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-rw-r--r--drivers/rpmsg/virtio_rpmsg_bus.c36
1 files changed, 34 insertions, 2 deletions
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 75506ec2840e..9623327ba509 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -188,6 +188,26 @@ static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
rpdev->id.name);
}
+/**
+ * __ept_release() - deallocate an rpmsg endpoint
+ * @kref: the ept's reference count
+ *
+ * This function deallocates an ept, and is invoked when its @kref refcount
+ * drops to zero.
+ *
+ * Never invoke this function directly!
+ */
+static void __ept_release(struct kref *kref)
+{
+ struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
+ refcount);
+ /*
+ * At this point no one holds a reference to ept anymore,
+ * so we can directly free it
+ */
+ kfree(ept);
+}
+
/* for more info, see below documentation of rpmsg_create_ept() */
static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb,
@@ -206,6 +226,8 @@ static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
return NULL;
}
+ kref_init(&ept->refcount);
+
ept->rpdev = rpdev;
ept->cb = cb;
ept->priv = priv;
@@ -238,7 +260,7 @@ rem_idr:
idr_remove(&vrp->endpoints, request);
free_ept:
mutex_unlock(&vrp->endpoints_lock);
- kfree(ept);
+ kref_put(&ept->refcount, __ept_release);
return NULL;
}
@@ -306,7 +328,7 @@ __rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
idr_remove(&vrp->endpoints, ept->addr);
mutex_unlock(&vrp->endpoints_lock);
- kfree(ept);
+ kref_put(&ept->refcount, __ept_release);
}
/**
@@ -790,7 +812,13 @@ static void rpmsg_recv_done(struct virtqueue *rvq)
/* use the dst addr to fetch the callback of the appropriate user */
mutex_lock(&vrp->endpoints_lock);
+
ept = idr_find(&vrp->endpoints, msg->dst);
+
+ /* let's make sure no one deallocates ept while we use it */
+ if (ept)
+ kref_get(&ept->refcount);
+
mutex_unlock(&vrp->endpoints_lock);
if (ept && ept->cb)
@@ -798,6 +826,10 @@ static void rpmsg_recv_done(struct virtqueue *rvq)
else
dev_warn(dev, "msg received with no recepient\n");
+ /* farewell, ept, we don't need you anymore */
+ if (ept)
+ kref_put(&ept->refcount, __ept_release);
+
/* publish the real size of the buffer */
sg_init_one(&sg, msg, RPMSG_BUF_SIZE);