SUNRPC: Eliminate side effects from rpc_malloc

Currently rpc_malloc sets req->rq_buffer internally.  Make this a more
generic interface:  return a pointer to the new buffer (or NULL) and
make the caller set req->rq_buffer and req->rq_bufsize.  This looks much
more like kmalloc and eliminates the side effects.

To fix a potential deadlock, this patch also replaces GFP_NOFS with
GFP_NOWAIT in rpc_malloc.  This prevents async RPCs from sleeping outside
the RPC's task scheduler while allocating their buffer.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 3069ecca0129..2047fb202a13 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -264,7 +264,7 @@ struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *);
 void            rpc_wake_up_status(struct rpc_wait_queue *, int);
 void            rpc_delay(struct rpc_task *, unsigned long);
 void *          rpc_malloc(struct rpc_task *, size_t);
-void            rpc_free(struct rpc_task *);
+void            rpc_free(void *);
 int             rpciod_up(void);
 void            rpciod_down(void);
 int             __rpc_wait_for_completion_task(struct rpc_task *task, int (*)(void *));
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 7aa29502b187..745afc1d3068 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -114,7 +114,7 @@ struct rpc_xprt_ops {
         void            (*set_port)(struct rpc_xprt *xprt, unsigned short port);
         void            (*connect)(struct rpc_task *task);
         void *          (*buf_alloc)(struct rpc_task *task, size_t size);
-        void            (*buf_free)(struct rpc_task *task);
+        void            (*buf_free)(void *buffer);
         int             (*send_request)(struct rpc_task *task);
         void            (*set_retrans_timeout)(struct rpc_task *task);
         void            (*timer)(struct rpc_task *task);