kernel/linux.git/drivers/base/core.c, branch v5.10.78

driver core: Reject pointless SYNC_STATE_ONLY device links

2021-10-20T09:45:01+00:00

commit f729a592adb6760013c3e48622a5bf256b992452 upstream. SYNC_STATE_ONLY device links intentionally allow cycles because cyclic sync_state() dependencies are valid and necessary. However a SYNC_STATE_ONLY device link where the consumer and the supplier are the same device is pointless because the device link would be deleted as soon as the device probes (because it's also the consumer) and won't affect when the sync_state() callback is called. It's a waste of CPU cycles and memory to create this device link. So reject any attempts to create such a device link. Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag") Cc: stable Reported-by: Ulf Hansson Reviewed-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20210929190549.860541-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman

PCI/MSI: Protect msi_desc::masked for multi-MSI

2021-08-18T06:59:17+00:00

commit 77e89afc25f30abd56e76a809ee2884d7c1b63ce upstream. Multi-MSI uses a single MSI descriptor and there is a single mask register when the device supports per vector masking. To avoid reading back the mask register the value is cached in the MSI descriptor and updates are done by clearing and setting bits in the cache and writing it to the device. But nothing protects msi_desc::masked and the mask register from being modified concurrently on two different CPUs for two different Linux interrupts which belong to the same multi-MSI descriptor. Add a lock to struct device and protect any operation on the mask and the mask register with it. This makes the update of msi_desc::masked unconditional, but there is no place which requires a modification of the hardware register without updating the masked cache. msi_mask_irq() is now an empty wrapper which will be cleaned up in follow up changes. The problem goes way back to the initial support of multi-MSI, but picking the commit which introduced the mask cache is a valid cut off point (2.6.30). Fixes: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code") Signed-off-by: Thomas Gleixner Tested-by: Marc Zyngier Reviewed-by: Marc Zyngier Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.726833414@linutronix.de Signed-off-by: Greg Kroah-Hartman

driver core: Prevent warning when removing a device link from unregistered consumer

2021-07-28T12:35:47+00:00

commit e64daad660a0c9ace3acdc57099fffe5ed83f977 upstream. sysfs_remove_link() causes a warning if the parent directory does not exist. That can happen if the device link consumer has not been registered. So do not attempt sysfs_remove_link() in that case. Fixes: 287905e68dd29 ("driver core: Expose device link details in sysfs") Signed-off-by: Adrian Hunter Cc: stable@vger.kernel.org # 5.9+ Reviewed-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20210716114408.17320-2-adrian.hunter@intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

drivers: base: Fix device link removal

2021-06-03T07:00:34+00:00

commit 80dd33cf72d1ab4f0af303f1fa242c6d6c8d328f upstream. When device_link_free() drops references to the supplier and consumer devices of the device link going away and the reference being dropped turns out to be the last one for any of those device objects, its ->release callback will be invoked and it may sleep which goes against the SRCU callback execution requirements. To address this issue, make the device link removal code carry out the device_link_free() actions preceded by SRCU synchronization from a separate work item (the "long" workqueue is used for that, because it does not matter when the device link memory is released and it may take time to get to that point) instead of using SRCU callbacks. While at it, make the code work analogously when SRCU is not enabled to reduce the differences between the SRCU and non-SRCU cases. Fixes: 843e600b8a2b ("driver core: Fix sleeping in invalid context during device link deletion") Cc: stable Reported-by: chenxiang (M) Tested-by: chenxiang (M) Reviewed-by: Saravana Kannan Signed-off-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/5722787.lOV4Wx5bFT@kreacher Signed-off-by: Greg Kroah-Hartman

driver core: Extend device_is_dependent()

2021-01-27T10:55:18+00:00

commit 3d1cf435e201d1fd63e4346b141881aed086effd upstream. If the device passed as the target (second argument) to device_is_dependent() is not completely registered (that is, it has been initialized, but not added yet), but the parent pointer of it is set, it may be missing from the list of the parent's children and device_for_each_child() called by device_is_dependent() cannot be relied on to catch that dependency. For this reason, modify device_is_dependent() to check the ancestors of the target device by following its parent pointer in addition to the device_for_each_child() walk. Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support") Reported-by: Stephan Gerhold Tested-by: Stephan Gerhold Reviewed-by: Saravana Kannan Signed-off-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/17705994.d592GUb2YH@kreacher Cc: stable Signed-off-by: Greg Kroah-Hartman

driver core: Fix device link device name collision

2021-01-27T10:55:18+00:00

commit e020ff611ba9be54e959e6b548038f8a020da1c9 upstream. The device link device's name was of the form: -- This can cause name collision as reported here [1] as device names are not globally unique. Since device names have to be unique within the bus/class, add the bus/class name as a prefix to the device names used to construct the device link device name. So the devuce link device's name will be of the form: :--: [1] - https://lore.kernel.org/lkml/20201229033440.32142-1-michael@walle.cc/ Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs") Cc: stable@vger.kernel.org Reported-by: Michael Walle Tested-by: Michael Walle Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20210110175408.1465657-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman

Revert "device property: Keep secondary firmware node secondary by type"

2021-01-12T19:18:24+00:00

commit 47f4469970d8861bc06d2d4d45ac8200ff07c693 upstream. While commit d5dcce0c414f ("device property: Keep secondary firmware node secondary by type") describes everything correct in its commit message, the change it made does the opposite and original commit c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()") was fully correct. Revert the former one here and improve documentation in the next patch. Fixes: d5dcce0c414f ("device property: Keep secondary firmware node secondary by type") Signed-off-by: Bard Liao Reviewed-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Cc: 5.10+ # 5.10+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

driver: core: Fix list corruption after device_del()

2020-12-30T10:54:26+00:00

commit 66482f640755b31cb94371ff6cef17400cda6db5 upstream. The device_links_purge() function (called from device_del()) tries to remove the links.needs_suppliers list entry, but it's using list_del(), hence it doesn't initialize after the removal. This is OK for normal cases where device_del() is called via device_destroy(). However, it's not guaranteed that the device object will be really deleted soon after device_del(). In a minor case like HD-audio codec reconfiguration that re-initializes the device after device_del(), it may lead to a crash by the corrupted list entry. As a simple fix, replace list_del() with list_del_init() in order to make the list intact after the device_del() call. Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition") Cc: Reviewed-by: Rafael J. Wysocki Signed-off-by: Takashi Iwai Link: https://lore.kernel.org/r/20201208190326.27531-1-tiwai@suse.de Cc: Saravana Kannan Signed-off-by: Greg Kroah-Hartman

PM: runtime: Drop runtime PM references to supplier on link removal

2020-11-02T17:14:07+00:00

While removing a device link, drop the supplier device's runtime PM usage counter as many times as needed to drop all of the runtime PM references to it from the consumer in addition to dropping the consumer's link count. Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links") Signed-off-by: Rafael J. Wysocki Cc: 5.1+ # 5.1+ Tested-by: Xiang Chen Reviewed-by: Greg Kroah-Hartman

device property: Don't clear secondary pointer for shared primary firmware node

2020-10-27T18:20:03+00:00

It appears that firmware nodes can be shared between devices. In such case when a (child) device is about to be deleted, its firmware node may be shared and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link of the shared primary firmware node. In order to prevent that, check, if the device has a parent and parent's firmware node is shared with its child, and avoid crashing the link. Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()") Reported-by: Ferry Toth Signed-off-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Tested-by: Ferry Toth Cc: 5.9+ # 5.9+ Signed-off-by: Rafael J. Wysocki