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* Merge tag 'vfio-v3.15-rc1' of git://github.com/awilliam/linux-vfioLinus Torvalds2014-04-036-308/+390
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull VFIO updates from Alex Williamson: "VFIO updates for v3.15 include: - Allow the vfio-type1 IOMMU to support multiple domains within a container - Plumb path to query whether all domains are cache-coherent - Wire query into kvm-vfio device to avoid KVM x86 WBINVD emulation - Always select CONFIG_ANON_INODES, vfio depends on it (Arnd) The first patch also makes the vfio-type1 IOMMU driver completely independent of the bus_type of the devices it's handling, which enables it to be used for both vfio-pci and a future vfio-platform (and hopefully combinations involving both simultaneously)" * tag 'vfio-v3.15-rc1' of git://github.com/awilliam/linux-vfio: vfio: always select ANON_INODES kvm/vfio: Support for DMA coherent IOMMUs vfio: Add external user check extension interface vfio/type1: Add extension to test DMA cache coherence of IOMMU vfio/iommu_type1: Multi-IOMMU domain support
| * vfio: always select ANON_INODESArnd Bergmann2014-03-271-0/+1
| | | | | | | | | | | | | | | | | | The vfio code cannot be built when CONFIG_ANON_INODES is disabled, so this enforces the symbol to be enabled through Kconfig. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
| * kvm/vfio: Support for DMA coherent IOMMUsAlex Williamson2014-02-261-7/+20
| | | | | | | | | | | | | | | | | | | | | | | | VFIO now has support for using the IOMMU_CACHE flag and a mechanism for an external user to test the current operating mode of the IOMMU. Add support for this to the kvm-vfio pseudo device so that we only register noncoherent DMA when necessary. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
| * vfio: Add external user check extension interfaceAlex Williamson2014-02-262-0/+8
| | | | | | | | | | | | | | This lets us check extensions, particularly VFIO_DMA_CC_IOMMU using the external user interface, allowing KVM to probe IOMMU coherency. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
| * vfio/type1: Add extension to test DMA cache coherence of IOMMUAlex Williamson2014-02-262-0/+26
| | | | | | | | | | | | | | | | Now that the type1 IOMMU backend can support IOMMU_CACHE, we need to be able to test whether coherency is currently enforced. Add an extension for this. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
| * vfio/iommu_type1: Multi-IOMMU domain supportAlex Williamson2014-02-262-302/+336
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We currently have a problem that we cannot support advanced features of an IOMMU domain (ex. IOMMU_CACHE), because we have no guarantee that those features will be supported by all of the hardware units involved with the domain over its lifetime. For instance, the Intel VT-d architecture does not require that all DRHDs support snoop control. If we create a domain based on a device behind a DRHD that does support snoop control and enable SNP support via the IOMMU_CACHE mapping option, we cannot then add a device behind a DRHD which does not support snoop control or we'll get reserved bit faults from the SNP bit in the pagetables. To add to the complexity, we can't know the properties of a domain until a device is attached. We could pass this problem off to userspace and require that a separate vfio container be used, but we don't know how to handle page accounting in that case. How do we know that a page pinned in one container is the same page as a different container and avoid double billing the user for the page. The solution is therefore to support multiple IOMMU domains per container. In the majority of cases, only one domain will be required since hardware is typically consistent within a system. However, this provides us the ability to validate compatibility of domains and support mixed environments where page table flags can be different between domains. To do this, our DMA tracking needs to change. We currently try to coalesce user mappings into as few tracking entries as possible. The problem then becomes that we lose granularity of user mappings. We've never guaranteed that a user is able to unmap at a finer granularity than the original mapping, but we must honor the granularity of the original mapping. This coalescing code is therefore removed, allowing only unmaps covering complete maps. The change in accounting is fairly small here, a typical QEMU VM will start out with roughly a dozen entries, so it's arguable if this coalescing was ever needed. We also move IOMMU domain creation to the point where a group is attached to the container. An interesting side-effect of this is that we now have access to the device at the time of domain creation and can probe the devices within the group to determine the bus_type. This finally makes vfio_iommu_type1 completely device/bus agnostic. In fact, each IOMMU domain can host devices on different buses managed by different physical IOMMUs, and present a single DMA mapping interface to the user. When a new domain is created, mappings are replayed to bring the IOMMU pagetables up to the state of the current container. And of course, DMA mapping and unmapping automatically traverse all of the configured IOMMU domains. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Cc: Varun Sethi <Varun.Sethi@freescale.com>
* | Merge tag 'stable/for-linus-3.15-tag' of ↵Linus Torvalds2014-04-0320-191/+265
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen features and fixes from David Vrabel: "Support PCI devices with multiple MSIs, performance improvement for kernel-based backends (by not populated m2p overrides when mapping), and assorted minor bug fixes and cleanups" * tag 'stable/for-linus-3.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/acpi-processor: fix enabling interrupts on syscore_resume xen/grant-table: Refactor gnttab_[un]map_refs to avoid m2p_override xen: remove XEN_PRIVILEGED_GUEST xen: add support for MSI message groups xen-pciback: Use pci_enable_msix_exact() instead of pci_enable_msix() xen/xenbus: remove unused xenbus_bind_evtchn() xen/events: remove unnecessary call to bind_evtchn_to_cpu() xen/events: remove the unused resend_irq_on_evtchn() drivers:xen-selfballoon:reset 'frontswap_inertia_counter' after frontswap_shrink drivers: xen: Include appropriate header file in pcpu.c drivers: xen: Mark function as static in platform-pci.c
| * | xen/acpi-processor: fix enabling interrupts on syscore_resumeStanislaw Gruszka2014-03-183-7/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | syscore->resume() callback is expected to do not enable interrupts, it generates warning like below otherwise: [ 9386.365390] WARNING: CPU: 0 PID: 6733 at drivers/base/syscore.c:104 syscore_resume+0x9a/0xe0() [ 9386.365403] Interrupts enabled after xen_acpi_processor_resume+0x0/0x34 [xen_acpi_processor] ... [ 9386.365429] Call Trace: [ 9386.365434] [<ffffffff81667a8b>] dump_stack+0x45/0x56 [ 9386.365437] [<ffffffff8106921d>] warn_slowpath_common+0x7d/0xa0 [ 9386.365439] [<ffffffff8106928c>] warn_slowpath_fmt+0x4c/0x50 [ 9386.365442] [<ffffffffa0261bb0>] ? xen_upload_processor_pm_data+0x300/0x300 [xen_acpi_processor] [ 9386.365443] [<ffffffff814055fa>] syscore_resume+0x9a/0xe0 [ 9386.365445] [<ffffffff810aef42>] suspend_devices_and_enter+0x402/0x470 [ 9386.365447] [<ffffffff810af128>] pm_suspend+0x178/0x260 On xen_acpi_processor_resume() we call various procedures, which are non atomic and can enable interrupts. To prevent the issue introduce separate resume notify called after we enable interrupts on resume and before we call other drivers resume callbacks. Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen/grant-table: Refactor gnttab_[un]map_refs to avoid m2p_overrideZoltan Kiss2014-03-185-96/+156
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The grant mapping API does m2p_override unnecessarily: only gntdev needs it, for blkback and future netback patches it just cause a lock contention, as those pages never go to userspace. Therefore this series does the following: - the bulk of the original function (everything after the mapping hypercall) is moved to arch-dependent set/clear_foreign_p2m_mapping - the "if (xen_feature(XENFEAT_auto_translated_physmap))" branch goes to ARM - therefore the ARM function could be much smaller, the m2p_override stubs could be also removed - on x86 the set_phys_to_machine calls were moved up to this new funcion from m2p_override functions - and m2p_override functions are only called when there is a kmap_ops param It also removes a stray space from arch/x86/include/asm/xen/page.h. Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Suggested-by: Anthony Liguori <aliguori@amazon.com> Suggested-by: David Vrabel <david.vrabel@citrix.com> Suggested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
| * | xen: remove XEN_PRIVILEGED_GUESTMichael Opdenacker2014-03-181-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes the Kconfig symbol XEN_PRIVILEGED_GUEST which is used nowhere in the tree. We do know grub2 has a script that greps kernel configuration files for its macro. It shouldn't do that. As Linus summarized: This is a grub bug. It really is that simple. Treat it as one. Besides, grub2's grepping for that macro is actually superfluous. See, that script currently contains this test (simplified): grep -x CONFIG_XEN_DOM0=y $config || grep -x CONFIG_XEN_PRIVILEGED_GUEST=y $config But since XEN_DOM0 and XEN_PRIVILEGED_GUEST are by definition equal, removing XEN_PRIVILEGED_GUEST cannot influence this test. So there's no reason to not remove this symbol, like we do with all unused Kconfig symbols. [pebolle@tiscali.nl: rewrote commit explanation.] Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com> Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | xen: add support for MSI message groupsRoger Pau Monne2014-03-185-27/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for MSI message groups for Xen Dom0 using the MAP_PIRQ_TYPE_MULTI_MSI pirq map type. In order to keep track of which pirq is the first one in the group all pirqs in the MSI group except for the first one have the newly introduced PIRQ_MSI_GROUP flag set. This prevents calling PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the first pirq in the group. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * | xen-pciback: Use pci_enable_msix_exact() instead of pci_enable_msix()Alexander Gordeev2014-02-281-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As result of deprecation of MSI-X/MSI enablement functions pci_enable_msix() and pci_enable_msi_block() all drivers using these two interfaces need to be updated to use the new pci_enable_msi_range() or pci_enable_msi_exact() and pci_enable_msix_range() or pci_enable_msix_exact() interfaces. Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: linux-pci@vger.kernel.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * | xen/xenbus: remove unused xenbus_bind_evtchn()David Vrabel2014-02-282-28/+0
| | | | | | | | | | | | | | | | | | | | | | | | xenbus_bind_evtchn() has no callers so remove it. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * | xen/events: remove unnecessary call to bind_evtchn_to_cpu()David Vrabel2014-02-281-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | Since bind_evtchn_to_cpu() is always called after an event channel is bound, there is no need to call it after closing an event channel. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * | xen/events: remove the unused resend_irq_on_evtchn()David Vrabel2014-02-282-22/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | resend_irq_on_evtchn() was only used by ia64 (which no longer has Xen support). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * | drivers:xen-selfballoon:reset 'frontswap_inertia_counter' after frontswap_shrinkBob Liu2014-02-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I looked at this issue https://lkml.org/lkml/2013/11/21/158, I found that frontswap_selfshrink() doesn't work as expected sometimes. Pages are continuously added to frontswap and gotten back soon. It's a waste of cpu time and increases the memory pressue of Guest OS. Take an example. First time in frontswap_selfshrink(): 1. last_frontswap_pages = cur_frontswap_pages = 0 2. cur_frontswap_pages = frontswap_curr_pages() = 100 When 'frontswap_inertia_counter' decreased to 0: 1. last_frontswap_pages = cur_frontswap_pages = 100 2. cur_frontswap_pages = frontswap_curr_pages() = 100 3. call frontswap_shrink() and let's assumption that 10 pages are gotten back from frontswap. 4. now frontswap_curr_pages() is 90. If then memory is not enough in Guest OS and 9 more pages(smaller than gotten back) added to frontswap. Now frontswap_curr_pages() is 99 and we don't expect to get back more pages from frontswap because geust os is under memory pressure. But next time in frontswap_selfshrink(): 1. last_frontswap_pages is set to the old value of cur_frontswap_pages(still 100) 2. cur_frontswap_pages(99) is still smaller than last_frontswap_pages. 3. call frontswap_shrink() and continue to get back pages from frontswap!! Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * | drivers: xen: Include appropriate header file in pcpu.cRashika Kheria2014-02-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Include appropriate header file in xen/pcpu.c because include/xen/acpi.h contains prototype declaration of functions defined in the file. This eliminates the following warning in xen/pcpu.c: drivers/xen/pcpu.c:336:6: warning: no previous prototype for ‘xen_pcpu_hotplug_sync’ [-Wmissing-prototypes] drivers/xen/pcpu.c:346:5: warning: no previous prototype for ‘xen_pcpu_id’ [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
| * | drivers: xen: Mark function as static in platform-pci.cRashika Kheria2014-02-281-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | Mark function as static in xen/platform-pci.c because it is not used outside this file. This eliminates the following warning in xen/platform-pci.c: drivers/xen/platform-pci.c:48:15: warning: no previous prototype for ‘alloc_xen_mmio’ [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
* | Merge branch 'for-3.15' of ↵Linus Torvalds2014-04-0332-2734/+1908
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "A lot updates for cgroup: - The biggest one is cgroup's conversion to kernfs. cgroup took after the long abandoned vfs-entangled sysfs implementation and made it even more convoluted over time. cgroup's internal objects were fused with vfs objects which also brought in vfs locking and object lifetime rules. Naturally, there are places where vfs rules don't fit and nasty hacks, such as credential switching or lock dance interleaving inode mutex and cgroup_mutex with object serial number comparison thrown in to decide whether the operation is actually necessary, needed to be employed. After conversion to kernfs, internal object lifetime and locking rules are mostly isolated from vfs interactions allowing shedding of several nasty hacks and overall simplification. This will also allow implmentation of operations which may affect multiple cgroups which weren't possible before as it would have required nesting i_mutexes. - Various simplifications including dropping of module support, easier cgroup name/path handling, simplified cgroup file type handling and task_cg_lists optimization. - Prepatory changes for the planned unified hierarchy, which is still a patchset away from being actually operational. The dummy hierarchy is updated to serve as the default unified hierarchy. Controllers which aren't claimed by other hierarchies are associated with it, which BTW was what the dummy hierarchy was for anyway. - Various fixes from Li and others. This pull request includes some patches to add missing slab.h to various subsystems. This was triggered xattr.h include removal from cgroup.h. cgroup.h indirectly got included a lot of files which brought in xattr.h which brought in slab.h. There are several merge commits - one to pull in kernfs updates necessary for converting cgroup (already in upstream through driver-core), others for interfering changes in the fixes branch" * 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (74 commits) cgroup: remove useless argument from cgroup_exit() cgroup: fix spurious lockdep warning in cgroup_exit() cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.c cgroup: break kernfs active_ref protection in cgroup directory operations cgroup: fix cgroup_taskset walking order cgroup: implement CFTYPE_ONLY_ON_DFL cgroup: make cgrp_dfl_root mountable cgroup: drop const from @buffer of cftype->write_string() cgroup: rename cgroup_dummy_root and related names cgroup: move ->subsys_mask from cgroupfs_root to cgroup cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebinding cgroup: remove NULL checks from [pr_cont_]cgroup_{name|path}() cgroup: use cgroup_setup_root() to initialize cgroup_dummy_root cgroup: reorganize cgroup bootstrapping cgroup: relocate setting of CGRP_DEAD cpuset: use rcu_read_lock() to protect task_cs() cgroup_freezer: document freezer_fork() subtleties cgroup: update cgroup_transfer_tasks() to either succeed or fail cgroup: drop task_lock() protection around task->cgroups cgroup: update how a newly forked task gets associated with css_set ...
| * | cgroup: remove useless argument from cgroup_exit()Li Zefan2014-03-293-6/+5
| | | | | | | | | | | | | | | Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: fix spurious lockdep warning in cgroup_exit()Li Zefan2014-03-292-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_exit() is called in fork and exit path. If it's called in the failure path during fork, PF_EXITING isn't set, and then lockdep will complain. Fix this by removing cgroup_exit() in that failure path. cgroup_fork() does nothing that needs cleanup. Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.cMonam Agarwal2014-03-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL) The rcu_assign_pointer() ensures that the initialization of a structure is carried out before storing a pointer to that structure. And in the case of the NULL pointer, there is no structure to initialize. So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL) Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: break kernfs active_ref protection in cgroup directory operationsTejun Heo2014-03-201-1/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_tree_mutex should nest above the kernfs active_ref protection; however, cgroup_create() and cgroup_rename() were grabbing cgroup_tree_mutex while under kernfs active_ref protection. This has actualy possibility to lead to deadlocks in case these operations race against cgroup_rmdir() which invokes kernfs_remove() on directory kernfs_node while holding cgroup_tree_mutex. Neither cgroup_create() or cgroup_rename() requires active_ref protection. The former already has enough synchronization through cgroup_lock_live_group() and the latter doesn't care, so this can be fixed by updating both functions to break all active_ref protections before grabbing cgroup_tree_mutex. While this patch fixes the immediate issue, it probably needs further work in the long term - kernfs directories should enable lockdep annotations and maybe the better way to handle this is marking directory nodes as not needing active_ref protection rather than breaking it in each operation. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | cgroup: fix cgroup_taskset walking orderTejun Heo2014-03-191-5/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_taskset is used to track and iterate target tasks while migrating a task or process and should guarantee that the first task iterated is the task group leader if a process is being migrated. b3dc094e9390 ("cgroup: use css_set->mg_tasks to track target tasks during migration") replaced flex array cgroup_taskset->tc_array with css_set->mg_tasks list to remove process size limit and dynamic allocation during migration; unfortunately, it incorrectly used list operations which don't preserve order breaking the guarantee that cgroup_taskset_first() returns the leader for a process target. Fix it by using order preserving list operations. Note that as multiple src_csets may map to a single dst_cset, the iteration order may change across cgroup_task_migrate(); however, the leader is still guaranteed to be the first entry. The switch to list_splice_tail_init() at the end of cgroup_migrate() isn't strictly necessary. Let's still do it for consistency. Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: implement CFTYPE_ONLY_ON_DFLTejun Heo2014-03-192-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | This cftype flag makes the file only appear on the default hierarchy. This will later be used for cgroup.controllers file. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: make cgrp_dfl_root mountableTejun Heo2014-03-192-33/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgrp_dfl_root will be used as the default unified hierarchy. This patch makes cgrp_dfl_root mountable by making the following changes. * cgroup_init_early() now initializes cgrp_dfl_root w/ CGRP_ROOT_SANE_BEHAVIOR. The default hierarchy is always sane. * parse_cgroupfs_options() and cgroup_mount() are updated such that cgrp_dfl_root is mounted if sane_behavior is specified w/o any subsystems. * rebind_subsystems() now populates the root directory of cgrp_dfl_root. Note that the function still guarantees success of rebinding subsystems to cgrp_dfl_root. If populating fails while rebinding to cgrp_dfl_root, it whines but ignores the error. * For backward compatibility, the default hierarchy shows up in /proc/$PID/cgroup only after it's explicitly mounted so that userland which doesn't make use of it doesn't see any change. * "current_css_set_cg_links" file of debug cgroup now treats the default hierarchy the same as other hierarchies. This is visible to userland. Given that it's for debug controller, this should be fine. * While at it, implement cgroup_on_dfl() which tests whether a give cgroup is on the default hierarchy or not. The above changes make cgrp_dfl_root mostly equivalent to other controllers but the actual unified hierarchy behaviors are not implemented yet. Let's plug child cgroup creation in cgrp_dfl_root from create_cgroup() for now. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: drop const from @buffer of cftype->write_string()Tejun Heo2014-03-1911-15/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cftype->write_string() just passes on the writeable buffer from kernfs and there's no reason to add const restriction on the buffer. The only thing const achieves is unnecessarily complicating parsing of the buffer. Drop const from @buffer. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: 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>
| * | cgroup: rename cgroup_dummy_root and related namesTejun Heo2014-03-192-94/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dummy root will be repurposed to serve as the default unified hierarchy. Let's rename things in preparation. * s/cgroup_dummy_root/cgrp_dfl_root/ * s/cgroupfs_root/cgroup_root/ as we don't do fs part directly anymore * s/cgroup_root->top_cgroup/cgroup_root->cgrp/ for brevity This is pure rename. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: move ->subsys_mask from cgroupfs_root to cgroupTejun Heo2014-03-192-25/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroupfs_root->subsys_mask represents the controllers attached to the hierarchy. This patch moves the field to cgroup. Subsystem initialization and rebinding updates the top cgroup's subsys_mask. For !root cgroups, the subsys_mask bits are set from create_css() and cleared from kill_css(), which effectively means that all cgroups will have the same subsys_mask as the top cgroup. While this doesn't make any difference now, this will help implementation of the default unified hierarchy where !root cgroups may have subsets of the top_cgroup's subsys_mask. While at it, __kill_css() is split out of kill_css(). The former doesn't care about the subsys_mask while the latter becomes noop if the controller is already killed and clears the matching bit if not before proceeding to killing the css. This will be used later by the default unified hierarchy implementation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebindingTejun Heo2014-03-191-44/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, while rebinding, cgroup_dummy_root serves as the anchor point. In addition to the target root, rebind_subsystems() takes @added_mask and @removed_mask. The subsystems specified in the former are expected to be on the dummy root and then moved to the target root. The ones in the latter are moved from non-dummy root to dummy. Now that the dummy root is a fully functional one and we're planning to use it for the default unified hierarchy, this level of distinction between dummy and non-dummy roots is quite awkward. This patch updates rebind_subsystems() to take the target root and one subsystem mask and move the specified subsystmes to the target root which may or may not be the dummy root. IOW, unbinding now becomes moving the subsystems to the dummy root and binding to non-dummy root. This makes the dummy root mostly equivalent to other hierarchies in terms of the mechanism of moving subsystems around; however, we still retain all the semantical restrictions so that this patch doesn't introduce any visible behavior differences. Another noteworthy detail is that rebind_subsystems() guarantees that moving a subsystem to the dummy root never fails so that valid unmounting attempts always succeed. This unifies binding and unbinding of subsystems. The invocation points of ->bind() were inconsistent between the two and now moved after whole rebinding is complete. This doesn't break the current users and generally makes more sense. All rebind_subsystems() users are converted accordingly. Note that cgroup_remount() now makes two calls to rebind_subsystems() to bind and then unbind the requested subsystems. This will allow repurposing of the dummy hierarchy as the default unified hierarchy and shouldn't make any userland visible behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: remove NULL checks from [pr_cont_]cgroup_{name|path}()Tejun Heo2014-03-191-20/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | The dummy hierarchy is now a fully functional one and dummy_top has a kernfs_node associated with it. Drop the NULL checks in [pr_cont_]cont_{name|path}() which are no longer necessary. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: use cgroup_setup_root() to initialize cgroup_dummy_rootTejun Heo2014-03-191-23/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_dummy_root is used to host controllers which aren't attached to any other hierarchy. The root is minimally set up during kernfs bootstrap and didn't go through full hierarchy initialization. We're planning to use cgroup_dummy_root for the default unified hierarchy and thus want it to be fully functional. Replace the special initialization, which was collected into cgroup_init() by the previous patch, with an invocation of cgroup_setup_root(). This simplifies the init path and makes cgroup_dummy_root a full hierarchy with its own kernfs_root and all. As this puts the dummy hierarchy on the cgroup_roots list, rename for_each_active_root() to for_each_root() and update its users to skip the dummy root for now. This patch doesn't cause any userland visible behavior changes at this point. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: reorganize cgroup bootstrappingTejun Heo2014-03-191-51/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Fields of init_css_set and css_set_count are now set using initializer instead of programmatically from cgroup_init_early(). * init_cgroup_root() now also takes @opts and performs the optional part of initialization too. The leftover part of cgroup_root_from_opts() is collapsed into its only caller - cgroup_mount(). * Initialization of cgroup_root_count and linking of init_css_set are moved from cgroup_init_early() to to cgroup_init(). None of the early_init users depends on init_css_set being linked. * Subsystem initializations are moved after dummy hierarchy init and init_css_set linking. These changes reorganize the bootstrap logic so that the dummy hierarchy can share the usual hierarchy init path and be made more normal. These changes don't make noticeable behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: relocate setting of CGRP_DEADTejun Heo2014-03-191-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In cgroup_destroy_locked(), move setting of CGRP_DEAD above invocations of kill_css(). This doesn't make any visible behavior difference now but will be used to inhibit manipulating controller enable states of a dying cgroup on the unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cpuset: use rcu_read_lock() to protect task_cs()Li Zefan2014-03-031-11/+13
| | | | | | | | | | | | | | | | | | | | | | | | We no longer use task_lock() to protect tsk->cgroups. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup_freezer: document freezer_fork() subtletiesTejun Heo2014-02-251-3/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_subsys->fork() callback is special in that it's called outside the usual cgroup locking and may race with on-going migration. freezer_fork() currently doesn't consider such race condition; however, it is still correct thanks to the fact that freeze_task() may be called spuriously. This is quite subtle. Let's explain what's going on and add test to detect racing and losing to task migration and skip freeze_task() in such cases for documentation. This doesn't make any behavior difference meaningful to userland. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
| * | cgroup: update cgroup_transfer_tasks() to either succeed or failTejun Heo2014-02-251-5/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_transfer_tasks() can currently fail in the middle due to memory allocation failure. When that happens, the function just aborts and returns error code and there's no way to tell how many actually got migrated at the point of failure and or to revert the partial migration. Update it to use cgroup_migrate{_add_src|prepare_dst|migrate|finish}() so that the function either succeeds or fails as a whole as long as ->can_attach() doesn't fail. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: drop task_lock() protection around task->cgroupsTejun Heo2014-02-252-75/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For optimization, task_lock() is additionally used to protect task->cgroups. The optimization is pretty dubious as either css_set_rwsem is grabbed anyway or PF_EXITING already protects task->cgroups. It adds only overhead and confusion at this point. Let's drop task_[un]lock() and update comments accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: update how a newly forked task gets associated with css_setTejun Heo2014-02-251-31/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a new process is forked, cgroup_fork() associates it with the css_set of its parent but doesn't link it into it. After the new process is linked to tasklist, cgroup_post_fork() does the linking. This is problematic for cgroup_transfer_tasks() as there's no way to tell whether there are tasks which are pointing to a css_set but not linked yet. It is impossible to implement an operation which transfer all tasks of a cgroup to another and the current cgroup_transfer_tasks() can easily be tricked into leaving a newly forked process behind if it gets called between cgroup_fork() and cgroup_post_fork(). Let's make association with a css_set and linking atomic by moving it to cgroup_post_fork(). cgroup_fork() sets child->cgroups to init_css_set as a placeholder and cgroup_post_fork() is updated to perform both the association with the parent's cgroup and linking there. This means that a newly created task will point to init_css_set without holding a ref to it much like what it does on the exit path. Empty cg_list is used to indicate that the task isn't holding a ref to the associated css_set. This fixes an actual bug with cgroup_transfer_tasks(); however, I'm not marking it for -stable. The whole thing is broken in multiple other ways which require invasive updates to fix and I don't think it's worthwhile to bother with backporting this particular one. Fortunately, the only user is cpuset and these bugs don't crash the machine. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: split process / task migration into four stepsTejun Heo2014-02-252-59/+182
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, process / task migration is a single operation which may fail depending on memory pressure or the involved controllers' ->can_attach() callbacks. One problem with this approach is migration of multiple targets. It's impossible to tell whether a given target will be successfully migrated beforehand and cgroup core can't keep track of enough states to roll back after intermediate failure. This is already an issue with cgroup_transfer_tasks(). Also, we're gonna need multiple target migration for unified hierarchy. This patch splits migration into four stages - cgroup_migrate_add_src(), cgroup_migrate_prepare_dst(), cgroup_migrate() and cgroup_migrate_finish(), where cgroup_migrate_prepare_dst() performs all the operations which may fail due to allocation failure without actually migrating the target. The four separate stages mean that, disregarding ->can_attach() failures, the success or failure of multi target migration can be determined before performing any actual migration. If preparations of all targets succeed, the whole thing will succeed. If not, the whole operation can fail without any side-effect. Since the previous patch to use css_set->mg_tasks to keep track of migration targets, the only thing which may need memory allocation during migration is the target css_sets. cgroup_migrate_prepare() pins all source and target css_sets and link them up. Note that this can be performed without holding threadgroup_lock even if the target is a process. As long as cgroup_mutex is held, no new css_set can be put into play. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: separate out cset_group_from_root() from task_cgroup_from_root()Tejun Heo2014-02-251-12/+17
| | | | | | | | | | | | | | | | | | | | | This will be used by the planned migration path update. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: use css_set->mg_tasks to track target tasks during migrationTejun Heo2014-02-252-108/+131
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, while migrating tasks from one cgroup to another, cgroup_attach_task() builds a flex array of all target tasks; unfortunately, this has a couple issues. * Flex array has size limit. On 64bit, struct task_and_cgroup is 24bytes making the flex element limit around 87k. It is a high number but not impossible to hit. This means that the current cgroup implementation can't migrate a process with more than 87k threads. * Process migration involves memory allocation whose size is dependent on the number of threads the process has. This means that cgroup core can't guarantee success or failure of multi-process migrations as memory allocation failure can happen in the middle. This is in part because cgroup can't grab threadgroup locks of multiple processes at the same time, so when there are multiple processes to migrate, it is imposible to tell how many tasks are to be migrated beforehand. Note that this already affects cgroup_transfer_tasks(). cgroup currently cannot guarantee atomic success or failure of the operation. It may fail in the middle and after such failure cgroup doesn't have enough information to roll back properly. It just aborts with some tasks migrated and others not. To resolve the situation, this patch updates the migration path to use task->cg_list to track target tasks. The previous patch already added css_set->mg_tasks and updated iterations in non-migration paths to include them during task migration. This patch updates migration path to actually make use of it. Instead of putting onto a flex_array, each target task is moved from its css_set->tasks list to css_set->mg_tasks and the migration path keeps trace of all the source css_sets and the associated cgroups. Once all source css_sets are determined, the destination css_set for each is determined, linked to the matching source css_set and put on a separate list. To iterate the target tasks, migration path just needs to iterat through either the source or target css_sets, depending on whether migration has been committed or not, and the tasks on their ->mg_tasks lists. cgroup_taskset is updated to contain the list_heads for source and target css_sets and the iteration cursor. cgroup_taskset_*() are accordingly updated to walk through css_sets and their ->mg_tasks. This resolves the above listed issues with moderate additional complexity. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | cgroup: add css_set->mg_tasksTejun Heo2014-02-252-21/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, while migrating tasks from one cgroup to another, cgroup_attach_task() builds a flex array of all target tasks; unfortunately, this has a couple issues. * Flex array has size limit. On 64bit, struct task_and_cgroup is 24bytes making the flex element limit around 87k. It is a high number but not impossible to hit. This means that the current cgroup implementation can't migrate a process with more than 87k threads. * Process migration involves memory allocation whose size is dependent on the number of threads the process has. This means that cgroup core can't guarantee success or failure of multi-process migrations as memory allocation failure can happen in the middle. This is in part because cgroup can't grab threadgroup locks of multiple processes at the same time, so when there are multiple processes to migrate, it is imposible to tell how many tasks are to be migrated beforehand. Note that this already affects cgroup_transfer_tasks(). cgroup currently cannot guarantee atomic success or failure of the operation. It may fail in the middle and after such failure cgroup doesn't have enough information to roll back properly. It just aborts with some tasks migrated and others not. To resolve the situation, we're going to use task->cg_list during migration too. Instead of building a separate array, target tasks will be linked into a dedicated migration list_head on the owning css_set. Tasks on the migration list are treated the same as tasks on the usual tasks list; however, being on a separate list allows cgroup migration code path to keep track of the target tasks by simply keeping the list of css_sets with tasks being migrated, making unpredictable dynamic allocation unnecessary. In prepartion of such migration path update, this patch introduces css_set->mg_tasks list and updates css_set task iterations so that they walk both css_set->tasks and ->mg_tasks. Note that ->mg_tasks isn't used yet. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | Merge branch 'cgroup/for-3.14-fixes' into cgroup/for-3.15Tejun Heo2014-02-251-6/+6
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull in for-3.14-fixes to receive 532de3fc72ad ("cgroup: update cgroup_enable_task_cg_lists() to grab siglock") which conflicts with afeb0f9fd425 ("cgroup: relocate cgroup_enable_task_cg_lists()") and the following cg_lists updates. This is likely to cause further conflicts down the line too, so let's merge it early. As cgroup_enable_task_cg_lists() is relocated in for-3.15, this merge causes conflict in the original position. It's resolved by applying siglock changes to the updated version in the new location. Conflicts: kernel/cgroup.c Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | cgroup: add a validation check to cgroup_add_cftyps()Li Zefan2014-02-181-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fengguang reported this bug: BUG: unable to handle kernel NULL pointer dereference at 0000003c IP: [<cc90b4ad>] cgroup_cfts_commit+0x27/0x1c1 ... Call Trace: [<cc9d1129>] ? kmem_cache_alloc_trace+0x33f/0x3b7 [<cc90c6fc>] cgroup_add_cftypes+0x8f/0xca [<cd78b646>] cgroup_init+0x6a/0x26a [<cd764d7d>] start_kernel+0x4d7/0x57a [<cd7642ef>] i386_start_kernel+0x92/0x96 This happens in a corner case. If CGROUP_SCHED=y but CFS_BANDWIDTH=n && FAIR_GROUP_SCHED=n && RT_GROUP_SCHED=n, we have: cpu_files[] = { { } /* terminate */ } When we pass cpu_files to cgroup_apply_cftypes(), as cpu_files[0].ss is NULL, we'll access NULL pointer. The bug was introduced by commit de00ffa56ea3132c6013fc8f07133b8a1014cf53 ("cgroup: make cgroup_subsys->base_cftypes use cgroup_add_cftypes()"). Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | cgroup: deal with dummp_top in cgroup_name() and cgroup_path()Li Zefan2014-02-141-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My kernel fails to boot, because blkcg calls cgroup_path() while cgroupfs is not mounted. Fix both cgroup_name() and cgroup_path(). Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | cgroup: fix memory leak in cgroup_mount()Li Zefan2014-02-141-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We should free the memory allocated in parse_cgroupfs_options() before calling this function again. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | cgroup: fix locking in cgroupstats_build()Li Zefan2014-02-141-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | css_set_lock has been converted to css_set_rwsem, and rwsem can't nest inside rcu_read_lock. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | cgroup: fix coccinelle warningsFengguang Wu2014-02-131-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernel/cgroup.c:2256:1-3: WARNING: PTR_RET can be used Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR Generated by: coccinelle/api/ptr_ret.cocci Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | sparc: fix implicit include of slab.h in leon_pci_grpci2.cPaul Gortmaker2014-02-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To fix: arch/sparc/kernel/leon_pci_grpci2.c: In function 'grpci2_of_probe': arch/sparc/kernel/leon_pci_grpci2.c:720:2: error: implicit declaration of function 'kzalloc' [-Werror=implicit-function-declaration] arch/sparc/kernel/leon_pci_grpci2.c:720:20: error: assignment makes pointer from integer without a cast [-Werror] arch/sparc/kernel/leon_pci_grpci2.c:882:2: error: implicit declaration of function 'kfree' [-Werror=implicit-function-declaration] cc1: all warnings being treated as errors make[2]: *** [arch/sparc/kernel/leon_pci_grpci2.o] Error 1 According to Stephen, these types of failures are caused by commit 2bd59d48ebfb ("cgroup: convert to kernfs") which was being included implicitly via cgroup.h's inclusion of xattr.h (which has now been removed). Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
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