[PATCH 4.6 043/100] mei: bus: call mei_cl_read_start under device lock

Greg Kroah-Hartman
2016-05-30T21:11:15Z

From: Alexander Usyskin <alexander.usyskin@intel.com>

commit bc46b45a421a64a0895dd41a34d3d2086e1ac7f6 upstream.

Ensure that mei_cl_read_start is called under the device lock
also in the bus layer. The function updates global ctrl_wr_list
which should be locked.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/misc/mei/bus.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -220,17 +220,23 @@ EXPORT_SYMBOL_GPL(mei_cldev_recv);
static void mei_cl_bus_event_work(struct work_struct *work)
{
struct mei_cl_device *cldev;
+ struct mei_device *bus;

cldev = container_of(work, struct mei_cl_device, event_work);

+ bus = cldev->bus;
+
if (cldev->event_cb)
cldev->event_cb(cldev, cldev->events, cldev->event_context);

cldev->events = 0;

/* Prepare for the next read */
- if (cldev->events_mask & BIT(MEI_CL_EVENT_RX))
+ if (cldev->events_mask & BIT(MEI_CL_EVENT_RX)) {
+ mutex_lock(&bus->device_lock);
mei_cl_read_start(cldev->cl, 0, NULL);
+ mutex_unlock(&bus->device_lock);
+ }
}

/**
@@ -304,6 +310,7 @@ int mei_cldev_register_event_cb(struct m
unsigned long events_mask,
mei_cldev_event_cb_t event_cb, void *context)
{
+ struct mei_device *bus = cldev->bus;
int ret;

if (cldev->event_cb)
@@ -316,15 +323,17 @@ int mei_cldev_register_event_cb(struct m
INIT_WORK(&cldev->event_work, mei_cl_bus_event_work);

if (cldev->events_mask & BIT(MEI_CL_EVENT_RX)) {
+ mutex_lock(&bus->device_lock);
ret = mei_cl_read_start(cldev->cl, 0, NULL);
+ mutex_unlock(&bus->device_lock);
if (ret && ret != -EBUSY)
return ret;
}

if (cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)) {
- mutex_lock(&cldev->cl->dev->device_lock);
+ mutex_lock(&bus->device_lock);
ret = mei_cl_notify_request(cldev->cl, NULL, event_cb ? 1 : 0);
- mutex_unlock(&cldev->cl->dev->device_lock);
+ mutex_unlock(&bus->device_lock);
if (ret)
return ret;
}