SUNRPC refactor rpcauth_checkverf error returns

Most of the time an error from the credops crvalidate function means the
server has sent us a garbage verifier. The gss_validate function is the
exception where there is an -EACCES case if the user GSS_context on the client
has expired.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 631085f..0cd5b6d5 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2072,7 +2072,8 @@
 		dprintk("RPC: %5u %s: XDR representation not a multiple of"
 		       " 4 bytes: 0x%x\n", task->tk_pid, __func__,
 		       task->tk_rqstp->rq_rcv_buf.len);
-		goto out_eio;
+		error = -EIO;
+		goto out_err;
 	}
 	if ((len -= 3) < 0)
 		goto out_overflow;
@@ -2081,6 +2082,7 @@
 	if ((n = ntohl(*p++)) != RPC_REPLY) {
 		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
 			task->tk_pid, __func__, n);
+		error = -EIO;
 		goto out_garbage;
 	}
 
@@ -2099,7 +2101,8 @@
 			dprintk("RPC: %5u %s: RPC call rejected, "
 				"unknown error: %x\n",
 				task->tk_pid, __func__, n);
-			goto out_eio;
+			error = -EIO;
+			goto out_err;
 		}
 		if (--len < 0)
 			goto out_overflow;
@@ -2144,9 +2147,11 @@
 				task->tk_pid, __func__, n);
 		goto out_err;
 	}
-	if (!(p = rpcauth_checkverf(task, p))) {
-		dprintk("RPC: %5u %s: auth check failed\n",
-				task->tk_pid, __func__);
+	p = rpcauth_checkverf(task, p);
+	if (IS_ERR(p)) {
+		error = PTR_ERR(p);
+		dprintk("RPC: %5u %s: auth check failed with %d\n",
+				task->tk_pid, __func__, error);
 		goto out_garbage;		/* bad verifier, retry */
 	}
 	len = p - (__be32 *)iov->iov_base - 1;
@@ -2199,8 +2204,6 @@
 out_retry:
 		return ERR_PTR(-EAGAIN);
 	}
-out_eio:
-	error = -EIO;
 out_err:
 	rpc_exit(task, error);
 	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,