blob: c2f9165d13ef8438886004972f93fe2821b4c070 [file] [log] [blame]
Ursula Braun9bf9abe2017-01-09 16:55:21 +01001/*
2 * Shared Memory Communications over RDMA (SMC-R) and RoCE
3 *
4 * Link Layer Control (LLC)
5 *
6 * For now, we only support the necessary "confirm link" functionality
7 * which happens for the first RoCE link after successful CLC handshake.
8 *
9 * Copyright IBM Corp. 2016
10 *
11 * Author(s): Klaus Wacker <Klaus.Wacker@de.ibm.com>
12 * Ursula Braun <ubraun@linux.vnet.ibm.com>
13 */
14
15#include <net/tcp.h>
16#include <rdma/ib_verbs.h>
17
18#include "smc.h"
19#include "smc_core.h"
20#include "smc_clc.h"
21#include "smc_llc.h"
22
23/********************************** send *************************************/
24
25struct smc_llc_tx_pend {
26};
27
28/* handler for send/transmission completion of an LLC msg */
29static void smc_llc_tx_handler(struct smc_wr_tx_pend_priv *pend,
30 struct smc_link *link,
31 enum ib_wc_status wc_status)
32{
33 /* future work: handle wc_status error for recovery and failover */
34}
35
36/**
37 * smc_llc_add_pending_send() - add LLC control message to pending WQE transmits
38 * @link: Pointer to SMC link used for sending LLC control message.
39 * @wr_buf: Out variable returning pointer to work request payload buffer.
40 * @pend: Out variable returning pointer to private pending WR tracking.
41 * It's the context the transmit complete handler will get.
42 *
43 * Reserves and pre-fills an entry for a pending work request send/tx.
44 * Used by mid-level smc_llc_send_msg() to prepare for later actual send/tx.
45 * Can sleep due to smc_get_ctrl_buf (if not in softirq context).
46 *
47 * Return: 0 on success, otherwise an error value.
48 */
49static int smc_llc_add_pending_send(struct smc_link *link,
50 struct smc_wr_buf **wr_buf,
51 struct smc_wr_tx_pend_priv **pend)
52{
53 int rc;
54
55 rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, pend);
56 if (rc < 0)
57 return rc;
58 BUILD_BUG_ON_MSG(
59 sizeof(union smc_llc_msg) > SMC_WR_BUF_SIZE,
60 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_llc_msg)");
61 BUILD_BUG_ON_MSG(
62 sizeof(union smc_llc_msg) != SMC_WR_TX_SIZE,
63 "must adapt SMC_WR_TX_SIZE to sizeof(struct smc_llc_msg); if not all smc_wr upper layer protocols use the same message size any more, must start to set link->wr_tx_sges[i].length on each individual smc_wr_tx_send()");
64 BUILD_BUG_ON_MSG(
65 sizeof(struct smc_llc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
66 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_llc_tx_pend)");
67 return 0;
68}
69
70/* high-level API to send LLC confirm link */
71int smc_llc_send_confirm_link(struct smc_link *link, u8 mac[],
72 union ib_gid *gid,
73 enum smc_llc_reqresp reqresp)
74{
75 struct smc_link_group *lgr = container_of(link, struct smc_link_group,
76 lnk[SMC_SINGLE_LINK]);
77 struct smc_llc_msg_confirm_link *confllc;
78 struct smc_wr_tx_pend_priv *pend;
79 struct smc_wr_buf *wr_buf;
80 int rc;
81
82 rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
83 if (rc)
84 return rc;
85 confllc = (struct smc_llc_msg_confirm_link *)wr_buf;
86 memset(confllc, 0, sizeof(*confllc));
87 confllc->hd.common.type = SMC_LLC_CONFIRM_LINK;
88 confllc->hd.length = sizeof(struct smc_llc_msg_confirm_link);
89 if (reqresp == SMC_LLC_RESP)
90 confllc->hd.flags |= SMC_LLC_FLAG_RESP;
91 memcpy(confllc->sender_mac, mac, ETH_ALEN);
92 memcpy(confllc->sender_gid, gid, SMC_GID_SIZE);
93 hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
94 /* confllc->link_num = SMC_SINGLE_LINK; already done by memset above */
95 memcpy(confllc->link_uid, lgr->id, SMC_LGR_ID_SIZE);
96 confllc->max_links = SMC_LINKS_PER_LGR_MAX;
97 /* send llc message */
98 rc = smc_wr_tx_send(link, pend);
99 return rc;
100}
101
102/********************************* receive ***********************************/
103
104static void smc_llc_rx_confirm_link(struct smc_link *link,
105 struct smc_llc_msg_confirm_link *llc)
106{
107 struct smc_link_group *lgr;
108
109 lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
110 if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
111 if (lgr->role == SMC_SERV)
112 complete(&link->llc_confirm_resp);
113 } else {
114 if (lgr->role == SMC_CLNT) {
115 link->link_id = llc->link_num;
116 complete(&link->llc_confirm);
117 }
118 }
119}
120
121static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
122{
123 struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
124 union smc_llc_msg *llc = buf;
125
126 if (wc->byte_len < sizeof(*llc))
127 return; /* short message */
128 if (llc->raw.hdr.length != sizeof(*llc))
129 return; /* invalid message */
130 if (llc->raw.hdr.common.type == SMC_LLC_CONFIRM_LINK)
131 smc_llc_rx_confirm_link(link, &llc->confirm_link);
132}
133
134/***************************** init, exit, misc ******************************/
135
136static struct smc_wr_rx_handler smc_llc_rx_handlers[] = {
137 {
138 .handler = smc_llc_rx_handler,
139 .type = SMC_LLC_CONFIRM_LINK
140 },
141 {
142 .handler = NULL,
143 }
144};
145
146int __init smc_llc_init(void)
147{
148 struct smc_wr_rx_handler *handler;
149 int rc = 0;
150
151 for (handler = smc_llc_rx_handlers; handler->handler; handler++) {
152 INIT_HLIST_NODE(&handler->list);
153 rc = smc_wr_rx_register_handler(handler);
154 if (rc)
155 break;
156 }
157 return rc;
158}