[RFC v7 5/7] powerpc/mobility: Add lock/unlock device hotplug

[Michael Bringmann]

powerpc/mobility: Add device lock/unlock to PowerPC 'mobility' operation
to delay the operation of CPU DLPAR work queue operations by the 'readd'
activity until after any changes to the corresponding device-tree
properties have been written.

Signed-off-by: Michael Bringmann <m...@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c 
b/arch/powerpc/platforms/pseries/mobility.c
index 8a8033a..6d98f84 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -283,6 +283,8 @@ int pseries_devicetree_update(s32 scope)
        if (!rtas_buf)
                return -ENOMEM;
 
+       lock_device_hotplug();
+
        do {
                rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
                if (rc && rc != 1)
@@ -321,6 +323,7 @@ int pseries_devicetree_update(s32 scope)
        } while (rc == 1);
 
        kfree(rtas_buf);
+       unlock_device_hotplug();
        return rc;
 }