memremap: pass a struct dev_pagemap to ->kill and ->cleanup

Passing the actual typed structure leads to more understandable code
vs just passing the ref member.

Reported-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 919755f..b8666a0 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -74,12 +74,12 @@ struct dev_pagemap_ops {
 	/*
 	 * Transition the refcount in struct dev_pagemap to the dead state.
 	 */
-	void (*kill)(struct percpu_ref *ref);
+	void (*kill)(struct dev_pagemap *pgmap);
 
 	/*
 	 * Wait for refcount in struct dev_pagemap to be idle and reap it.
 	 */
-	void (*cleanup)(struct percpu_ref *ref);
+	void (*cleanup)(struct dev_pagemap *pgmap);
 };
 
 /**