simply can look at the reference count and fail if it's deactivated - it's never getting re-activated. This patch removes CSS_REMOVED and updates __css_tryget() to fail if the refcnt is deactivated. As deactivation and removal are a single step now, they no longer need to be protected against css_tryget() happening from irq context. Remove local_irq_disable/enable() from cgroup_rmdir(). Note that this removes css_is_removed() whose only user is VM_BUG_ON() in memcontrol.c. We can replace it with a check on the refcnt but given that the only use case is a debug assert, I think it's better to simply unexport it. v2: Comment updated and explanation on local_irq_disable/enable() added per Michal Hocko. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
2012-11-05cgroup: kill cgroup_subsys->__DEPRECATED_clear_css_refsTejun Heo2-107/+36
2ef37d3fe4 ("memcg: Simplify mem_cgroup_force_empty_list error handling") removed the last user of __DEPRECATED_clear_css_refs. This patch removes __DEPRECATED_clear_css_refs and mechanisms to support it. * Conditionals dependent on __DEPRECATED_clear_css_refs removed. * cgroup_clear_css_refs() can no longer fail. All that needs to be done are deactivating refcnts, setting CSS_REMOVED and putting the base reference on each css. Remove cgroup_clear_css_refs() and the failure path, and open-code the loops into cgroup_rmdir(). This patch keeps the two for_each_subsys() loops separate while open coding them. They can be merged now but there are scheduled changes which need them to be separate, so keep them separate to reduce the amount of churn. local_irq_save/restore() from cgroup_clear_css_refs() are replaced with local_irq_disable/enable() for simplicity. This is safe as cgroup_rmdir() is always called with IRQ enabled. Note that this IRQ switching is necessary to ensure that css_tryget() isn't called from IRQ context on the same CPU while lower context is between CSS deactivation and setting CSS_REMOVED as css_tryget() would hang forever in such cases waiting for CSS to be re-activated or CSS_REMOVED set. This will go away soon. v2: cgroup_call_pre_destroy() removal dropped per Michal. Commit message updated to explain local_irq_disable/enable() conversion. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com>
2012-11-04Linux 3.7-rc4v3.7-rc4Linus Torvalds1-1/+1
2012-11-04Merge tag 'nfs-for-3.7-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds11-35/+110
Pull NFS client bugfixes from Trond Myklebust: - Fix a bunch of deadlock situations: * State recovery can deadlock if we fail to release sequence ids before scheduling the recovery thread. * Calling deactivate_super() from an RPC workqueue thread can deadlock because of the call to rpc_shutdown_client. - Display the device name correctly in /proc/*/mounts - Fix a number of incorrect error return values: * When NFSv3 mounts fail due to a timeout. * On NFSv4.1 backchannel setup failure * On NFSv4 open access checks - pnfs_find_alloc_layout() must check the layout pointer for NULL - Fix a regression in the legacy DNS resolved * tag 'nfs-for-3.7-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: NFS4: nfs4_opendata_access should return errno NFSv4: Initialise the NFSv4.1 slot table highest_used_slotid correctly SUNRPC: return proper errno from backchannel_rqst NFS: add nfs_sb_deactive_async to avoid deadlock nfs: Show original device name verbatim in /proc/*/mount{s,info} nfsv3: Make v3 mounts fail with ETIMEDOUTs instead EIO on mountd timeouts nfs: Check whether a layout pointer is NULL before free it NFS: fix bug in legacy DNS resolver. NFSv4: nfs4_locku_done must release the sequence id NFSv4.1: We must release the sequence id when we fail to get a session slot NFS: Wait for session recovery to finish before returning
2012-11-04Merge branch 'release' of ↵Linus Torvalds3-6/+9
git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux Pull thermal management & ACPI update from Zhang Rui, Ho humm. Normally these things go through Len. But it's just three small fixes, I guess I can pull directly too. * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: exynos4_tmu_driver_ids should be exynos_tmu_driver_ids. ACPI video: Ignore errors after _DOD evaluation. thermal: solve compilation errors in rcar_thermal
2012-11-04Merge branch 'i2c-embedded/for-current' of ↵Linus Torvalds3-175/+22
git://git.pengutronix.de/git/wsa/linux Pull i2c embedded fixes from Wolfram Sang: "Two patches are usual stuff. The bigger patch is needed to correct a wrong decision made in this merge window. We hoped to get the PIOQUEUE mode in the mxs driver working with DMA, but it turned out to be too broken (leading to data loss), so we now think it is best to remove it entirely and work only with DMA now. The patch should be in 3.7. IMO, so users never get the chance to use both modes in parallel." * 'i2c-embedded/for-current' of git://git.pengutronix.de/git/wsa/linux: i2c: tegra: set irq name as device name i2c-nomadik: Fixup clock handling i2c: mxs: remove broken PIOQUEUE support
2012-11-04Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linuxLinus Torvalds19-92/+275
Pull drm fixes from Dave Airlie: "Scattered selection of fixes: - radeon: load detect fixes from SuSE/AMD - intel: misc i830, sdvo regression, vesafb kickoff ums fix - exynos: maintainers entry update + fixes - udl: fix stride scanout issue it's slightly bigger than I'd probably like, but nothing looked dangerous enough to hold off on." * 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: drm/udl: fix stride issues scanning out stride != width*bpp drm/radeon: add load detection support for ext DAC on R200 (v2) DRM/radeon: For single CRTC GPUs move handling of CRTC_CRT_ON to crtc_dpms(). DRM/Radeon: Fix TV DAC Load Detection for single CRTC chips. DRM/Radeon: Clean up code in TV DAC load detection. drm/radeon: fix ATPX function documentation drivers/gpu/drm/radeon/evergreen_cs.c: Remove unnecessary semicolon DRM/Radeon: On DVI-I use Load Detection when EDID is bogus. DRM/Radeon: Fix primary DAC Load Detection for RV100 chips. DRM/Radeon: Fix Load Detection on legacy primary DAC. drm: exynos: removed warning due to missing typecast for mixer driver data drm/exynos: add support for ARCH_MULTIPLATFORM MAINTAINERS: Add git repository for Exynos DRM drm/exynos: fix display on issue drm/i915: Only kick out vesafb if we takeover the fbcon with KMS drm/i915: be less verbose about inability to provide vendor backlight drm/i915: clear the entire sdvo infoframe buffer drm/i915: VGA needs to be on pipe A on i830M drm/i915: fix overlay on i830M
2012-11-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds27-129/+320
Pull networking fixes from David Miller: "First post-Sandy pull request" 1) Fix antenna gain handling and initialization of chan->max_reg_power in wireless, from Felix Fietkau. 2) Fix nexthop handling in H.232 conntrack helper, from Julian Anastasov. 3) Only process 80211 mesh config header in certain kinds of frames, from Javier Cardona. 4) 80211 management frame header length needs to be validated, from Johannes Berg. 5) Don't access free'd SKBs in ath9k driver, from Felix Fietkay. 6) Test for permanent state correctly in VXLAN driver, from Stephen Hemminger. 7) BNX2X bug fixes from Yaniv Rosner and Dmitry Kravkov. 8) Fix off by one errors in bonding, from Nikolay ALeksandrov. 9) Fix divide by zero in TCP-Illinois congestion control. From Jesper Dangaard Brouer. 10) TCP metrics code says "Yo dawg, I heard you like sizeof, so I did a sizeof of a sizeof, so you can size your size" Fix from Julian Anastasov. 11) Several drivers do mdiobus_free without first doing an mdiobus_unregister leading to stray pointer references. Fix from Peter Senna Tschudin. 12) Fix OOPS in l2tp_eth_create() error path, it's another danling pointer kinda situation. Fix from Tom Parkin. 13) Hardware driven by the vmxnet driver can't handle larger than 16K fragments, so split them up when necessary. From Eric Dumazet. 14) Handle zero length data length in tcp_send_rcvq() properly. Fix from Pavel Emelyanov. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (38 commits) tcp-repair: Handle zero-length data put in rcv queue vmxnet3: must split too big fragments l2tp: fix oops in l2tp_eth_create() error path cxgb4: Fix unable to get UP event from the LLD drivers/net/phy/mdio-bitbang.c: Call mdiobus_unregister before mdiobus_free drivers/net/ethernet/nxp/lpc_eth.c: Call mdiobus_unregister before mdiobus_free bnx2x: fix HW initialization using fw 7.8.x tcp: Fix double sizeof in new tcp_metrics code net: fix divide by zero in tcp algorithm illinois net: sctp: Fix typo in net/sctp bonding: fix second off-by-one error bonding: fix off-by-one error bnx2x: Disable FCoE for 57840 since not yet supported by FW bnx2x: Fix no link on 577xx 10G-baseT bnx2x: Fix unrecognized SFP+ module after driver is loaded bnx2x: Fix potential incorrect link speed provision bnx2x: Restore global registers back to default. bnx2x: Fix link down in 57712 following LFA bnx2x: Fix 57810 1G-KR link against certain switches. ixgbe: PTP get_ts_info missing software support ...
2012-11-03tcp-repair: Handle zero-length data put in rcv queuePavel Emelyanov1-0/+3
When sending data into a tcp socket in repair state we should check for the amount of data being 0 explicitly. Otherwise we'll have an skb with seq == end_seq in rcv queue, but tcp doesn't expect this to happen (in particular a warn_on in tcp_recvmsg shoots). Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Reported-by: Giorgos Mavrikas <gmavrikas@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-03vmxnet3: must split too big fragmentsEric Dumazet1-20/+45
vmxnet3 has a 16Kbytes limit per tx descriptor, that happened to work as long as we provided PAGE_SIZE fragments. Our stack can now build larger fragments, so we need to split them to the 16kbytes boundary. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: jongman heo <jongman.heo@samsung.com> Tested-by: jongman heo <jongman.heo@samsung.com> Cc: Shreyas Bhatewara <sbhatewara@vmware.com> Reviewed-by: Bhavesh Davda <bhavesh@vmware.com> Signed-off-by: Shreyas Bhatewara <sbhatewara@vmware.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-03l2tp: fix oops in l2tp_eth_create() error pathTom Parkin1-0/+1
When creating an L2TPv3 Ethernet session, if register_netdev() should fail for any reason (for example, automatic naming for "l2tpeth%d" interfaces hits the 32k-interface limit), the netdev is freed in the error path. However, the l2tp_eth_sess structure's dev pointer is left uncleared, and this results in l2tp_eth_delete() then attempting to unregister the same netdev later in the session teardown. This results in an oops. To avoid this, clear the session dev pointer in the error path. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-03exynos4_tmu_driver_ids should be exynos_tmu_driver_ids.Jonghwan Choi1-1/+1
Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com> Reviewed-by: Amit Daniel Kachhap <amit.kachhap@linaro.org> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2012-11-03ACPI video: Ignore errors after _DOD evaluation.Igor Murzov1-4/+7
There are systems where video module known to work fine regardless of broken _DOD and ignoring returned value here doesn't cause any issues later. This should fix brightness controls on some laptops. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=47861 Signed-off-by: Igor Murzov <e-mail@date.by> Reviewed-by: Sergey V <sftp.mtuci@gmail.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>