On Nov. 10, 2008, 22:27 +0200, Benny Halevy <bhalevy@xxxxxxxxxxx> wrote:
> NFSv4.1 callbacks can arrive over an existing connection. This patch adds
> the logic to read the RPC call direction (call or reply). It does this by
> updating the state machine to look for the call direction invoking
> xs_tcp_read_calldir(...) after reading the XID.
>
> To avoid confusion, keep tcp_calldir in code in host order.
>
> Signed-off-by: Ricardo Labiaga <ricardo.labiaga@xxxxxxxxxx>
> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> ---
> net/sunrpc/xprtsock.c | 49 +++++++++++++++++++++++++++++++++++++++++++++----
> 1 files changed, 45 insertions(+), 4 deletions(-)
>
> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> index 0a50361..1ce05d7 100644
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -222,7 +222,8 @@ struct sock_xprt {
> * State of TCP reply receive
> */
> __be32 tcp_fraghdr,
> - tcp_xid;
> + tcp_xid,
> + tcp_calldir; /* Is this a call or a reply? */
>
> u32 tcp_offset,
> tcp_reclen;
> @@ -259,6 +260,7 @@ struct sock_xprt {
> #define TCP_RCV_COPY_FRAGHDR (1UL << 1)
> #define TCP_RCV_COPY_XID (1UL << 2)
> #define TCP_RCV_COPY_DATA (1UL << 3)
> +#define TCP_RCV_COPY_CALLDIR (1UL << 4)
>
> static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
> {
> @@ -919,7 +921,7 @@ static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_rea
> transport->tcp_offset = 0;
>
> /* Sanity check of the record length */
> - if (unlikely(transport->tcp_reclen < 4)) {
> + if (unlikely(transport->tcp_reclen < 8)) {
> dprintk("RPC: invalid TCP record fragment length\n");
> xprt_force_disconnect(xprt);
> return;
> @@ -954,13 +956,47 @@ static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_r
> if (used != len)
> return;
> transport->tcp_flags &= ~TCP_RCV_COPY_XID;
> - transport->tcp_flags |= TCP_RCV_COPY_DATA;
> + transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
> transport->tcp_copied = 4;
> - dprintk("RPC: reading reply for XID %08x\n",
> + dprintk("RPC: reading %s XID %08x\n",
> + (transport->tcp_calldir == RPC_REPLY) ? "reply for"
> + : "request with",
> ntohl(transport->tcp_xid));
> xs_tcp_check_fraghdr(transport);
> }
>
> +static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
> + struct xdr_skb_reader *desc)
> +{
> + size_t len, used;
> + u32 offset;
> + char *p;
> +
> + /*
> + * We want transport->tcp_offset to be 8 at the end of this routine
> + * (4 bytes for the xid and 4 bytes for the call/reply flag).
> + * When this function is called for the first time,
> + * transport->tcp_offset is 4 (after having already read the xid).
> + */
> + offset = transport->tcp_offset - sizeof(transport->tcp_xid);
> + len = sizeof(transport->tcp_calldir) - offset;
> + dprintk("RPC: reading CALL/REPLY flag (%Zu bytes)\n", len);
> + p = ((char *) &transport->tcp_calldir) + offset;
> + used = xdr_skb_read_bits(desc, p, len);
> + transport->tcp_offset += used;
> + if (used != len)
> + return;
> + transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
> + transport->tcp_flags |= TCP_RCV_COPY_DATA;
> + transport->tcp_copied += 4;
> + transport->tcp_calldir = ntohl(transport->tcp_calldir);
review 11-14: introduce direction flag, no need to save the
actual value of calldir.
> + dprintk("RPC: reading %s CALL/REPLY flag %08x\n",
> + (transport->tcp_calldir == RPC_REPLY) ? "reply for"
> + : "request with",
> + transport->tcp_calldir);
> + xs_tcp_check_fraghdr(transport);
> +}
> +
> static inline void xs_tcp_read_request(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
> {
> struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
> @@ -1077,6 +1113,11 @@ static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, uns
> xs_tcp_read_xid(transport, &desc);
> continue;
> }
> + /* Read in the call/reply flag */
> + if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
> + xs_tcp_read_calldir(transport, &desc);
> + continue;
> + }
> /* Read in the request data */
> if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
> xs_tcp_read_request(xprt, &desc);
--
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