[PATCH V2 net-next 10/15] smc: link layer control (LLC)

Ursula Braun
2016-09-27T16:41:51Z

send and receive LLC messages CONFIRM_LINK (via IB message send and CQE)

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
---
net/smc/Makefile | 2 +-
net/smc/af_smc.c | 94 ++++++++++++++++++++++++++++++-
net/smc/smc_clc.h | 2 +
net/smc/smc_core.c | 8 +++
net/smc/smc_core.h | 4 ++
net/smc/smc_llc.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++++
net/smc/smc_llc.h | 63 +++++++++++++++++++++
7 files changed, 328 insertions(+), 3 deletions(-)
create mode 100644 net/smc/smc_llc.c
create mode 100644 net/smc/smc_llc.h

diff --git a/net/smc/Makefile b/net/smc/Makefile
index b19120e..73320bf 100644
--- a/net/smc/Makefile
+++ b/net/smc/Makefile
@@ -1,2 +1,2 @@
obj-$(CONFIG_SMC) += smc.o
-smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o smc_wr.o
+smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o smc_wr.o smc_llc.o
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 2a7c0df..5cddce0 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -31,6 +31,7 @@

#include "smc.h"
#include "smc_clc.h"
+#include "smc_llc.h"
#include "smc_core.h"
#include "smc_ib.h"
#include "smc_pnet.h"
@@ -252,6 +253,41 @@ out:
return rc;
}

+static int smc_clnt_conf_first_link(struct smc_sock *smc, union ib_gid *gid)
+{
+ struct smc_link_group *lgr = smc->conn.lgr;
+ struct smc_link *link;
+ int rest;
+ int rc;
+
+ link = &lgr->lnk[SMC_SINGLE_LINK];
+ /* receive CONFIRM LINK request from server over RoCE fabric */
+ rest = wait_for_completion_interruptible_timeout(
+ &link->llc_confirm,
+ SMC_LLC_WAIT_FIRST_TIME);
+ if (rest <= 0) {
+ struct smc_clc_msg_decline dclc;
+
+ rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+ SMC_CLC_DECLINE);
+ return rc;
+ }
+
+ rc = smc_ib_modify_qp_rts(link);
+ if (rc)
+ return SMC_CLC_DECL_INTERR;
+
+ smc_wr_remember_qp_attr(link);
+ /* send CONFIRM LINK response over RoCE fabric */
+ rc = smc_llc_send_confirm_link(link,
+ link->smcibdev->mac[link->ibport - 1],
+ gid, SMC_LLC_RESP);
+ if (rc < 0)
+ return SMC_CLC_DECL_TCL;
+
+ return rc;
+}
+
static void smc_conn_save_peer_info(struct smc_sock *smc,
struct smc_clc_msg_accept_confirm *clc)
{
@@ -369,7 +405,17 @@ static int smc_connect_rdma(struct smc_sock *smc)
if (rc)
goto out_err_unlock;

- /* tbd in follow-on patch: llc_confirm */
+ if (local_contact == SMC_FIRST_CONTACT) {
+ /* QP confirmation over RoCE fabric */
+ reason_code = smc_clnt_conf_first_link(
+ smc, &smcibdev->gid[ibport - 1]);
+ if (reason_code < 0) {
+ rc = reason_code;
+ goto out_err_unlock;
+ }
+ if (reason_code > 0)
+ goto decline_rdma_unlock;
+ }

mutex_unlock(&smc_create_lgr_pending);
out_connected:
@@ -554,6 +600,36 @@ static void smc_close_non_accepted(struct sock *sk)
sock_put(sk);
}

+static int smc_serv_conf_first_link(struct smc_sock *smc)
+{
+ struct smc_link_group *lgr = smc->conn.lgr;
+ struct smc_link *link;
+ int rest;
+ int rc;
+
+ link = &lgr->lnk[SMC_SINGLE_LINK];
+ /* send CONFIRM LINK request to client over the RoCE fabric */
+ rc = smc_llc_send_confirm_link(link,
+ link->smcibdev->mac[link->ibport - 1],
+ &link->smcibdev->gid[link->ibport - 1],
+ SMC_LLC_REQ);
+ if (rc < 0)
+ return SMC_CLC_DECL_TCL;
+
+ /* receive CONFIRM LINK response from client over the RoCE fabric */
+ rest = wait_for_completion_interruptible_timeout(
+ &link->llc_confirm_resp,
+ SMC_LLC_WAIT_FIRST_TIME);
+ if (rest <= 0) {
+ struct smc_clc_msg_decline dclc;
+
+ rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+ SMC_CLC_DECLINE);
+ }
+
+ return rc;
+}
+
/* setup for RDMA connection of server */
static void smc_listen_work(struct work_struct *work)
{
@@ -666,13 +742,21 @@ static void smc_listen_work(struct work_struct *work)
goto decline_rdma;
}

- /* tbd in follow-on patch: modify_qp, llc_confirm */
if (local_contact == SMC_FIRST_CONTACT) {
rc = smc_ib_ready_link(link);
if (rc) {
reason_code = SMC_CLC_DECL_INTERR;
goto decline_rdma;
}
+ /* QP confirmation over RoCE fabric */
+ reason_code = smc_serv_conf_first_link(new_smc);
+ if (reason_code < 0) {
+ /* peer is not aware of a problem */
+ rc = reason_code;
+ goto out_err;
+ }
+ if (reason_code > 0)
+ goto decline_rdma;
}

out_connected:
@@ -1122,6 +1206,12 @@ static int __init smc_init(void)
if (rc)
return rc;

+ rc = smc_llc_init();
+ if (rc) {
+ pr_err("%s: smc_llc_init fails with %d\n", __func__, rc);
+ goto out_pnet;
+ }
+
rc = proto_register(&smc_proto, 1);
if (rc) {
pr_err("%s: proto_register fails with %d\n", __func__, rc);
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index ba42f7b..c1821ff 100644
--- a/net/smc/smc_clc.h
+++ b/net/smc/smc_clc.h
@@ -33,6 +33,8 @@ static const char SMC_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xd9'};
#define SMC_CLC_DECL_SYNCERR 0x04000000 /* synchronization error */
#define SMC_CLC_DECL_REPLY 0x06000000 /* reply to a received decline */
#define SMC_CLC_DECL_INTERR 0x99990000 /* internal error */
+#define SMC_CLC_DECL_TCL 0x02040000 /* timeout w4 QP confirm */
+#define SMC_CLC_DECL_SEND 0x07000000 /* sending problem */

struct smc_clc_msg_hdr { /* header1 of clc messages */
u8 eyecatcher[4]; /* eye catcher */
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 9c73604..1202d16 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -21,9 +21,13 @@
#include "smc_core.h"
#include "smc_ib.h"
#include "smc_wr.h"
+#include "smc_llc.h"

+#define SMC_LGR_NUM_INCR 256
#define SMC_LGR_FREE_DELAY (600 * HZ)

+static u32 smc_lgr_num; /* unique link group number */
+
/* Register connection's alert token in our lookup structure.
* To use rbtrees we have to implement our own insert core.
* Requires @conns_lock
@@ -150,6 +154,8 @@ static int smc_lgr_create(struct smc_sock *smc, __be32 peer_in_addr,
INIT_LIST_HEAD(&lgr->sndbufs[i]);
INIT_LIST_HEAD(&lgr->rmbs[i]);
}
+ smc_lgr_num += SMC_LGR_NUM_INCR;
+ lgr->id = smc_lgr_num;
INIT_DELAYED_WORK(&lgr->free_work, smc_lgr_free_work);
lgr->conns_all = RB_ROOT;

@@ -177,6 +183,8 @@ static int smc_lgr_create(struct smc_sock *smc, __be32 peer_in_addr,
rc = smc_wr_create_link(lnk);
if (rc)
goto destroy_qp;
+ init_completion(&lnk->llc_confirm);
+ init_completion(&lnk->llc_confirm_resp);

smc->conn.lgr = lgr;
rwlock_init(&lgr->conns_lock);
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index d2f4ee3..3c3afe7 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -75,6 +75,9 @@ struct smc_link {
u32 peer_psn; /* QP rx initial packet seqno */
u8 peer_mac[ETH_ALEN]; /* = gid[8:10||13:15] */
u8 peer_gid[sizeof(union ib_gid)]; /* gid of peer*/
+ u8 link_id; /* unique # within link group */
+ struct completion llc_confirm; /* wait for rx of conf link */
+ struct completion llc_confirm_resp; /* wait 4 rx of cnf lnk rsp */
};

/* For now we just allow one parallel link per link group. The SMC protocol
@@ -126,6 +129,7 @@ struct smc_link_group {
SMC_RMBS_PER_LGR_MAX)];
/* used rtoken elements */

+ u32 id; /* unique lgr id */
struct delayed_work free_work; /* delayed freeing of an lgr */
};

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
new file mode 100644
index 0000000..7ee2835
--- /dev/null
+++ b/net/smc/smc_llc.c
@@ -0,0 +1,158 @@
+/*
+ * 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"
+
+/********************************** 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 */
+ confllc->link_uid = htonl(lgr->id);
+ 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;
+}
diff --git a/net/smc/smc_llc.h b/net/smc/smc_llc.h
new file mode 100644
index 0000000..57b1b4b
--- /dev/null
+++ b/net/smc/smc_llc.h
@@ -0,0 +1,63 @@
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * Definitions for LLC (link layer control) message handling
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * Author(s): Klaus Wacker <Klaus.Wacker@de.ibm.com>
+ * Ursula Braun <ubraun@linux.vnet.ibm.com>
+ */
+
+#ifndef SMC_LLC_H
+#define SMC_LLC_H
+
+#include "smc_wr.h"
+
+#define SMC_LLC_FLAG_RESP 0x80
+
+#define SMC_LLC_WAIT_FIRST_TIME (5 * HZ)
+
+enum smc_llc_reqresp {
+ SMC_LLC_REQ,
+ SMC_LLC_RESP
+};
+
+enum smc_llc_msg_type {
+ SMC_LLC_CONFIRM_LINK = 0x01,
+};
+
+#define SMC_LLC_DATA_LEN 40
+
+struct smc_llc_hdr {
+ struct smc_wr_rx_hdr common;
+ u8 length; /* 44 */
+ u8 reserved;
+ u8 flags;
+} __packed;
+
+struct smc_llc_msg_confirm_link { /* type 0x01 */
+ struct smc_llc_hdr hd;
+ u8 sender_mac[ETH_ALEN];
+ union ib_gid sender_gid;
+ u8 sender_qp_num[3];
+ u8 link_num;
+ __be32 link_uid;
+ u8 max_links;
+ u8 reserved[9];
+} __packed;
+
+union smc_llc_msg {
+ struct smc_llc_msg_confirm_link confirm_link;
+ struct {
+ struct smc_llc_hdr hdr;
+ u8 data[SMC_LLC_DATA_LEN];
+ } __packed raw;
+} __packed;
+
+/* transmit */
+int smc_llc_send_confirm_link(struct smc_link *, u8 *, union ib_gid *,
+ enum smc_llc_reqresp);
+int smc_llc_init(void) __init;
+
+#endif /* SMC_LLC_H */
--
2.8.4