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authorTomas Winkler <tomas.winkler@intel.com>2015-07-08 00:22:03 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-07-07 15:04:12 -0700
commit4f273959b850569253299987eee611927f048de7 (patch)
tree384abc27b134c3570ad8bcc7b6461e4128e7ed6a /drivers/misc
parentc7e9ad7da219cf3f8a7cc45eb1c02fdd91199e8d (diff)
mei: nfc: fix deadlock on shutdown/suspend path
In function mei_nfc_host_exit mei_cl_remove_device cannot be called under the device mutex as device removing flow invokes the device driver remove handler that calls in turn to mei_cl_disable_device which naturally acquires the device mutex. Also remove mei_cl_bus_remove_devices which has the same issue, but is never executed as currently the only device on the mei client bus is NFC and a new device cannot be easily added till the bus revamp is completed. This fixes regression caused by commit be9b720a0ccb ("mei_phy: move all nfc logic from mei driver to nfc") Prior to this change the nfc driver remove handler called to no-op disable function while actual nfc device was disabled directly from the mei driver. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/mei/bus.c16
-rw-r--r--drivers/misc/mei/init.c2
-rw-r--r--drivers/misc/mei/nfc.c3
3 files changed, 2 insertions, 19 deletions
diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 357b6ae4d207..458aa5a09c52 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -552,22 +552,6 @@ void mei_cl_bus_rx_event(struct mei_cl *cl)
schedule_work(&device->event_work);
}
-void mei_cl_bus_remove_devices(struct mei_device *dev)
-{
- struct mei_cl *cl, *next;
-
- mutex_lock(&dev->device_lock);
- list_for_each_entry_safe(cl, next, &dev->device_list, device_link) {
- if (cl->device)
- mei_cl_remove_device(cl->device);
-
- list_del(&cl->device_link);
- mei_cl_unlink(cl);
- kfree(cl);
- }
- mutex_unlock(&dev->device_lock);
-}
-
int __init mei_cl_bus_init(void)
{
return bus_register(&mei_cl_bus_type);
diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index 94514b2c7a50..00c3865ca3b1 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -333,8 +333,6 @@ void mei_stop(struct mei_device *dev)
mei_nfc_host_exit(dev);
- mei_cl_bus_remove_devices(dev);
-
mutex_lock(&dev->device_lock);
mei_wd_stop(dev);
diff --git a/drivers/misc/mei/nfc.c b/drivers/misc/mei/nfc.c
index b983c4ecad38..290ef3037437 100644
--- a/drivers/misc/mei/nfc.c
+++ b/drivers/misc/mei/nfc.c
@@ -402,11 +402,12 @@ void mei_nfc_host_exit(struct mei_device *dev)
cldev->priv_data = NULL;
- mutex_lock(&dev->device_lock);
/* Need to remove the device here
* since mei_nfc_free will unlink the clients
*/
mei_cl_remove_device(cldev);
+
+ mutex_lock(&dev->device_lock);
mei_nfc_free(ndev);
mutex_unlock(&dev->device_lock);
}