AFS: Pass an afs_call* to call->async_workfn() instead of a work_struct*

call->async_workfn() can take an afs_call* arg rather than a work_struct* as
the functions assigned there are now called from afs_async_workfn() which has
to call container_of() anyway.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Nathaniel Wesley Filardo <nwf@cs.jhu.edu>
Reviewed-by: Tejun Heo <tj@kernel.org>
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index be75b50..590b55f 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -75,7 +75,7 @@
 	const struct afs_call_type *type;	/* type of call */
 	const struct afs_wait_mode *wait_mode;	/* completion wait mode */
 	wait_queue_head_t	waitq;		/* processes awaiting completion */
-	work_func_t		async_workfn;
+	void (*async_workfn)(struct afs_call *call); /* asynchronous work function */
 	struct work_struct	async_work;	/* asynchronous work processor */
 	struct work_struct	work;		/* actual work processor */
 	struct sk_buff_head	rx_queue;	/* received packets */