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 } 159