SUNRPC: Ensure the bvecs are reset when we re-encode the RPC request

The bvec tracks the list of pages, so if the number of pages changes
due to a re-encode, we need to reset the bvec as well.

Fixes: 277e4ab7d530 ("SUNRPC: Simplify TCP receive code by switching...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+

3 files changed, 4 insertions, 2 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 79c849391cb9..d8679b6027e9 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1865,6 +1865,7 @@ rpc_xdr_encode(struct rpc_task *task)
         req->rq_snd_buf.head[0].iov_len = 0;
         xdr_init_encode(&xdr, &req->rq_snd_buf,
                         req->rq_snd_buf.head[0].iov_base, req);
+        xdr_free_bvec(&req->rq_snd_buf);
         if (rpc_encode_header(task, &xdr))
                 return;
 
@@ -1904,8 +1905,6 @@ call_encode(struct rpc_task *task)
                         rpc_call_rpcerror(task, task->tk_status);
                 }
                 return;
-        } else {
-                xprt_request_prepare(task->tk_rqstp);
         }
 
         /* Add task to reply queue before transmission to avoid races */
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 70a704c44c6d..783748dc5e6f 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1041,6 +1041,8 @@ xprt_request_enqueue_receive(struct rpc_task *task)
 
         if (!xprt_request_need_enqueue_receive(task, req))
                 return;
+
+        xprt_request_prepare(task->tk_rqstp);
         spin_lock(&xprt->queue_lock);
 
         /* Update the softirq receive buffer */
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 6b1fca51028a..e2176c167a57 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -909,6 +909,7 @@ static int xs_nospace(struct rpc_rqst *req)
 static void
 xs_stream_prepare_request(struct rpc_rqst *req)
 {
+        xdr_free_bvec(&req->rq_rcv_buf);
         req->rq_task->tk_status = xdr_alloc_bvec(&req->rq_rcv_buf, GFP_KERNEL);
 }