From: Axel Lin <axel.lin@ingics.com>
Date: Wed, 16 Sep 2015 13:25:38 +0000 (+0800)
Subject: libnvdimm: pfn_devs: Fix locking in namespace_store
X-Git-Tag: firefly_0821_release~176^2~1034^2~2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4ca8b57a0af145f4e791f21dbca6ad789da9ee8b;p=firefly-linux-kernel-4.4.55.git

libnvdimm: pfn_devs: Fix locking in namespace_store

Always take device_lock() before nvdimm_bus_lock() to prevent deadlock.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 3fd7d0d81a47..71805a1aa0f3 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -148,13 +148,13 @@ static ssize_t namespace_store(struct device *dev,
 	struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 	ssize_t rc;
 
-	nvdimm_bus_lock(dev);
 	device_lock(dev);
+	nvdimm_bus_lock(dev);
 	rc = nd_namespace_store(dev, &nd_pfn->ndns, buf, len);
 	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
-	device_unlock(dev);
 	nvdimm_bus_unlock(dev);
+	device_unlock(dev);
 
 	return rc;
 }