Refactor: svc_recvfrom() is going to be converted to read into
bio_vecs in a moment. Unhook the only other caller,
svc_tcp_recv_record(), which just wants to read the 4-byte stream
record marker into a kvec.
While we're in the area, streamline this helper by straight-lining
the hot path, replace dprintk call sites with tracepoints, and
reduce the number of atomic bit operations in this path.
Signed-off-by: Chuck Lever <[email protected]>
---
include/trace/events/sunrpc.h | 24 +++++++++++++++++++
net/sunrpc/svcsock.c | 51 ++++++++++++++++++++---------------------
2 files changed, 49 insertions(+), 26 deletions(-)
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 32200745f1b8..fd8073d1f3b8 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1459,6 +1459,30 @@ TRACE_EVENT(svcsock_new_socket,
)
);
+TRACE_EVENT(svcsock_marker,
+ TP_PROTO(
+ const struct svc_xprt *xprt,
+ __be32 marker
+ ),
+
+ TP_ARGS(xprt, marker),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, length)
+ __field(bool, last)
+ __string(addr, xprt->xpt_remotebuf)
+ ),
+
+ TP_fast_assign(
+ __entry->length = be32_to_cpu(marker) & RPC_FRAGMENT_SIZE_MASK;
+ __entry->last = be32_to_cpu(marker) & RPC_LAST_STREAM_FRAGMENT;
+ __assign_str(addr, xprt->xpt_remotebuf);
+ ),
+
+ TP_printk("addr=%s length=%u%s", __get_str(addr),
+ __entry->length, __entry->last ? " (last)" : "")
+);
+
DECLARE_EVENT_CLASS(svcsock_class,
TP_PROTO(
const struct svc_xprt *xprt,
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index d63b21f3f207..9c1eb13aa9b8 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -828,47 +828,45 @@ static void svc_tcp_clear_pages(struct svc_sock *svsk)
}
/*
- * Receive fragment record header.
- * If we haven't gotten the record length yet, get the next four bytes.
+ * Receive fragment record header into sk_marker.
*/
-static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
+static ssize_t svc_tcp_read_marker(struct svc_sock *svsk,
+ struct svc_rqst *rqstp)
{
- struct svc_serv *serv = svsk->sk_xprt.xpt_server;
- unsigned int want;
- int len;
+ ssize_t want, len;
+ /* If we haven't gotten the record length yet,
+ * get the next four bytes.
+ */
if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) {
+ struct msghdr msg = { NULL };
struct kvec iov;
want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
iov.iov_base = ((char *)&svsk->sk_marker) + svsk->sk_tcplen;
iov.iov_len = want;
- len = svc_recvfrom(rqstp, &iov, 1, want, 0);
+ iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, want);
+ len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
if (len < 0)
- goto error;
+ return len;
svsk->sk_tcplen += len;
-
if (len < want) {
- dprintk("svc: short recvfrom while reading record "
- "length (%d of %d)\n", len, want);
- return -EAGAIN;
+ /* call again to read the remaining bytes */
+ goto err_short;
}
-
- dprintk("svc: TCP record, %d bytes\n", svc_sock_reclen(svsk));
+ trace_svcsock_marker(&svsk->sk_xprt, svsk->sk_marker);
if (svc_sock_reclen(svsk) + svsk->sk_datalen >
- serv->sv_max_mesg) {
- net_notice_ratelimited("RPC: fragment too large: %d\n",
- svc_sock_reclen(svsk));
- goto err_delete;
- }
+ svsk->sk_xprt.xpt_server->sv_max_mesg)
+ goto err_too_large;
}
-
return svc_sock_reclen(svsk);
-error:
- dprintk("RPC: TCP recv_record got %d\n", len);
- return len;
-err_delete:
+
+err_too_large:
+ net_notice_ratelimited("svc: %s %s RPC fragment too large: %d\n",
+ __func__, svsk->sk_xprt.xpt_server->sv_name,
+ svc_sock_reclen(svsk));
set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
+err_short:
return -EAGAIN;
}
@@ -961,12 +959,13 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
test_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags),
test_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags));
- len = svc_tcp_recv_record(svsk, rqstp);
+ clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+ len = svc_tcp_read_marker(svsk, rqstp);
if (len < 0)
goto error;
base = svc_tcp_restore_pages(svsk, rqstp);
- want = svc_sock_reclen(svsk) - (svsk->sk_tcplen - sizeof(rpc_fraghdr));
+ want = len - (svsk->sk_tcplen - sizeof(rpc_fraghdr));
vec = rqstp->rq_vec;