Add an additional bit flag to the device 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.
Signed-off-by: Alexander Duyck <alexander.h.du...@linux.intel.com>
---
drivers/base/core.c | 11 +++++++++++
drivers/base/dd.c | 8 ++++++--
include/linux/device.h | 5 +++++
3 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index f3e6ca4170b4..70358327303b 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2075,6 +2075,17 @@ 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->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 88713f182086..3bb8c3e0f3da 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -774,6 +774,10 @@ static void __device_attach_async_helper(void *_dev,
async_cookie_t cookie)
device_lock(dev);
+ /* device is or has been removed from the bus, just bail out */
+ if (dev->dead)
+ goto out_unlock;
+
if (dev->parent)
pm_runtime_get_sync(dev->parent);
@@ -784,7 +788,7 @@ 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);
@@ -897,7 +901,7 @@ 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->dead && !dev->driver)
driver_probe_device(drv, dev);
device_unlock(dev);
if (dev->parent && dev->bus->need_parent_lock)
diff --git a/include/linux/device.h b/include/linux/device.h
index 4921a6192f6b..393704e5b602 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -957,6 +957,10 @@ struct dev_links_info {
* device.
* @dma_coherent: this particular device is dma coherent, even if the
* architecture supports non-coherent devices.
+ * @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.
*
* At the lowest level, every device in a Linux system is represented by an
* instance of struct device. The device structure contains the information
@@ -1051,6 +1055,7 @@ struct device {
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
bool dma_coherent:1;
#endif
+ bool dead:1;
};
static inline struct device *kobj_to_dev(struct kobject *kobj)
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