libnvdimm: Hold reference on parent while scheduling async init

commit b6eae0f61db27748606cc00dafcfd1e2c032f0a5 upstream.

Unlike asynchronous initialization in the core we have not yet associated
the device with the parent, and as such the device doesn't hold a reference
to the parent.

In order to resolve that we should be holding a reference on the parent
until the asynchronous initialization has completed.

Cc: <stable@vger.kernel.org>
Fixes: 4d88a97aa9e8 ("libnvdimm: ...base ... infrastructure")
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index fb5ab58..a6746a1 100644 (file)
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -484,6 +484,8 @@ static void nd_async_device_register(void *d, async_cookie_t cookie)
                put_device(dev);
        }
        put_device(dev);
+       if (dev->parent)
+               put_device(dev->parent);
 }
 
 static void nd_async_device_unregister(void *d, async_cookie_t cookie)
@@ -503,6 +505,8 @@ void __nd_device_register(struct device *dev)
        if (!dev)
                return;
        dev->bus = &nvdimm_bus_type;
+       if (dev->parent)
+               get_device(dev->parent);
        get_device(dev);
        async_schedule_domain(nd_async_device_register, dev,
                        &nd_async_domain);