linux/drivers/base/core.c, branch v3.14-rc4

Revert "kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers"

2014-01-13T22:05:13Z

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 Cc: Alan Stern Cc: kbuild test robot Signed-off-by: Greg Kroah-Hartman

Revert "sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()"

2014-01-13T21:51:36Z

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 Signed-off-by: Greg Kroah-Hartman

sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()

2014-01-11T00:03:19Z

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 Signed-off-by: Greg Kroah-Hartman

kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers

2014-01-10T22:01:05Z

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 Cc: Alan Stern Cc: kbuild test robot Signed-off-by: Greg Kroah-Hartman

Driver core: Fix device_add_attrs() error code path

2013-12-18T23:50:16Z

If the addition of dev_attr_online fails, device_add_attrs() should remove device attribute groups as well as type and class attribute groups before returning an error code. Make that happen. Signed-off-by: Rafael J. Wysocki Acked-by: Toshi Kani Signed-off-by: Greg Kroah-Hartman

driver core: fix device_create() error path

2013-12-09T02:25:10Z

We call put_device() in the error path, which is fine for dev==NULL. However, in case kobject_set_name_vargs() fails, we have dev!=NULL but device_initialized() wasn't called, yet. Fix this by splitting device_register() into explicit calls to device_add() and an early call to device_initialize(). Signed-off-by: David Herrmann Signed-off-by: Greg Kroah-Hartman

drivers/base/core.c: output device renaming messages with dev_dbg().

2013-10-17T01:33:27Z

Replace pr_debug() with dev_dbg(). Signed-off-by: ethan.zhao Signed-off-by: Greg Kroah-Hartman

driver core: remove dev_bin_attrs from struct class

2013-10-06T07:01:47Z

No in-kernel code is now using this, they have all be converted over to using the bin_attrs support in attribute groups, so this field, and the code in the driver core that was creating/remove the binary files can be removed. Signed-off-by: Greg Kroah-Hartman

driver core: remove dev_attrs from struct class

2013-10-06T06:59:34Z

Now that all in-kernel users of the dev_attrs field are converted to use dev_groups, we can safely remove dev_attrs from struct class. Signed-off-by: Greg Kroah-Hartman

Merge 3.12-rc3 into driver-core-next

2013-09-30T01:29:23Z

We want the driver core and sysfs fixes in here to make merges and development easier. Signed-off-by: Greg Kroah-Hartman