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authorDan Williams <dan.j.williams@intel.com>2019-07-18 03:08:26 +0200
committerDan Williams <dan.j.williams@intel.com>2019-07-19 01:23:27 +0200
commit87a30e1f05d73a34e6d1895065541369131aaf1c (patch)
treea5582d3cd7723db8b7ad2f4801a5540c36c5266a /drivers/base
parentlibnvdimm/bus: Fix wait_nvdimm_bus_probe_idle() ABBA deadlock (diff)
downloadlinux-87a30e1f05d73a34e6d1895065541369131aaf1c.tar.xz
linux-87a30e1f05d73a34e6d1895065541369131aaf1c.zip
driver-core, libnvdimm: Let device subsystems add local lockdep coverage
For good reason, the standard device_lock() is marked lockdep_set_novalidate_class() because there is simply no sane way to describe the myriad ways the device_lock() ordered with other locks. However, that leaves subsystems that know their own local device_lock() ordering rules to find lock ordering mistakes manually. Instead, introduce an optional / additional lockdep-enabled lock that a subsystem can acquire in all the same paths that the device_lock() is acquired. A conversion of the NFIT driver and NVDIMM subsystem to a lockdep-validate device_lock() scheme is included. The debug_nvdimm_lock() implementation implements the correct lock-class and stacking order for the libnvdimm device topology hierarchy. Yes, this is a hack, but hopefully it is a useful hack for other subsystems device_lock() debug sessions. Quoting Greg: "Yeah, it feels a bit hacky but it's really up to a subsystem to mess up using it as much as anything else, so user beware :) I don't object to it if it makes things easier for you to debug." Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/core.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c
index eaf3aa0cb803..4825949d6547 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1663,6 +1663,9 @@ void device_initialize(struct device *dev)
kobject_init(&dev->kobj, &device_ktype);
INIT_LIST_HEAD(&dev->dma_pools);
mutex_init(&dev->mutex);
+#ifdef CONFIG_PROVE_LOCKING
+ mutex_init(&dev->lockdep_mutex);
+#endif
lockdep_set_novalidate_class(&dev->mutex);
spin_lock_init(&dev->devres_lock);
INIT_LIST_HEAD(&dev->devres_head);