libnvdimm: Hold reference on parent while scheduling async init

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>

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 8aae6dcc839fed90a76e31eaf35a5f47ac04957d..9148015ed8036fc59a3ada2f364b558bd58201d9 100644 (file)
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -488,6 +488,8 @@ 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)
@@ -507,6 +509,8 @@ 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);