[PATCH] RPC: skip over transport-specific heads automatically
Add a generic mechanism for skipping over transport-specific headers
when constructing an RPC request. This removes another "xprt->stream"
dependency.
Test-plan:
Write-intensive workload on a single mount point (try both UDP and
TCP).
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/msg_prot.h b/include/linux/sunrpc/msg_prot.h
index 15f1153..f43f237 100644
--- a/include/linux/sunrpc/msg_prot.h
+++ b/include/linux/sunrpc/msg_prot.h
@@ -76,5 +76,30 @@
#define RPC_MAXNETNAMELEN 256
+/*
+ * From RFC 1831:
+ *
+ * "A record is composed of one or more record fragments. A record
+ * fragment is a four-byte header followed by 0 to (2**31) - 1 bytes of
+ * fragment data. The bytes encode an unsigned binary number; as with
+ * XDR integers, the byte order is from highest to lowest. The number
+ * encodes two values -- a boolean which indicates whether the fragment
+ * is the last fragment of the record (bit value 1 implies the fragment
+ * is the last fragment) and a 31-bit unsigned binary value which is the
+ * length in bytes of the fragment's data. The boolean value is the
+ * highest-order bit of the header; the length is the 31 low-order bits.
+ * (Note that this record specification is NOT in XDR standard form!)"
+ *
+ * The Linux RPC client always sends its requests in a single record
+ * fragment, limiting the maximum payload size for stream transports to
+ * 2GB.
+ */
+
+typedef u32 rpc_fraghdr;
+
+#define RPC_LAST_STREAM_FRAGMENT (1U << 31)
+#define RPC_FRAGMENT_SIZE_MASK (~RPC_LAST_STREAM_FRAGMENT)
+#define RPC_MAX_FRAGMENT_SIZE ((1U << 31) - 1)
+
#endif /* __KERNEL__ */
#endif /* _LINUX_SUNRPC_MSGPROT_H_ */
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index e73174c..966c456 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -155,6 +155,8 @@
size_t max_payload; /* largest RPC payload size,
in bytes */
+ unsigned int tsh_size; /* size of transport specific
+ header */
struct rpc_wait_queue sending; /* requests waiting to send */
struct rpc_wait_queue resend; /* requests waiting to resend */
@@ -236,6 +238,11 @@
void xprt_release(struct rpc_task *task);
int xprt_destroy(struct rpc_xprt *xprt);
+static inline u32 *xprt_skip_transport_header(struct rpc_xprt *xprt, u32 *p)
+{
+ return p + xprt->tsh_size;
+}
+
/*
* Transport switch helper functions
*/
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 53a030a..d2b08f1 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -844,10 +844,8 @@
/* We compute the checksum for the verifier over the xdr-encoded bytes
* starting with the xid and ending at the end of the credential: */
- iov.iov_base = req->rq_snd_buf.head[0].iov_base;
- if (task->tk_client->cl_xprt->stream)
- /* See clnt.c:call_header() */
- iov.iov_base += 4;
+ iov.iov_base = xprt_skip_transport_header(task->tk_xprt,
+ req->rq_snd_buf.head[0].iov_base);
iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
xdr_buf_from_iov(&iov, &verf_buf);
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 4677959..cc1b773 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1075,13 +1075,12 @@
call_header(struct rpc_task *task)
{
struct rpc_clnt *clnt = task->tk_client;
- struct rpc_xprt *xprt = clnt->cl_xprt;
struct rpc_rqst *req = task->tk_rqstp;
u32 *p = req->rq_svec[0].iov_base;
/* FIXME: check buffer size? */
- if (xprt->stream)
- *p++ = 0; /* fill in later */
+
+ p = xprt_skip_transport_header(task->tk_xprt, p);
*p++ = req->rq_xid; /* XID */
*p++ = htonl(RPC_CALL); /* CALL */
*p++ = htonl(RPC_VERSION); /* RPC version */
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 5798830..aaf053b 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -282,6 +282,13 @@
return status;
}
+static inline void xs_encode_tcp_record_marker(struct xdr_buf *buf)
+{
+ u32 reclen = buf->len - sizeof(rpc_fraghdr);
+ rpc_fraghdr *base = buf->head[0].iov_base;
+ *base = htonl(RPC_LAST_STREAM_FRAGMENT | reclen);
+}
+
/**
* xs_tcp_send_request - write an RPC request to a TCP socket
* @task: address of RPC task that manages the state of an RPC request
@@ -301,11 +308,9 @@
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
struct xdr_buf *xdr = &req->rq_snd_buf;
- u32 *marker = req->rq_svec[0].iov_base;
int status, retry = 0;
- /* Write the record marker */
- *marker = htonl(0x80000000|(req->rq_slen-sizeof(*marker)));
+ xs_encode_tcp_record_marker(&req->rq_snd_buf);
xs_pktdump("packet data:",
req->rq_svec->iov_base,
@@ -503,16 +508,19 @@
xprt->tcp_offset += used;
if (used != len)
return;
+
xprt->tcp_reclen = ntohl(xprt->tcp_recm);
- if (xprt->tcp_reclen & 0x80000000)
+ if (xprt->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
xprt->tcp_flags |= XPRT_LAST_FRAG;
else
xprt->tcp_flags &= ~XPRT_LAST_FRAG;
- xprt->tcp_reclen &= 0x7fffffff;
+ xprt->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
+
xprt->tcp_flags &= ~XPRT_COPY_RECM;
xprt->tcp_offset = 0;
+
/* Sanity check of the record length */
- if (xprt->tcp_reclen < 4) {
+ if (unlikely(xprt->tcp_reclen < 4)) {
dprintk("RPC: invalid TCP record fragment length\n");
xprt_disconnect(xprt);
return;
@@ -1065,6 +1073,7 @@
xprt->prot = IPPROTO_UDP;
xprt->port = XS_MAX_RESVPORT;
+ xprt->tsh_size = 0;
xprt->stream = 0;
xprt->nocong = 0;
xprt->cwnd = RPC_INITCWND;
@@ -1105,11 +1114,12 @@
xprt->prot = IPPROTO_TCP;
xprt->port = XS_MAX_RESVPORT;
+ xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
xprt->stream = 1;
xprt->nocong = 1;
xprt->cwnd = RPC_MAXCWND(xprt);
xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
- xprt->max_payload = (1U << 31) - 1;
+ xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
INIT_WORK(&xprt->connect_worker, xs_tcp_connect_worker, xprt);