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| author | Alexander Duyck <alexander.h.duyck@linux.intel.com> | 2019-01-22 10:39:10 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-31 14:20:53 +0100 |
| commit | 3451a495ef244a88ed6317a035299d835554d579 (patch) | |
| tree | e35d679a4caec70f62f0c6bd6e638162ffc25d05 /drivers/base/core.c | |
| parent | 0fe6f7874d467456da6f6a221dd92499a3ab1780 (diff) | |
| download | lwn-3451a495ef244a88ed6317a035299d835554d579.tar.gz lwn-3451a495ef244a88ed6317a035299d835554d579.zip | |
driver core: Establish order of operations for device_add and device_del via bitflag
Add an additional bit flag to the device_private struct named "dead".
This additional flag provides a guarantee that when a device_del is
executed on a given interface an async worker will not attempt to attach
the driver following the earlier device_del call. Previously this
guarantee was not present and could result in the device_del call
attempting to remove a driver from an interface only to have the async
worker attempt to probe the driver later when it finally completes the
asynchronous probe call.
One additional change added was that I pulled the check for dev->driver
out of the __device_attach_driver call and instead placed it in the
__device_attach_async_helper call. This was motivated by the fact that the
only other caller of this, __device_attach, had already taken the
device_lock() and checked for dev->driver. Instead of testing for this
twice in this path it makes more sense to just consolidate the dev->dead
and dev->driver checks together into one set of checks.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/core.c')
| -rw-r--r-- | drivers/base/core.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 26f8cd6dd0b3..1febfd2a353a 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2080,6 +2080,17 @@ 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; + device_unlock(dev); + /* Notify clients of device removal. This call must come * before dpm_sysfs_remove(). */ |