From: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
commit 3451a495ef244a88ed6317a035299d835554d579 upstream.
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@xxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/base/base.h | 4 ++++
drivers/base/core.c | 11 +++++++++++
drivers/base/dd.c | 22 +++++++++++-----------
3 files changed, 26 insertions(+), 11 deletions(-)
diff --git a/drivers/base/base.h b/drivers/base/base.h
index 7a419a7a6235..559b047de9f7 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -66,6 +66,9 @@ struct driver_private {
* probed first.
* @device - pointer back to the struct device that this structure is
* associated with.
+ * @dead - This device is currently either in the process of or has been
+ * removed from the system. Any asynchronous events scheduled for this
+ * device should exit without taking any action.
*
* Nothing outside of the driver core should ever touch these fields.
*/
@@ -76,6 +79,7 @@ struct device_private {
struct klist_node knode_bus;
struct list_head deferred_probe;
struct device *device;
+ u8 dead:1;
};
#define to_device_private_parent(obj) \
container_of(obj, struct device_private, knode_parent)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 92e2c32c2227..37a90d72f373 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2050,6 +2050,17 @@ 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().
*/
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index d48b310c4760..11d24a552ee4 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -725,15 +725,6 @@ static int __device_attach_driver(struct device_driver *drv, void *_data)
bool async_allowed;
int ret;
- /*
- * Check if device has already been claimed. This may
- * happen with driver loading, device discovery/registration,
- * and deferred probe processing happens all at once with
- * multiple threads.
- */
- if (dev->driver)
- return -EBUSY;
-
ret = driver_match_device(drv, dev);
if (ret == 0) {
/* no match */
@@ -768,6 +759,15 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
device_lock(dev);
+ /*
+ * Check if device has already been removed or claimed. This may
+ * happen with driver loading, device discovery/registration,
+ * and deferred probe processing happens all at once with
+ * multiple threads.
+ */
+ if (dev->p->dead || dev->driver)
+ goto out_unlock;
+
if (dev->parent)
pm_runtime_get_sync(dev->parent);
@@ -778,7 +778,7 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
if (dev->parent)
pm_runtime_put(dev->parent);
-
+out_unlock:
device_unlock(dev);
put_device(dev);
@@ -891,7 +891,7 @@ static int __driver_attach(struct device *dev, void *data)
if (dev->parent && dev->bus->need_parent_lock)
device_lock(dev->parent);
device_lock(dev);
- if (!dev->driver)
+ if (!dev->p->dead && !dev->driver)
driver_probe_device(drv, dev);
device_unlock(dev);
if (dev->parent && dev->bus->need_parent_lock)
