xprtrdma: Clean up regbuf helpers

For code legibility, clean up the function names to be consistent
with the pattern: "rpcrdma" _ object-type _ action

Also rpcrdma_regbuf_alloc and rpcrdma_regbuf_free no longer have any
callers outside of verbs.c, and can thus be made static.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -550,25 +550,34 @@ struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
 void rpcrdma_buffer_put(struct rpcrdma_req *);
 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
 
-struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(size_t, enum dma_data_direction,
-					    gfp_t);
 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size,
 			    gfp_t flags);
-bool __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *, struct rpcrdma_regbuf *);
-void rpcrdma_free_regbuf(struct rpcrdma_regbuf *);
+bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
+			      struct rpcrdma_regbuf *rb);
 
-static inline bool
-rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
+/**
+ * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped
+ *
+ * Returns true if the buffer is now mapped to rb->rg_device.
+ */
+static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
 {
 	return rb->rg_device != NULL;
 }
 
-static inline bool
-rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
+/**
+ * rpcrdma_regbuf_dma_map - DMA-map a regbuf
+ * @r_xprt: controlling transport instance
+ * @rb: regbuf to be mapped
+ *
+ * Returns true if the buffer is currently DMA mapped.
+ */
+static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
+					  struct rpcrdma_regbuf *rb)
 {
 	if (likely(rpcrdma_regbuf_is_mapped(rb)))
 		return true;
-	return __rpcrdma_dma_map_regbuf(ia, rb);
+	return __rpcrdma_regbuf_dma_map(r_xprt, rb);
 }
 
 /*