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9bf9abea UB |
1 | /* |
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 | ||
25 | struct smc_llc_tx_pend { | |
26 | }; | |
27 | ||
28 | /* handler for send/transmission completion of an LLC msg */ | |
29 | static 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 | */ | |
49 | static 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 */ | |
71 | int 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 | ||
104 | static 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 | ||
121 | static 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 | ||
136 | static 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 | ||
146 | int __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 | } |