xprtrdma: Clean up rpcrdma_create_req()

Eventually, I'd like to invoke rpcrdma_create_req() during the
call_reserve step. Memory allocation there probably needs to use
GFP_NOIO. Therefore a set of GFP flags needs to be passed in.

As an additional clean up, just return a pointer or NULL, because
the only error return code here is -ENOMEM.

Lastly, clean up the function names to be consistent with the
pattern: "rpcrdma" _ object-type _ action
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/backchannel.c

@@ -31,9 +31,9 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt,
 		struct rpcrdma_regbuf *rb;
 		size_t size;
 
-		req = rpcrdma_create_req(r_xprt);
-		if (IS_ERR(req))
-			return PTR_ERR(req);
+		req = rpcrdma_req_create(r_xprt, GFP_KERNEL);
+		if (!req)
+			return -ENOMEM;
 		rqst = &req->rl_slot;
 
 		rqst->rq_xprt = xprt;

net/sunrpc/xprtrdma/verbs.c

@@ -996,22 +996,27 @@ rpcrdma_mr_refresh_worker(struct work_struct *work)
 	rpcrdma_mrs_create(r_xprt);
 }
 
-struct rpcrdma_req *
-rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
+/**
+ * rpcrdma_req_create - Allocate an rpcrdma_req object
+ * @r_xprt: controlling r_xprt
+ * @flags: GFP flags passed to memory allocators
+ *
+ * Returns an allocated and fully initialized rpcrdma_req or NULL.
+ */
+struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, gfp_t flags)
 {
 	struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
 	struct rpcrdma_regbuf *rb;
 	struct rpcrdma_req *req;
 
-	req = kzalloc(sizeof(*req), GFP_KERNEL);
+	req = kzalloc(sizeof(*req), flags);
 	if (req == NULL)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
-	rb = rpcrdma_alloc_regbuf(RPCRDMA_HDRBUF_SIZE,
-				  DMA_TO_DEVICE, GFP_KERNEL);
+	rb = rpcrdma_alloc_regbuf(RPCRDMA_HDRBUF_SIZE, DMA_TO_DEVICE, flags);
 	if (IS_ERR(rb)) {
 		kfree(req);
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 	}
 	req->rl_rdmabuf = rb;
 	xdr_buf_init(&req->rl_hdrbuf, rb->rg_base, rdmab_length(rb));
@@ -1086,16 +1091,14 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
 
 	INIT_LIST_HEAD(&buf->rb_send_bufs);
 	INIT_LIST_HEAD(&buf->rb_allreqs);
+
+	rc = -ENOMEM;
 	for (i = 0; i < buf->rb_max_requests; i++) {
 		struct rpcrdma_req *req;
 
-		req = rpcrdma_create_req(r_xprt);
-		if (IS_ERR(req)) {
-			dprintk("RPC:       %s: request buffer %d alloc"
-				" failed\n", __func__, i);
-			rc = PTR_ERR(req);
+		req = rpcrdma_req_create(r_xprt, GFP_KERNEL);
+		if (!req)
 			goto out;
-		}
 		list_add(&req->rl_list, &buf->rb_send_bufs);
 	}
 

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -528,7 +528,8 @@ int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
 /*
  * Buffer calls - xprtrdma/verbs.c
  */
-struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
+struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt,
+				       gfp_t flags);
 void rpcrdma_req_destroy(struct rpcrdma_req *req);
 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);