RPC: Clean up RPC task structure

 Shrink the RPC task structure. Instead of storing separate pointers
 for task->tk_exit and task->tk_release, put them in a structure.

 Also pass the user data pointer as a parameter instead of passing it via
 task->tk_calldata. This enables us to nest callbacks.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 2516ade..4dff705 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -406,10 +406,12 @@
 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
 extern int  nfs_flush_incompatible(struct file *file, struct page *page);
 extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
-extern void nfs_writeback_done(struct rpc_task *task);
+extern void nfs_writeback_done(struct rpc_task *task, void *data);
+extern void nfs_writedata_release(void *data);
 
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
-extern void nfs_commit_done(struct rpc_task *);
+extern void nfs_commit_done(struct rpc_task *, void *data);
+extern void nfs_commit_release(void *data);
 #endif
 
 /*
@@ -481,7 +483,9 @@
 extern int  nfs_readpage(struct file *, struct page *);
 extern int  nfs_readpages(struct file *, struct address_space *,
 		struct list_head *, unsigned);
-extern void nfs_readpage_result(struct rpc_task *);
+extern void nfs_readpage_result(struct rpc_task *, void *);
+extern void  nfs_readdata_release(void *data);
+
 
 /*
  * Allocate and free nfs_read_data structures
@@ -501,8 +505,6 @@
 	mempool_free(p, nfs_rdata_mempool);
 }
 
-extern void  nfs_readdata_release(struct rpc_task *task);
-
 /*
  * linux/fs/nfs3proc.c
  */