> -----Original Message-----
> From: Myklebust, Trond
> Sent: Thursday, June 04, 2009 12:40 PM
> To: Benny Halevy
> Cc: linux-nfs@xxxxxxxxxxxxxxx; pnfs@xxxxxxxxxxxxx
> Subject: Re: [pnfs] [RFC 09/39] nfs41: New xs_tcp_read_data()
>
> On Fri, 2009-05-01 at 02:20 +0300, Benny Halevy wrote:
> > From: Ricardo Labiaga <Ricardo.Labiaga@xxxxxxxxxx>
> >
> > Handles RPC replies and backchannel callbacks. Traditionally the
NFS
> > client has expected only RPC replies on its open connections. With
> > NFSv4.1, callbacks can arrive over an existing open connection.
> >
> > This patch refactors the old xs_tcp_read_request() into an RPC reply
> handler:
> > xs_tcp_read_reply(), a new backchannel callback handler:
> xs_tcp_read_callback(),
> > and a common routine to read the data off the transport:
> xs_tcp_read_common().
> > The new xs_tcp_read_callback() queues callback requests onto a queue
> where
> > the callback service (a separate thread) is listening for the
> processing.
> >
> > This patch incorporates work and suggestions from Rahul Iyer
> (iyer@xxxxxxxxxx)
> > and Benny Halevy (bhalevy@xxxxxxxxxxx).
> >
> > [nfs41: Keep track of RPC call/reply direction with a flag]
> > [nfs41: Preallocate rpc_rqst receive buffer for handling callbacks]
> > Signed-off-by: Ricardo Labiaga <ricardo.labiaga@xxxxxxxxxx>
> > Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> > ---
> > net/sunrpc/xprtsock.c | 141
> ++++++++++++++++++++++++++++++++++++++++++------
> > 1 files changed, 123 insertions(+), 18 deletions(-)
> >
> > diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> > index 692b517..403ebda 100644
> > --- a/net/sunrpc/xprtsock.c
> > +++ b/net/sunrpc/xprtsock.c
> > @@ -34,6 +34,9 @@
> > #include <linux/sunrpc/sched.h>
> > #include <linux/sunrpc/xprtsock.h>
> > #include <linux/file.h>
> > +#ifdef CONFIG_NFS_V4_1
> > +#include <linux/sunrpc/bc_xprt.h>
> > +#endif
> >
> > #include <net/sock.h>
> > #include <net/checksum.h>
> > @@ -1028,25 +1031,16 @@ static inline void
xs_tcp_read_calldir(struct
> sock_xprt *transport,
> > xs_tcp_check_fraghdr(transport);
> > }
> >
> > -static inline void xs_tcp_read_request(struct rpc_xprt *xprt,
struct
> xdr_skb_reader *desc)
> > +static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
> > + struct xdr_skb_reader *desc,
> > + struct rpc_rqst *req)
> > {
> > - struct sock_xprt *transport = container_of(xprt, struct
sock_xprt,
> xprt);
> > - struct rpc_rqst *req;
> > + struct sock_xprt *transport =
> > + container_of(xprt, struct sock_xprt,
xprt);
> > struct xdr_buf *rcvbuf;
> > size_t len;
> > ssize_t r;
> >
> > - /* Find and lock the request corresponding to this xid */
> > - spin_lock(&xprt->transport_lock);
> > - req = xprt_lookup_rqst(xprt, transport->tcp_xid);
> > - if (!req) {
> > - transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
> > - dprintk("RPC: XID %08x request not found!\n",
> > - ntohl(transport->tcp_xid));
> > - spin_unlock(&xprt->transport_lock);
> > - return;
> > - }
> > -
> > rcvbuf = &req->rq_private_buf;
> > len = desc->count;
> > if (len > transport->tcp_reclen - transport->tcp_offset) {
> > @@ -1084,7 +1078,7 @@ static inline void xs_tcp_read_request(struct
> rpc_xprt *xprt, struct xdr_skb_rea
> > "tcp_offset = %u, tcp_reclen = %u\n",
> > xprt, transport->tcp_copied,
> > transport->tcp_offset,
transport->tcp_reclen);
> > - goto out;
> > + return;
> > }
> >
> > dprintk("RPC: XID %08x read %Zd bytes\n",
> > @@ -1100,11 +1094,122 @@ static inline void
xs_tcp_read_request(struct
> rpc_xprt *xprt, struct xdr_skb_rea
> > transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
> > }
> >
> > -out:
> > + return;
> > +}
> > +
> > +/*
> > + * Finds the request corresponding to the RPC xid and invokes the
> common
> > + * tcp read code to read the data.
> > + */
> > +static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
> > + struct xdr_skb_reader *desc)
> > +{
> > + struct sock_xprt *transport =
> > + container_of(xprt, struct sock_xprt,
xprt);
> > + struct rpc_rqst *req;
> > +
> > + dprintk("RPC: read reply XID %08x\n", ntohl(transport-
> >tcp_xid));
> > +
> > + /* Find and lock the request corresponding to this xid */
> > + spin_lock(&xprt->transport_lock);
> > + req = xprt_lookup_rqst(xprt, transport->tcp_xid);
> > + if (!req) {
> > + dprintk("RPC: XID %08x request not found!\n",
> > + ntohl(transport->tcp_xid));
> > + spin_unlock(&xprt->transport_lock);
> > + return -1;
> > + }
> > +
> > + xs_tcp_read_common(xprt, desc, req);
> > +
> > if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
> > xprt_complete_rqst(req->rq_task, transport->tcp_copied);
> > +
> > spin_unlock(&xprt->transport_lock);
> > - xs_tcp_check_fraghdr(transport);
> > + return 0;
> > +}
> > +
> > +#if defined(CONFIG_NFS_V4_1)
> > +/*
> > + * Obtains an rpc_rqst previously allocated and invokes the common
> > + * tcp read code to read the data. The result is placed in the
> callback
> > + * queue.
> > + * If we're unable to obtain the rpc_rqst we schedule the closing
of
> the
> > + * connection and return -1.
> > + */
> > +static inline int xs_tcp_read_callback(struct rpc_xprt *xprt,
> > + struct xdr_skb_reader *desc)
> > +{
> > + struct sock_xprt *transport =
> > + container_of(xprt, struct sock_xprt,
xprt);
> > + struct rpc_rqst *req;
> > +
> > + req = xprt_alloc_bc_request(xprt);
> > + if (req == NULL) {
> > + /*
> > + * Schedule an autoclose RPC call
> > + */
> > + printk(KERN_WARNING "Callback slot table overflowed\n");
> > + set_bit(XPRT_CLOSE_WAIT, &xprt->state);
> > + if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
> > + queue_work(rpciod_workqueue,
&xprt->task_cleanup);
> > + return -1;
> > + }
> > +
> > + req->rq_xid = transport->tcp_xid;
> > + dprintk("RPC: read callback XID %08x\n",
ntohl(req->rq_xid));
> > + xs_tcp_read_common(xprt, desc, req);
> > +
> > + if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) {
> > + struct svc_serv *bc_serv = xprt->bc_serv;
> > +
> > + /*
> > + * Add callback request to callback list. The callback
> > + * service sleeps on the sv_cb_waitq waiting for new
> > + * requests. Wake it up after adding enqueing the
> > + * request.
> > + */
> > + dprintk("RPC: add callback request to list\n");
> > + spin_lock(&bc_serv->sv_cb_lock);
> > + list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
> > + spin_unlock(&bc_serv->sv_cb_lock);
> > + wake_up(&bc_serv->sv_cb_waitq);
> > + }
> > +
> > + req->rq_private_buf.len = transport->tcp_copied;
> > +
> > + return 0;
> > +}
> > +#endif /* CONFIG_NFS_V4_1 */
> > +
> > +/*
> > + * Read data off the transport. This can be either an RPC_CALL or
an
> > + * RPC_REPLY. Relay the processing to helper functions.
> > + */
> > +static void xs_tcp_read_data(struct rpc_xprt *xprt,
> > + struct xdr_skb_reader *desc)
> > +{
> > + struct sock_xprt *transport =
> > + container_of(xprt, struct sock_xprt,
xprt);
> > + int status;
> > +
> > +#if defined(CONFIG_NFS_V4_1)
> > + status = (transport->tcp_flags & TCP_RPC_REPLY) ?
> > + xs_tcp_read_reply(xprt, desc) :
> > + xs_tcp_read_callback(xprt, desc);
> > +#else
> > + status = xs_tcp_read_reply(xprt, desc);
> > +#endif /* CONFIG_NFS_V4_1 */
>
> Ugh... Please don't embed ifdefs in functions like this...
>
OK, so is it okay to use the CONF_NFS_V4_1 code and remove the ifdefs?
- ricardo
> > +
> > + if (status == 0)
> > + xs_tcp_check_fraghdr(transport);
> > + else {
> > + /*
> > + * The transport_lock protects the request handling.
> > + * There's no need to hold it to update the tcp_flags.
> > + */
> > + transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
> > + }
> > }
> >
> > static inline void xs_tcp_read_discard(struct sock_xprt *transport,
> struct xdr_skb_reader *desc)
> > @@ -1151,7 +1256,7 @@ static int xs_tcp_data_recv(read_descriptor_t
> *rd_desc, struct sk_buff *skb, uns
> > }
> > /* Read in the request data */
> > if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
> > - xs_tcp_read_request(xprt, &desc);
> > + xs_tcp_read_data(xprt, &desc);
> > continue;
> > }
> > /* Skip over any trailing bytes on short reads */
>
> --
> Trond Myklebust
> Linux NFS client maintainer
>
> NetApp
> Trond.Myklebust@xxxxxxxxxx
> www.netapp.com
> _______________________________________________
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> pNFS@xxxxxxxxxxxxx
> http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
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