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authorDan Williams <dan.j.williams@intel.com>2019-07-18 04:07:53 +0300
committerDan Williams <dan.j.williams@intel.com>2019-07-19 02:21:01 +0300
commit00289cd87676e14913d2d8492d1ce05c4baafdae (patch)
treeb4ab4a8ab2c3c582e8cb8afffc2061287d794555 /drivers/base
parentd1fdb6d8f6a4109a4263176c84b899076a5f8008 (diff)
downloadlinux-00289cd87676e14913d2d8492d1ce05c4baafdae.tar.xz
drivers/base: Introduce kill_device()
The libnvdimm subsystem arranges for devices to be destroyed as a result of a sysfs operation. Since device_unregister() cannot be called from an actively running sysfs attribute of the same device libnvdimm arranges for device_unregister() to be performed in an out-of-line async context. The driver core maintains a 'dead' state for coordinating its own racing async registration / de-registration requests. Rather than add local 'dead' state tracking infrastructure to libnvdimm device objects, export the existing state tracking via a new kill_device() helper. The kill_device() helper simply marks the device as dead, i.e. that it is on its way to device_del(), or returns that the device was already dead. This can be used in advance of calling device_unregister() for subsystems like libnvdimm that might need to handle multiple user threads racing to delete a device. This refactoring does not change any behavior, but it is a pre-requisite for follow-on fixes and therefore marked for -stable. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver...") Cc: <stable@vger.kernel.org> Tested-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/156341207332.292348.14959761496009347574.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/core.c27
1 files changed, 19 insertions, 8 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c
index fd7511e04e62..eaf3aa0cb803 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2211,6 +2211,24 @@ void put_device(struct device *dev)
}
EXPORT_SYMBOL_GPL(put_device);
+bool kill_device(struct device *dev)
+{
+ /*
+ * Require the device lock and set the "dead" flag to guarantee that
+ * the update behavior is consistent with the other bitfields near
+ * it and that we cannot have an asynchronous probe routine trying
+ * to run while we are tearing out the bus/class/sysfs from
+ * underneath the device.
+ */
+ lockdep_assert_held(&dev->mutex);
+
+ if (dev->p->dead)
+ return false;
+ dev->p->dead = true;
+ return true;
+}
+EXPORT_SYMBOL_GPL(kill_device);
+
/**
* device_del - delete device from system.
* @dev: device.
@@ -2230,15 +2248,8 @@ void device_del(struct device *dev)
struct kobject *glue_dir = NULL;
struct class_interface *class_intf;
- /*
- * Hold the device lock and set the "dead" flag to guarantee that
- * the update behavior is consistent with the other bitfields near
- * it and that we cannot have an asynchronous probe routine trying
- * to run while we are tearing out the bus/class/sysfs from
- * underneath the device.
- */
device_lock(dev);
- dev->p->dead = true;
+ kill_device(dev);
device_unlock(dev);
/* Notify clients of device removal. This call must come