[PATCH v6 4/6] net/core: apply pm_runtime_set_memalloc_noio on network devices

[Ming Lei <ming.lei@canonical.com>]

Deadlock might be caused by allocating memory with GFP_KERNEL in
runtime_resume and runtime_suspend callback of network devices in
iSCSI situation, so mark network devices and its ancestor as
'memalloc_noio' with the introduced pm_runtime_set_memalloc_noio().

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Decotigny <david.decotigny@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
v4:
	 - call pm_runtime_set_memalloc_noio(ddev, true) after
	   device_add
---
 net/core/net-sysfs.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index bcf02f6..a55d255 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -22,6 +22,7 @@
 #include <linux/vmalloc.h>
 #include <linux/export.h>
 #include <linux/jiffies.h>
+#include <linux/pm_runtime.h>
 #include <net/wext.h>
 
 #include "net-sysfs.h"
@@ -1386,6 +1387,8 @@ void netdev_unregister_kobject(struct net_device * net)
 
 	remove_queue_kobjects(net);
 
+	pm_runtime_set_memalloc_noio(dev, false);
+
 	device_del(dev);
 }
 
@@ -1421,6 +1424,8 @@ int netdev_register_kobject(struct net_device *net)
 		return error;
 	}
 
+	pm_runtime_set_memalloc_noio(dev, true);
+
 	return error;
 }
 
-- 
1.7.9.5

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