SUNRPC: Chunk reading of replies from the server

Read the TCP data in chunks of max 2MB so that we do not hog the
socket lock.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 6d0cc3b8f932c35f47adb2b08a6a34a755ef8900..620be573d78b49e4730b3cffb0e3d31788971096 100644 (file)
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -52,6 +52,8 @@
 
 #include "sunrpc.h"
 
+#define RPC_TCP_READ_CHUNK_SZ  (3*512*1024)
+
 static void xs_close(struct rpc_xprt *xprt);
 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
                struct socket *sock);
@@ -1479,6 +1481,7 @@ static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, uns
                .offset = offset,
                .count  = len,
        };
+       size_t ret;
 
        dprintk("RPC:       xs_tcp_data_recv started\n");
        do {
@@ -1507,9 +1510,14 @@ static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, uns
                /* Skip over any trailing bytes on short reads */
                xs_tcp_read_discard(transport, &desc);
        } while (desc.count);
+       ret = len - desc.count;
+       if (ret < rd_desc->count)
+               rd_desc->count -= ret;
+       else
+               rd_desc->count = 0;
        trace_xs_tcp_data_recv(transport);
        dprintk("RPC:       xs_tcp_data_recv done\n");
-       return len - desc.count;
+       return ret;
 }
 
 static void xs_tcp_data_receive(struct sock_xprt *transport)
@@ -1517,7 +1525,6 @@ static void xs_tcp_data_receive(struct sock_xprt *transport)
        struct rpc_xprt *xprt = &transport->xprt;
        struct sock *sk;
        read_descriptor_t rd_desc = {
-               .count = 2*1024*1024,
                .arg.data = xprt,
        };
        unsigned long total = 0;
@@ -1531,16 +1538,16 @@ static void xs_tcp_data_receive(struct sock_xprt *transport)
 
        /* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
        for (loop = 0; loop < 64; loop++) {
+               rd_desc.count = RPC_TCP_READ_CHUNK_SZ;
                lock_sock(sk);
                read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
-               if (read <= 0) {
+               if (rd_desc.count != 0 || read < 0) {
                        clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
                        release_sock(sk);
                        break;
                }
                release_sock(sk);
                total += read;
-               rd_desc.count = 65536;
        }
        if (test_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
                queue_work(xprtiod_workqueue, &transport->recv_worker);