159 lines
4.9 KiB
C
159 lines
4.9 KiB
C
/*
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* Shared Memory Communications over RDMA (SMC-R) and RoCE
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*
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* Link Layer Control (LLC)
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*
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* For now, we only support the necessary "confirm link" functionality
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* which happens for the first RoCE link after successful CLC handshake.
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*
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* Copyright IBM Corp. 2016
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*
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* Author(s): Klaus Wacker <Klaus.Wacker@de.ibm.com>
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* Ursula Braun <ubraun@linux.vnet.ibm.com>
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*/
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#include <net/tcp.h>
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#include <rdma/ib_verbs.h>
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#include "smc.h"
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#include "smc_core.h"
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#include "smc_clc.h"
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#include "smc_llc.h"
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/********************************** send *************************************/
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struct smc_llc_tx_pend {
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};
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/* handler for send/transmission completion of an LLC msg */
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static void smc_llc_tx_handler(struct smc_wr_tx_pend_priv *pend,
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struct smc_link *link,
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enum ib_wc_status wc_status)
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{
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/* future work: handle wc_status error for recovery and failover */
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}
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/**
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* smc_llc_add_pending_send() - add LLC control message to pending WQE transmits
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* @link: Pointer to SMC link used for sending LLC control message.
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* @wr_buf: Out variable returning pointer to work request payload buffer.
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* @pend: Out variable returning pointer to private pending WR tracking.
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* It's the context the transmit complete handler will get.
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*
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* Reserves and pre-fills an entry for a pending work request send/tx.
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* Used by mid-level smc_llc_send_msg() to prepare for later actual send/tx.
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* Can sleep due to smc_get_ctrl_buf (if not in softirq context).
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*
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* Return: 0 on success, otherwise an error value.
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*/
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static int smc_llc_add_pending_send(struct smc_link *link,
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struct smc_wr_buf **wr_buf,
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struct smc_wr_tx_pend_priv **pend)
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{
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int rc;
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rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, pend);
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if (rc < 0)
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return rc;
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BUILD_BUG_ON_MSG(
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sizeof(union smc_llc_msg) > SMC_WR_BUF_SIZE,
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"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_llc_msg)");
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BUILD_BUG_ON_MSG(
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sizeof(union smc_llc_msg) != SMC_WR_TX_SIZE,
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"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()");
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BUILD_BUG_ON_MSG(
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sizeof(struct smc_llc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
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"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_llc_tx_pend)");
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return 0;
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}
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/* high-level API to send LLC confirm link */
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int smc_llc_send_confirm_link(struct smc_link *link, u8 mac[],
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union ib_gid *gid,
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enum smc_llc_reqresp reqresp)
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{
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struct smc_link_group *lgr = container_of(link, struct smc_link_group,
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lnk[SMC_SINGLE_LINK]);
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struct smc_llc_msg_confirm_link *confllc;
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struct smc_wr_tx_pend_priv *pend;
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struct smc_wr_buf *wr_buf;
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int rc;
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rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
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if (rc)
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return rc;
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confllc = (struct smc_llc_msg_confirm_link *)wr_buf;
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memset(confllc, 0, sizeof(*confllc));
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confllc->hd.common.type = SMC_LLC_CONFIRM_LINK;
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confllc->hd.length = sizeof(struct smc_llc_msg_confirm_link);
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if (reqresp == SMC_LLC_RESP)
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confllc->hd.flags |= SMC_LLC_FLAG_RESP;
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memcpy(confllc->sender_mac, mac, ETH_ALEN);
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memcpy(confllc->sender_gid, gid, SMC_GID_SIZE);
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hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
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/* confllc->link_num = SMC_SINGLE_LINK; already done by memset above */
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memcpy(confllc->link_uid, lgr->id, SMC_LGR_ID_SIZE);
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confllc->max_links = SMC_LINKS_PER_LGR_MAX;
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/* send llc message */
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rc = smc_wr_tx_send(link, pend);
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return rc;
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}
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/********************************* receive ***********************************/
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static void smc_llc_rx_confirm_link(struct smc_link *link,
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struct smc_llc_msg_confirm_link *llc)
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{
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struct smc_link_group *lgr;
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lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
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if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
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if (lgr->role == SMC_SERV)
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complete(&link->llc_confirm_resp);
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} else {
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if (lgr->role == SMC_CLNT) {
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link->link_id = llc->link_num;
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complete(&link->llc_confirm);
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}
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}
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}
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static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
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{
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struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
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union smc_llc_msg *llc = buf;
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if (wc->byte_len < sizeof(*llc))
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return; /* short message */
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if (llc->raw.hdr.length != sizeof(*llc))
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return; /* invalid message */
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if (llc->raw.hdr.common.type == SMC_LLC_CONFIRM_LINK)
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smc_llc_rx_confirm_link(link, &llc->confirm_link);
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}
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/***************************** init, exit, misc ******************************/
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static struct smc_wr_rx_handler smc_llc_rx_handlers[] = {
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{
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.handler = smc_llc_rx_handler,
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.type = SMC_LLC_CONFIRM_LINK
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},
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{
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.handler = NULL,
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}
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};
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int __init smc_llc_init(void)
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{
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struct smc_wr_rx_handler *handler;
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int rc = 0;
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for (handler = smc_llc_rx_handlers; handler->handler; handler++) {
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INIT_HLIST_NODE(&handler->list);
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rc = smc_wr_rx_register_handler(handler);
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if (rc)
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break;
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}
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return rc;
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}
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