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* Revert "kernfs: fix get_active failure handling in kernfs_seq_*()"Greg Kroah-Hartman2014-01-131-44/+7Star
| | | | | | | | | | | | | | | This reverts commit d92d2e6bd72b653f9811e0c9c46307c743b3fc58. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: replace kernfs_node->u.completion with ↵Greg Kroah-Hartman2014-01-132-13/+18
| | | | | | | | | | | | | | | | | kernfs_root->deactivate_waitq" This reverts commit ea1c472dfeada211a0100daa7976e8e8e779b858. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()"Greg Kroah-Hartman2014-01-132-20/+12Star
| | | | | | | | | | | | | | | This reverts commit a69d001cfc712b96ec9d7ba44d6285702a38dabf. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: remove KERNFS_REMOVED"Greg Kroah-Hartman2014-01-135-60/+43Star
| | | | | | | | | | | | | | | This reverts commit ae34372eb8408b3d07e870f1939f99007a730d28. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: restructure removal path to fix possible premature return"Greg Kroah-Hartman2014-01-132-87/+53Star
| | | | | | | | | | | | | | | This reverts commit 45a140e587f3d32d8d424ed940dffb61e1739047. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()"Greg Kroah-Hartman2014-01-133-35/+14Star
| | | | | | | | | | | | | | | This reverts commit f601f9a2bf7dc1f7ee18feece4c4e2fc6845d6c4. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: remove kernfs_addrm_cxt"Greg Kroah-Hartman2014-01-135-29/+121
| | | | | | | | | | | | | | | This reverts commit 99177a34110889a8f2c36420c34e3bcc9bfd8a70. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: make kernfs_get_active() block if the node is deactivated ↵Greg Kroah-Hartman2014-01-131-21/+4Star
| | | | | | | | | | | | | | | | | but not removed" This reverts commit 895a068a524e134900b9d98b519309b7aae7bbb1. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: implement kernfs_{de|re}activate[_self]()"Greg Kroah-Hartman2014-01-132-123/+2Star
| | | | | | | | | | | | | | | This reverts commit 9f010c2ad5194a4b682e747984477850fabd03be. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs, sysfs, driver-core: implement kernfs_remove_self() and its ↵Greg Kroah-Hartman2014-01-136-127/+0Star
| | | | | | | | | | | | | | | | | | | wrappers" This reverts commit 1ae06819c77cff1ea2833c94f8c093fe8a5c79db. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: 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>
* Revert "pci: use device_remove_file_self() instead of ↵Greg Kroah-Hartman2014-01-131-6/+18
| | | | | | | | | | | | | | | | | | | device_schedule_callback()" This reverts commit 6716d289c437ad42dee455d241b29b71a816fbff. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: 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>
* Revert "scsi: use device_remove_file_self() instead of ↵Greg Kroah-Hartman2014-01-131-2/+13
| | | | | | | | | | | | | | | | | | | device_schedule_callback()" This reverts commit de1dee7820c44b1a5765265ed7ca8ee44f2367c1. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: 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>
* Revert "s390: use device_remove_file_self() instead of ↵Greg Kroah-Hartman2014-01-134-32/+27Star
| | | | | | | | | | | | | | | | | | | | | device_schedule_callback()" This reverts commit bdbb0a1376635d80e096f6433595a38984cf5408. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: 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>
* Revert "sysfs, driver-core: remove unused ↵Greg Kroah-Hartman2014-01-134-1/+144
| | | | | | | | | | | | | | | | | {sysfs|device}_schedule_callback_owner()" This reverts commit d1ba277e79889085a2faec3b68b91ce89c63f888. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs: remove unnecessary NULL check in __kernfs_remove()"Greg Kroah-Hartman2014-01-131-0/+3
| | | | | | | | | | | | | | | This reverts commit 88533f990c616cf50c2fe585ea03f75c806a293d. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: remove unnecessary NULL check in __kernfs_remove()Tejun Heo2014-01-121-3/+0Star
| | | | | | | | | | | | | | | | | | | | | 895a068a524e ("kernfs: make kernfs_get_active() block if the node is deactivated but not removed") added "struct kernfs_root *root = kernfs_root(kn);" at the head of the function; however, the parameter @kn is checked for later implying that the function may be called with NULL. This means that we may end up invoking kernfs_root() with NULL which will oops. None of the existing users invokes removal with NULL @kn, so this bug doesn't actually trigger. We can relocate kernfs_root() invocation after NULL check; however, allowing NULL param tends to cause more confusion than actually helping anything. As there's no existing user, let's remove the spurious NULL check. This bug was detected by smatch. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* drivers/base: provide an infrastructure for componentised subsystemsRussell King2014-01-113-1/+415
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Subsystems such as ALSA, DRM and others require a single card-level device structure to represent a subsystem. However, firmware tends to describe the individual devices and the connections between them. Therefore, we need a way to gather up the individual component devices together, and indicate when we have all the component devices. We do this in DT by providing a "superdevice" node which specifies the components, eg: imx-drm { compatible = "fsl,drm"; crtcs = <&ipu1>; connectors = <&hdmi>; }; The superdevice is declared into the component support, along with the subcomponents. The superdevice receives callbacks to locate the subcomponents, and identify when all components are present. At this point, we bind the superdevice, which causes the appropriate subsystem to be initialised in the conventional way. When any of the components or superdevice are removed from the system, we unbind the superdevice, thereby taking the subsystem down. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()Tejun Heo2014-01-114-144/+1Star
| | | | | | | | | 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>
* s390: use device_remove_file_self() instead of device_schedule_callback()Tejun Heo2014-01-104-27/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* scsi: use device_remove_file_self() instead of device_schedule_callback()Tejun Heo2014-01-101-13/+2Star
| | | | | | | | | | | | 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>
* pci: use device_remove_file_self() instead of device_schedule_callback()Tejun Heo2014-01-101-18/+6Star
| | | | | | | | | | | | 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>
* kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappersTejun Heo2014-01-106-0/+127
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 and deactivates using __kernfs_deactivate_self(), removes the self node, and restores active ref to the dead node using __kernfs_reactivate_self() 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. 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: Updated to use __kernfs_{de|re}activate_self(). 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>
* kernfs: implement kernfs_{de|re}activate[_self]()Tejun Heo2014-01-102-2/+123
| | | | | | | | | | | | | | | | | | | | | This patch implements four functions to manipulate deactivation state - deactivate, reactivate and the _self suffixed pair. A new fields kernfs_node->deact_depth is added so that concurrent and nested deactivations are handled properly. kernfs_node->hash is moved so that it's paired with the new field so that it doesn't increase the size of kernfs_node. A kernfs user's lock would normally nest inside active ref but during removal the user may want to perform kernfs_remove() while holding the said lock, which would introduce a reverse locking dependency. This function can be used to break such reverse dependency by allowing deactivation step to performed separately outside user's critical section. This will also be used implement kernfs_remove_self(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: make kernfs_get_active() block if the node is deactivated but not ↵Tejun Heo2014-01-101-4/+21
| | | | | | | | | | | | | | | | | | removed Currently, kernfs_get_active() fails if the target node is deactivated. This is fine as a node always gets removed after deactivation; however, we're gonna add reactivation so the assumption won't hold. It'd be incorrect for kernfs_get_active() to fail for a node which was deactivated only temporarily. This patch makes kernfs_get_active() block if the node is deactivated but not removed. If the node gets reactivated (not yet implemented), it will be retried and succeed. If the node gets removed, it will be woken up and fail. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: remove kernfs_addrm_cxtTejun Heo2014-01-105-121/+29Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 the parent's active ref and kernfs_mutex itself. kernfs_get/put_active() and kernfs_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: Updated to fit the v2 restructuring of removal path. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()Tejun Heo2014-01-103-14/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 fixed by moving kernfs_unmap_bin_file() invocation from kernfs_addrm_finish() to __kernfs_remove(). The function may be called multiple times but that shouldn't do any harm. We end up dropping kernfs_mutex in the removal loop and the node may be removed inbetween by someone else. kernfs_unlink_sibling() is updated to test whether the node has already been removed and return accordingly. __kernfs_remove() in turn performs post-unlinking cleanup only if it actually unlinked the node. KERNFS_HAS_MMAP test is moved out of the unmap function into __kernfs_remove() so that we don't unlock kernfs_mutex unnecessarily. While at it, drop the now meaningless "bin" qualifier from the function name. v2: Rewritten to fit the v2 restructuring of removal path. HAS_MMAP test relocated. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: restructure removal path to fix possible premature returnTejun Heo2014-01-102-53/+87
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 deactivates the subtree, drains it and then unlinks 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. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: remove KERNFS_REMOVEDTejun Heo2014-01-105-43/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 those of deactivation and removal from rbtree. 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. KERNFS_REMOVED is also used to decide whether a node is still visible to vfs layer, which is rather redundant as equivalent determination can be made by testing whether the node is on its parent's children rbtree or not. 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.. * KERNFS_REMOVED tests in add and rename paths are replaced with kernfs_get/put_active() of the target nodes. Due to the way the add path is structured now, active ref handling is done in the callers of kernfs_add_one(). This will be consolidated up later. * kernfs_remove_one() is updated to deactivate instead of setting KERNFS_REMOVED. This removes deactivation from kernfs_deactivate(), which is now renamed to kernfs_drain(). * kernfs_dop_revalidate() now tests RB_EMPTY_NODE(&kn->rb) instead of KERNFS_REMOVED and KERNFS_REMOVED test in kernfs_dir_pos() is dropped. A node which is removed from the children rbtree is not included in the iteration in the first place. This means that a node may be visible through vfs a bit longer - it's now also visible after deactivation until the actual removal. This slightly enlarged window difference doesn't make any difference to the userland. * 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. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()Tejun Heo2014-01-102-12/+20
| | | | | | | | | | | | | | | | | | | 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 and use KERNFS_LOCKDEP in kernfs_deactivate() too. 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. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: replace kernfs_node->u.completion with kernfs_root->deactivate_waitqTejun Heo2014-01-102-18/+13Star
| | | | | | | | | | | | | | | | | | | 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. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: fix get_active failure handling in kernfs_seq_*()Tejun Heo2014-01-101-7/+44
| | | | | | | | | | | | | | | | | | | | | | | | | When kernfs_seq_start() fails to obtain an active reference, it returns ERR_PTR(-ENODEV). kernfs_seq_stop() is then invoked with the error pointer value; however, it still proceeds to invoke kernfs_put_active() on the node leading to unbalanced put. If kernfs_seq_stop() is called even after active ref failure, it should skip invocation of @ops->seq_stop() and put_active. Unfortunately, this is a bit complicated because active ref failure isn't the only thing which may fail with ERR_PTR(-ENODEV). @ops->seq_start/next() may also fail with the error value and kernfs_seq_stop() doesn't have a way to tell apart those failures. Work it around by factoring out the active part of kernfs_seq_stop() into kernfs_seq_stop_active() and invoking it directly if @ops->seq_start/next() fail with ERR_PTR(-ENODEV) and updating kernfs_seq_stop() to skip kernfs_seq_stop_active() on ERR_PTR(-ENODEV). This is a bit nasty but ensures that the active put is skipped iff get_active failed in kernfs_seq_start(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* firmware_class: Fix the file size checkBen Hutchings2014-01-091-3/+3
| | | | | | | | | We expect to read firmware blobs with a single call to kernel_read(), which returns int. Therefore the size must be within the range of int, not long. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* driver-core: Fix use-after-free triggered by bus_unregister()Bart Van Assche2014-01-091-2/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid that bus_unregister() triggers a use-after-free with CONFIG_DEBUG_KOBJECT_RELEASE=y. This patch avoids that the following sequence triggers a kernel crash with memory poisoning enabled: * bus_register() * driver_register() * driver_unregister() * bus_unregister() The above sequence causes the bus private data to be freed from inside the bus_unregister() call although it is not guaranteed in that function that the reference count on the bus private data has dropped to zero. As an example, with CONFIG_DEBUG_KOBJECT_RELEASE=y the ${bus}/drivers kobject is still holding a reference on bus->p->subsys.kobj via its parent pointer at the time the bus private data is freed. Fix this by deferring freeing the bus private data until the last kobject_put() call on bus->p->subsys.kobj. The kernel oops triggered by the above sequence and with memory poisoning enabled and that is fixed by this patch is as follows: general protection fault: 0000 [#1] PREEMPT SMP CPU: 3 PID: 2711 Comm: kworker/3:32 Tainted: G W O 3.13.0-rc4-debug+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: events kobject_delayed_cleanup task: ffff880037f866d0 ti: ffff88003b638000 task.ti: ffff88003b638000 Call Trace: [<ffffffff81263105>] ? kobject_get_path+0x25/0x100 [<ffffffff81264354>] kobject_uevent_env+0x134/0x600 [<ffffffff8126482b>] kobject_uevent+0xb/0x10 [<ffffffff81262fa2>] kobject_delayed_cleanup+0xc2/0x1b0 [<ffffffff8106c047>] process_one_work+0x217/0x700 [<ffffffff8106bfdb>] ? process_one_work+0x1ab/0x700 [<ffffffff8106c64b>] worker_thread+0x11b/0x3a0 [<ffffffff8106c530>] ? process_one_work+0x700/0x700 [<ffffffff81074b70>] kthread+0xf0/0x110 [<ffffffff81074a80>] ? insert_kthread_work+0x80/0x80 [<ffffffff815673bc>] ret_from_fork+0x7c/0xb0 [<ffffffff81074a80>] ? insert_kthread_work+0x80/0x80 Code: 89 f8 48 89 e5 f6 82 c0 27 63 81 20 74 15 0f 1f 44 00 00 48 83 c0 01 0f b6 10 f6 82 c0 27 63 81 20 75 f0 5d c3 66 0f 1f 44 00 00 <80> 3f 00 55 48 89 e5 74 15 48 89 f8 0f 1f 40 00 48 83 c0 01 80 RIP [<ffffffff81267ed0>] strlen+0x0/0x30 RSP <ffff88003b639c70> ---[ end trace 210f883ef80376aa ]--- Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* firmware loader: Add sparse annotationBart Van Assche2014-01-091-0/+1
| | | | | | | | | | Avoid that sparse reports the following warning on __fw_free_buf(): drivers/base/firmware_class.c:230:9: warning: context imbalance in '__fw_free_buf' - unexpected unlock Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kobject: Fix source code comment spellingBart Van Assche2014-01-091-1/+1
| | | | | Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kobject: introduce kobj_completion"Greg Kroah-Hartman2014-01-052-68/+0Star
| | | | | | | | | | | | | | This reverts commit eee031649707db3c9920d9498f8d03819b74fc23. Jeff writes: I have no objections to reverting it. There were concerns from Al Viro that it'd be tough to get right by callers and I had assumed it got dropped after that. I had planned on using it in my btrfs sysfs exports patchset but came up with a better way. Cc: Jeff Mahoney <jeffm@suse.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge 3.13-rc5 into staging-nextGreg Kroah-Hartman2013-12-24746-3809/+7275
|\ | | | | | | | | | | We want these fixes here to handle some merge issues. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * Linux 3.13-rc5Linus Torvalds2013-12-221-1/+1
| |
| * Merge tag 'fixes-for-linus' of ↵Linus Torvalds2013-12-226-26/+61
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC fixes from Olof Johansson: "Much smaller batch of fixes this week. Biggest one is a revert of an OMAP display change that removed some non-DT pinmux code that was still needed for 3.13 to get DSI displays to work. There's also a fix that resolves some misdescribed GPIO controller resources on shmobile. The rest are mostly smaller fixes, a couple of MAINTAINERS updates, etc" * tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: Revert "ARM: OMAP2+: Remove legacy mux code for display.c" MAINTAINERS: Add keystone clock drivers MAINTAINERS: Add keystone git tree information ARM: s3c64xx: dt: Fix boot failure due to double clock initialization ARM: shmobile: r8a7790: Fix GPIO resources in DTS irqchip: renesas-intc-irqpin: Fix register bitfield shift calculation ARM: shmobile: lager: phy fixup needs CONFIG_PHYLIB
| | * Merge tag 'renesas-fixes-for-v3.13' of ↵Kevin Hilman2013-12-203-16/+20
| | |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas into fixes From Simon Horman: Renesas ARM based SoC fixes for v3.13 * r8a7790 (R-Car H1) SoC - Correct GPIO resources in DT. This problem has been present since GPIOs were added to the r8a7790 SoC by f98e10c88aa95bf7 ("ARM: shmobile: r8a7790: Add GPIO controller devices to device tree") in v3.12-rc1. * irqchip renesas-intc-irqpin - Correct register bitfield shift calculation This bug has been present since the renesas-intc-irqpin driver was introduced by 443580486e3b9657 ("irqchip: Renesas INTC External IRQ pin driver") in v3.10-rc1 * Lager board - Do not build the phy fixup unless CONFIG_PHYLIB is enabled This problem was introduced by 48c8b96f21817aad * tag 'renesas-fixes-for-v3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas: ARM: shmobile: r8a7790: Fix GPIO resources in DTS irqchip: renesas-intc-irqpin: Fix register bitfield shift calculation ARM: shmobile: lager: phy fixup needs CONFIG_PHYLIB Signed-off-by: Kevin Hilman <khilman@linaro.org>
| | | * ARM: shmobile: r8a7790: Fix GPIO resources in DTSMagnus Damm2013-11-281-12/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The r8a7790 GPIO resources are currently incorrect. Fix that by making them match the English r8a7790 v0.6 data sheet. Tested with GPIO LED using Lager DT reference. This problem has been present since GPIOs were added to the r8a7790 SoC by f98e10c88aa95bf7 ("ARM: shmobile: r8a7790: Add GPIO controller devices to device tree") in v3.12-rc1. Signed-off-by: Magnus Damm <damm@opensource.se> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
| | | * irqchip: renesas-intc-irqpin: Fix register bitfield shift calculationLaurent Pinchart2013-11-241-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The SENSE register bitfield position is incorrectly computed for SoCs that use 2-bit IRQ sense fields. Fix it. This has been tested on the Marzen (H1) and Bockw (M1) boards. This bug has been present since the renesas-intc-irqpin driver was introduced by 443580486e3b9657 ("irqchip: Renesas INTC External IRQ pin driver") in v3.10-rc1. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Magnus Damm <damm@opensource.se> Tested-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
| | | * ARM: shmobile: lager: phy fixup needs CONFIG_PHYLIBSimon Horman2013-11-241-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Do not build the phy fixup unless CONFIG_PHYLIB is enabled. Other than not being useful it is also not possible to link the code under this condition as phy_register_fixup_for_id(), mdiobus_read() and mdiobus_write() are absent. arch/arm/mach-shmobile/built-in.o: In function `lager_ksz8041_fixup': board-lager.c:(.text+0xb8): undefined reference to `mdiobus_read' board-lager.c:(.text+0xd4): undefined reference to `mdiobus_write' arch/arm/mach-shmobile/built-in.o: In function `lager_init': board-lager.c:(.init.text+0xafc): undefined reference to `phy_register_fixup_for_id' This problem was introduced by 48c8b96f21817aad ("ARM: shmobile: Lager: add Micrel KSZ8041 PHY fixup") Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
| | * | Merge tag 'omap-for-v3.13/display-fix' of ↵Kevin Hilman2013-12-20522-2558/+4836
| | |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes I accidentally removed some mux code for omap4 that I thought was dead code as omap4 has been booting with device tree only since v3.10. Turns out I also removed some display related mux code, so let's revert that except for the dead code parts. * tag 'omap-for-v3.13/display-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap: (439 commits) Revert "ARM: OMAP2+: Remove legacy mux code for display.c" +Linux 3.13-rc4
| | | * | Revert "ARM: OMAP2+: Remove legacy mux code for display.c"Tomi Valkeinen2013-12-181-0/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit e30b06f4d5f000c31a7747a7e7ada78a5fd419a1 (ARM: OMAP2+: Remove legacy mux code for display.c) removed non-DT DSI and HDMI pinmuxing. However, DSI pinmuxing is still needed, and removing that caused DSI displays not to work. This reverts the DSI parts of the commit. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
| | * | | Merge tag 'keystone/maintainer-file' of ↵Kevin Hilman2013-12-201-0/+2
| | |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux-keystone into fixes From Santosh Shilimkar: Couple of updates to MAINTAINERS file for Keystone - Add git tree information - Add clock drivers entry * tag 'keystone/maintainer-file' of git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux-keystone: MAINTAINERS: Add keystone clock drivers MAINTAINERS: Add keystone git tree information Signed-off-by: Kevin Hilman <khilman@linaro.org>
| | | * | | MAINTAINERS: Add keystone clock driversSantosh Shilimkar2013-12-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cc: Mike Turquette <mturquette@linaro.org> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
| | | * | | MAINTAINERS: Add keystone git tree informationSantosh Shilimkar2013-12-161-0/+1
| | | | |/ | | | |/| | | | | | | | | | | | | | | | | | | | | Update the Keystone entry to add git tree information. Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
| | * | | ARM: s3c64xx: dt: Fix boot failure due to double clock initializationTomasz Figa2013-12-141-10/+1Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 4178bac ARM: call of_clk_init from default time_init handler added implicit call to of_clk_init() from default time_init callback, but it did not change platforms calling it from other callbacks, despite of not having custom time_init callbacks. This caused double clock initialization on such platforms, leading to boot failures. An example of such platform is mach-s3c64xx. This patch fixes boot failure on s3c64xx by dropping custom init_irq callback, which had a call to of_clk_init() and moving system reset initialization to init_machine callback. This allows us to have clocks initialized properly without a need to have custom init_time or init_irq callbacks. Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com> Signed-off-by: Olof Johansson <olof@lixom.net>
| * | | | Merge tag 'firewire-fix' of ↵Linus Torvalds2013-12-221-1/+0Star
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394 Pull firewire fixlet from Stefan Richter: "A one-liner to reenable WRITE SAME over SBP-2 like in v3.8...v3.12. Buggy targets which could malfunction when being subjected to this command are already sufficiently protected by a scsi_level check in sd + SCSI core" * tag 'firewire-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394: firewire: sbp2: bring back WRITE SAME support
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