[PATCH 1/2] nvdimm: Hold reference on parent while scheduling async init

From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org
Cc: vishal.l.verma@intel.com, dan.j.williams@intel.com,
	dave.jiang@intel.com, zwisler@kernel.org
Subject: [PATCH 1/2] nvdimm: Hold reference on parent while scheduling async init
Date: Tue, 25 Sep 2018 13:53:02 -0700	[thread overview]
Message-ID: <20180925205301.6182.58728.stgit@localhost.localdomain> (raw)
In-Reply-To: <20180925204801.6182.73167.stgit@localhost.localdomain>

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.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 drivers/nvdimm/bus.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 8aae6dcc839f..9148015ed803 100644
--- 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);

