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// SPDX-License-Identifier: GPL-2.0
/*
* Shared Memory Communications over RDMA (SMC-R) and RoCE
*
* Link Layer Control (LLC)
*
* For now, we only support the necessary "confirm link" functionality
* which happens for the first RoCE link after successful CLC handshake.
*
* Copyright IBM Corp. 2016
*
* Author(s): Klaus Wacker <Klaus.Wacker@de.ibm.com>
* Ursula Braun <ubraun@linux.vnet.ibm.com>
*/
#include <net/tcp.h>
#include <rdma/ib_verbs.h>
#include "smc.h"
#include "smc_core.h"
#include "smc_clc.h"
#include "smc_llc.h"
#define SMC_LLC_DATA_LEN 40
struct smc_llc_hdr {
struct smc_wr_rx_hdr common;
u8 length; /* 44 */
u8 reserved;
u8 flags;
};
struct smc_llc_msg_confirm_link { /* type 0x01 */
struct smc_llc_hdr hd;
u8 sender_mac[ETH_ALEN];
u8 sender_gid[SMC_GID_SIZE];
u8 sender_qp_num[3];
u8 link_num;
u8 link_uid[SMC_LGR_ID_SIZE];
u8 max_links;
u8 reserved[9];
};
union smc_llc_msg {
struct smc_llc_msg_confirm_link confirm_link;
struct {
struct smc_llc_hdr hdr;
u8 data[SMC_LLC_DATA_LEN];
} raw;
};
#define SMC_LLC_FLAG_RESP 0x80
/********************************** send *************************************/
struct smc_llc_tx_pend {
};
/* handler for send/transmission completion of an LLC msg */
static void smc_llc_tx_handler(struct smc_wr_tx_pend_priv *pend,
struct smc_link *link,
enum ib_wc_status wc_status)
{
/* future work: handle wc_status error for recovery and failover */
}
/**
* smc_llc_add_pending_send() - add LLC control message to pending WQE transmits
* @link: Pointer to SMC link used for sending LLC control message.
* @wr_buf: Out variable returning pointer to work request payload buffer.
* @pend: Out variable returning pointer to private pending WR tracking.
* It's the context the transmit complete handler will get.
*
* Reserves and pre-fills an entry for a pending work request send/tx.
* Used by mid-level smc_llc_send_msg() to prepare for later actual send/tx.
* Can sleep due to smc_get_ctrl_buf (if not in softirq context).
*
* Return: 0 on success, otherwise an error value.
*/
static int smc_llc_add_pending_send(struct smc_link *link,
struct smc_wr_buf **wr_buf,
struct smc_wr_tx_pend_priv **pend)
{
int rc;
rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, pend);
if (rc < 0)
return rc;
BUILD_BUG_ON_MSG(
sizeof(union smc_llc_msg) > SMC_WR_BUF_SIZE,
"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_llc_msg)");
BUILD_BUG_ON_MSG(
sizeof(union smc_llc_msg) != SMC_WR_TX_SIZE,
"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()");
BUILD_BUG_ON_MSG(
sizeof(struct smc_llc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_llc_tx_pend)");
return 0;
}
/* high-level API to send LLC confirm link */
int smc_llc_send_confirm_link(struct smc_link *link, u8 mac[],
union ib_gid *gid,
enum smc_llc_reqresp reqresp)
{
struct smc_link_group *lgr = container_of(link, struct smc_link_group,
lnk[SMC_SINGLE_LINK]);
struct smc_llc_msg_confirm_link *confllc;
struct smc_wr_tx_pend_priv *pend;
struct smc_wr_buf *wr_buf;
int rc;
rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
if (rc)
return rc;
confllc = (struct smc_llc_msg_confirm_link *)wr_buf;
memset(confllc, 0, sizeof(*confllc));
confllc->hd.common.type = SMC_LLC_CONFIRM_LINK;
confllc->hd.length = sizeof(struct smc_llc_msg_confirm_link);
if (reqresp == SMC_LLC_RESP)
confllc->hd.flags |= SMC_LLC_FLAG_RESP;
memcpy(confllc->sender_mac, mac, ETH_ALEN);
memcpy(confllc->sender_gid, gid, SMC_GID_SIZE);
hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
/* confllc->link_num = SMC_SINGLE_LINK; already done by memset above */
memcpy(confllc->link_uid, lgr->id, SMC_LGR_ID_SIZE);
confllc->max_links = SMC_LINKS_PER_LGR_MAX;
/* send llc message */
rc = smc_wr_tx_send(link, pend);
return rc;
}
/********************************* receive ***********************************/
static void smc_llc_rx_confirm_link(struct smc_link *link,
struct smc_llc_msg_confirm_link *llc)
{
struct smc_link_group *lgr;
lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
if (lgr->role == SMC_SERV)
complete(&link->llc_confirm_resp);
} else {
if (lgr->role == SMC_CLNT) {
link->link_id = llc->link_num;
complete(&link->llc_confirm);
}
}
}
static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
{
struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
union smc_llc_msg *llc = buf;
if (wc->byte_len < sizeof(*llc))
return; /* short message */
if (llc->raw.hdr.length != sizeof(*llc))
return; /* invalid message */
if (llc->raw.hdr.common.type == SMC_LLC_CONFIRM_LINK)
smc_llc_rx_confirm_link(link, &llc->confirm_link);
}
/***************************** init, exit, misc ******************************/
static struct smc_wr_rx_handler smc_llc_rx_handlers[] = {
{
.handler = smc_llc_rx_handler,
.type = SMC_LLC_CONFIRM_LINK
},
{
.handler = NULL,
}
};
int __init smc_llc_init(void)
{
struct smc_wr_rx_handler *handler;
int rc = 0;
for (handler = smc_llc_rx_handlers; handler->handler; handler++) {
INIT_HLIST_NODE(&handler->list);
rc = smc_wr_rx_register_handler(handler);
if (rc)
break;
}
return rc;
}
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