linux/drivers/base/core.c, branch v4.11

drivers core: remove assert_held_device_hotplug()

2017-03-16T23:56:19Z

The last caller of assert_held_device_hotplug() is gone, so remove it again. Link: http://lkml.kernel.org/r/20170314125226.16779-3-heiko.carstens@de.ibm.com Signed-off-by: Heiko Carstens Acked-by: Dan Williams Cc: Michal Hocko Cc: "Rafael J. Wysocki" Cc: Vladimir Davydov Cc: Ben Hutchings Cc: Gerald Schaefer Cc: Martin Schwidefsky Cc: Sebastian Ott Cc: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sched/headers: Prepare to move signal wakeup & sigpending methods from into

2017-03-02T07:42:32Z

Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

mm: validate device_hotplug is held for memory hotplug

2017-02-25T01:46:53Z

mem_hotplug_begin() assumes that it can set mem_hotplug.active_writer and run the hotplug process without racing another thread. Validate this assumption with a lockdep assertion. Link: http://lkml.kernel.org/r/148693886229.16345.1770484669403334689.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Reported-by: Ben Hutchings Cc: Michal Hocko Cc: Toshi Kani Cc: Vlastimil Babka Cc: Logan Gunthorpe Cc: Greg Kroah-Hartman Cc: Masayoshi Mizuma Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Revert "driver core: Add deferred_probe attribute to devices in sysfs"

2017-01-14T13:09:03Z

This reverts commit 6751667a29d6fd64afb9ce30567ad616b68ed789. Rob Herring objected to it, and a replacement for it will be added using debugfs in the future. Cc: Ben Hutchings Reported-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

driver core: Silence device links sphinx warning

2016-12-05T14:02:20Z

Silence this warning emitted by sphinx: include/linux/device.h:938: warning: No description found for parameter 'links' While at it, fix typos in comments of device links code. Cc: Rafael J. Wysocki Cc: Jonathan Corbet Cc: Silvio Fricke Signed-off-by: Lukas Wunner Reviewed-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman

driver core: Add deferred_probe attribute to devices in sysfs

2016-11-10T16:22:23Z

It is sometimes useful to know that a device is on the deferred probe list rather than, say, not having a driver available. Expose this information to user-space. Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

PM / runtime: Optimize the use of device links

2016-10-31T17:42:51Z

If the device has no links to suppliers that should be used for runtime PM (links with DEVICE_LINK_PM_RUNTIME set), there is no reason to walk the list of suppliers for that device during runtime suspend and resume. Add a simple mechanism to detect that case and possibly avoid the extra unnecessary overhead. Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PM / runtime: Use device links

2016-10-31T17:42:51Z

Modify the runtime PM framework to use device links to ensure that supplier devices will not be suspended if any of their consumer devices are active. The idea is to reference count suppliers on the consumer's resume and drop references to them on its suspend. The information on whether or not the supplier has been reference counted by the consumer's (runtime) resume is stored in a new field (rpm_active) in the link object for each link. It may be necessary to clean up those references when the supplier is unbinding and that's why the links whose status is DEVICE_LINK_SUPPLIER_UNBIND are skipped by the runtime suspend and resume code. The above means that if the consumer device is probed in the runtime-active state, the supplier has to be resumed and reference counted by device_link_add() so the code works as expected on its (runtime) suspend. There is a new flag, DEVICE_LINK_RPM_ACTIVE, to tell device_link_add() about that (in which case the caller is responsible for making sure that the consumer really will be runtime-active when runtime PM is enabled for it). The other new link flag, DEVICE_LINK_PM_RUNTIME, tells the core whether or not the link should be used for runtime PM at all. Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

driver core: Functional dependencies tracking support

2016-10-31T17:36:20Z

Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2016-10-04T03:03:24Z

Pull driver core updates from Greg KH: "Here are the "big" driver core patches for 4.9-rc1. Also in here are a number of debugfs fixes that cropped up due to the changes that happened in 4.8 for that filesystem. Overall, nothing major, just a few fixes and cleanups. All of these have been in linux-next with no reported issues" * tag 'driver-core-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (23 commits) drivers: dma-coherent: Move spinlock in dma_alloc_from_coherent() drivers: dma-coherent: Fix DMA coherent size for less than page MAINTAINERS: extend firmware_class maintainer list debugfs: propagate release() call result driver-core: platform: Catch errors from calls to irq_get_irq_data sysfs print name of undiscoverable attribute group carl9170: fix debugfs crashes b43legacy: fix debugfs crash b43: fix debugfs crash debugfs: introduce a public file_operations accessor device core: Remove deprecated create_singlethread_workqueue drivers/base dmam_declare_coherent_memory leaks platform: don't return 0 from platform_get_irq[_byname]() on error cpu: clean up register_cpu func dma-mapping: use vma_pages(). drivers: dma-coherent: use vma_pages(). attribute_container: Fix typo base: soc: make it explicitly non-modular drivers: base: dma-mapping: page align the size when unmap_kernel_range platform driver: fix use-after-free in platform_device_del() ...