2007-09-10 18:03:15

by Talpey, Thomas

[permalink] [raw]
Subject: [PATCH 12/19] NFS/SUNRPC: support transport protocol naming

NFS/SUNRPC: support transport protocol naming

To prepare for including non-sockets-based RPC transports, select
RPC transports by an identifier (to be used in following patches).

Signed-off-by: Tom Talpey <[email protected]>

---

include/linux/sunrpc/xprt.h | 5 ++---
include/linux/sunrpc/xprtsock.h | 11 +++++++++++
net/sunrpc/clnt.c | 2 +-
net/sunrpc/xprt.c | 8 +++-----
net/sunrpc/xprtsock.c | 6 ++----
5 files changed, 19 insertions(+), 13 deletions(-)

Index: kernel/include/linux/sunrpc/xprt.h
===================================================================
--- kernel.orig/include/linux/sunrpc/xprt.h
+++ kernel/include/linux/sunrpc/xprt.h
@@ -187,7 +187,7 @@ struct rpc_xprt {
};

struct xprt_create {
- int proto; /* IPPROTO_UDP or IPPROTO_TCP */
+ int ident; /* XPRT_TRANSPORT identifier */
struct sockaddr * srcaddr; /* optional local address */
struct sockaddr * dstaddr; /* remote peer address */
size_t addrlen;
@@ -196,8 +196,7 @@ struct xprt_create {

struct xprt_class {
struct list_head list;
- unsigned short family;
- int protocol;
+ int ident; /* XPRT_TRANSPORT identifier */
struct rpc_xprt * (*setup)(struct xprt_create *);
struct module *owner;
char name[32];
Index: kernel/include/linux/sunrpc/xprtsock.h
===================================================================
--- kernel.orig/include/linux/sunrpc/xprtsock.h
+++ kernel/include/linux/sunrpc/xprtsock.h
@@ -19,6 +19,17 @@ int init_socket_xprt(void);
void cleanup_socket_xprt(void);

/*
+ * RPC transport identifiers for UDP, TCP
+ *
+ * To preserve compatibility with the historical use of raw IP protocol
+ * id's for transport selection, these are specified with the previous
+ * values. No such restriction exists for new transports, except that
+ * they may not collide with these values (17 and 6, respectively).
+ */
+#define XPRT_TRANSPORT_UDP IPPROTO_UDP
+#define XPRT_TRANSPORT_TCP IPPROTO_TCP
+
+/*
* RPC slot table sizes for UDP, TCP transports
*/
extern unsigned int xprt_udp_slot_table_entries;
Index: kernel/net/sunrpc/xprt.c
===================================================================
--- kernel.orig/net/sunrpc/xprt.c
+++ kernel/net/sunrpc/xprt.c
@@ -104,7 +104,7 @@ int xprt_register_transport(struct xprt_
spin_lock(&xprt_list_lock);
list_for_each_entry(t, &xprt_list, list) {
/* don't register the same transport class twice */
- if (t == transport)
+ if (t->ident == transport->ident)
goto out;
}

@@ -987,15 +987,13 @@ struct rpc_xprt *xprt_create_transport(s

spin_lock(&xprt_list_lock);
list_for_each_entry(t, &xprt_list, list) {
- if ((t->family == args->dstaddr->sa_family) &&
- (t->protocol == args->proto)) {
+ if (t->ident == args->ident) {
spin_unlock(&xprt_list_lock);
goto found;
}
}
spin_unlock(&xprt_list_lock);
- printk(KERN_ERR "RPC: transport (%u/%d) not supported\n",
- args->dstaddr->sa_family, args->proto);
+ printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident);
return ERR_PTR(-EIO);

found:
Index: kernel/net/sunrpc/xprtsock.c
===================================================================
--- kernel.orig/net/sunrpc/xprtsock.c
+++ kernel/net/sunrpc/xprtsock.c
@@ -1955,8 +1955,7 @@ static struct xprt_class xs_udp_transpor
.list = LIST_HEAD_INIT(xs_udp_transport.list),
.name = "udp",
.owner = THIS_MODULE,
- .family = AF_INET,
- .protocol = IPPROTO_UDP,
+ .ident = IPPROTO_UDP,
.setup = xs_setup_udp,
};

@@ -1964,8 +1963,7 @@ static struct xprt_class xs_tcp_transpor
.list = LIST_HEAD_INIT(xs_tcp_transport.list),
.name = "tcp",
.owner = THIS_MODULE,
- .family = AF_INET,
- .protocol = IPPROTO_TCP,
+ .ident = IPPROTO_TCP,
.setup = xs_setup_tcp,
};

Index: kernel/net/sunrpc/clnt.c
===================================================================
--- kernel.orig/net/sunrpc/clnt.c
+++ kernel/net/sunrpc/clnt.c
@@ -235,7 +235,7 @@ struct rpc_clnt *rpc_create(struct rpc_c
struct rpc_xprt *xprt;
struct rpc_clnt *clnt;
struct xprt_create xprtargs = {
- .proto = args->protocol,
+ .ident = args->protocol,
.srcaddr = args->saddress,
.dstaddr = args->address,
.addrlen = args->addrsize,

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2007-09-11 12:17:11

by Talpey, Thomas

[permalink] [raw]
Subject: Re: [PATCH 12/19] NFS/SUNRPC: support transport protocol naming

At 08:25 PM 9/10/2007, Chuck Lever wrote:
>Just a general comment.
>
>I don't see how this will make it easier to add NFS client support for
>new RPC transports. I thought we recently decided to pass down a
>string, and let the transports themselves register a netid that matches it?
>
>For example, these changes are required to support RDMA -- you can't
>just ship a new RDMA SUNRPC transport module and expect it to work
>without this ULP change. Likewise, if we add SCTP sometime in the
>future, will we want to make this same kind of modification to the NFS
>client before the SCTP SUNRCP transport module works correctly?

Well, the "string" discussion was in the context of the server-side
switch, but you call out a good goal to add transports without touching
the upper layers.

I think the choice of integer or string is basically arbitrary. One way or
the other, some mapping from identifier to the actual transport is defined.
Strings are a little more self-describing, but in the end harder to maintain
for that very reason. That's the way my thinking came down, anyway.

One way to allow extension would be to add a proto=%d syntax, this would
obviate having to change the many uses of xprt->prot and rpc_create()
in the in-kernel clients (another reason I chose to stick with int's). Happy
to code that...

Tom.

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