From a5cda73e49aaaac58b25750f4b591c0dc9726a44 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 16 Mar 2020 14:53:04 -0400 Subject: [PATCH] SUNRPC: Restructure svc_tcp_recv_record() 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 --- 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 6d85bbb7b8b1..ec4ae34a1f84 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -1443,6 +1443,30 @@ 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 @@ out: } /* - * 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;