// SPDX-License-Identifier: GPL-2.0
/*
* Shared Memory Communications over RDMA (SMC-R) and RoCE
*
* Connection Data Control (CDC)
* handles flow control
*
* Copyright IBM Corp. 2016
*
* Author(s): Ursula Braun <[email protected]>
*/
#include <linux/spinlock.h>
#include "smc.h"
#include "smc_wr.h"
#include "smc_cdc.h"
#include "smc_tx.h"
#include "smc_rx.h"
#include "smc_close.h"
#include "smc_ism.h"
/********************************** send *************************************/
/* handler for send/transmission completion of a CDC msg */
static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
struct smc_link *link,
enum ib_wc_status wc_status)
{
struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;
struct smc_connection *conn = cdcpend->conn;
struct smc_buf_desc *sndbuf_desc;
struct smc_sock *smc;
int diff;
sndbuf_desc = conn->sndbuf_desc;
smc = container_of(conn, struct smc_sock, conn);
bh_lock_sock(&smc->sk);
if (!wc_status && sndbuf_desc) {
diff = smc_curs_diff(sndbuf_desc->len,
&cdcpend->conn->tx_curs_fin,
&cdcpend->cursor);
/* sndbuf_space is decreased in smc_sendmsg */
smp_mb__before_atomic();
atomic_add(diff, &cdcpend->conn->sndbuf_space);
/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
smp_mb__after_atomic();
smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
smc_curs_copy(&conn->local_tx_ctrl_fin, &cdcpend->p_cursor,
conn);
conn->tx_cdc_seq_fin = cdcpend->ctrl_seq;
}
if (atomic_dec_and_test(&conn->cdc_pend_tx_wr)) {
/* If user owns the sock_lock, mark the connection need sending.
* User context will later try to send when it release sock_lock
* in smc_release_cb()
*/
if (sock_owned_by_user(&smc->sk))
conn->tx_in_release_sock = true;
else
smc_tx_pending(conn);
if (unlikely(wq_has_sleeper(&conn->cdc_pend_tx_wq)))
wake_up(&conn->cdc_pend_tx_wq);
}
WARN_ON(atomic_read(&conn->cdc_pend_tx_wr) < 0);
smc_tx_sndbuf_nonfull(smc);
bh_unlock_sock(&smc->sk);
}
int smc_cdc_get_free_slot(struct smc_connection *conn,
struct smc_link *link,
struct smc_wr_buf **wr_buf,
struct smc_rdma_wr **wr_rdma_buf,
struct smc_cdc_tx_pend **pend)
{
int rc;
rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
wr_rdma_buf,
(struct smc_wr_tx_pend_priv **)pend);
if (conn->killed) {
/* abnormal termination */
if (!rc)
smc_wr_tx_put_slot(link,
(struct smc_wr_tx_pend_priv *)(*pend));
rc = -EPIPE;
}
return rc;
}
static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
struct smc_cdc_tx_pend *pend)
{
BUILD_BUG_ON_MSG(
sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
BUILD_BUG_ON_MSG(
offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
"must adapt SMC_WR_TX_SIZE to sizeof(struct smc_cdc_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_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
pend->conn = conn;
pend->cursor = conn->tx_curs_sent;
pend->p_cursor = conn->local_tx_ctrl.prod;
pend->ctrl_seq = conn->tx_cdc_seq;
}
int smc_cdc_msg_send(struct smc_connection *conn,
struct smc_wr_buf *wr_buf,
struct smc_cdc_tx_pend *pend)
{
struct smc_link *link = conn->lnk;
union smc_host_cursor cfed;
int rc;
smc_cdc_add_pending_send(conn, pend);
conn->tx_cdc_seq++;
conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
atomic_inc(&conn->cdc_pend_tx_wr);
smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
if (!rc) {
smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
} else {
conn->tx_cdc_seq--;
conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
atomic_dec(&conn->cdc_pend_tx_wr);
}
return rc;
}
/* send a validation msg indicating the move of a conn to an other QP link */
int smcr_cdc_msg_send_validation(struct smc_connection *conn,
struct smc_cdc_tx_pend *pend,
struct smc_wr_buf *wr_buf)
{
struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
struct smc_link *link = conn->lnk;
struct smc_cdc_msg *peer;
int rc;
peer = (struct smc_cdc_msg *)wr_buf;
peer->common.type = local->common.type;
peer->len = local->len;
peer->seqno = htons(conn->tx_cdc_seq_fin); /* seqno last compl. tx */
peer->token = htonl(local->token);
peer->prod_flags.failover_validation = 1;
/* We need to set pend->conn here to make sure smc_cdc_tx_handler()
* can handle properly
*/
smc_cdc_add_pending_send(conn, pend);
atomic_inc(&conn->cdc_pend_tx_wr);
smp_mb__after_atomic(); /* Make sure cdc_pend_tx_wr added before post */
rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
if (unlikely(rc))
atomic_dec(&conn->cdc_pend_tx_wr);
return rc;
}
static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
{
struct smc_cdc_tx_pend *pend;
struct smc_wr_buf *wr_buf;
struct smc_link *link;
bool again = false;
int rc;
again:
link = conn->lnk;
if (!smc_wr_tx_link_hold(link))
return -ENOLINK;
rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend);
if (rc)
goto put_out;
spin_lock_bh(&conn->send_lock);
if (link != conn->lnk) {
/* link of connection changed, try again one time*/
spin_unlock_bh(&conn->send_lock);
smc_wr_tx_put_slot(link,
(struct smc_wr_tx_pend_priv *)pend);
smc_wr_tx_link_put(link);
if (again)
return -ENOLINK;
again = true;
goto again;
}
rc = smc_cdc_msg_send(conn, wr_buf, pend);
spin_unlock_bh(&conn->send_lock);
put_out:
smc_wr_tx_link_put(link);
return rc;
}
int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
{
int rc;
if (!smc_conn_lgr_valid(conn) ||
(conn->lgr->is_smcd && conn->lgr->peer_shutdown))
return -EPIPE;
if (conn->lgr->is_smcd) {
spin_lock_bh(&conn->send_lock);
rc = smcd_cdc_msg_send(conn);
spin_unlock_bh(&conn->send_lock);
} else {
rc = smcr_cdc_get_slot_and_msg_send(conn);
}
return rc;
}
void smc_cdc_wait_pend_tx_wr(struct smc_connection *conn)
{
wait_event(conn->cdc_pend_tx_wq, !atomic_read(&conn->cdc_pend_tx_wr));
}
/* Send a SMC-D CDC header.
* This increments the free space available in our send buffer.
* Also update the confirmed receive buffer with what was sent to the peer.
*/
int smcd_cdc_msg_send(struct smc_connection *conn)
{
struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
union smc_host_cursor curs;
struct smcd_cdc_msg cdc;
int rc, diff;
memset(&cdc, 0, sizeof(cdc));
cdc.common.type = SMC_CDC_MSG_TYPE;
curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
cdc.prod.wrap = curs.wrap;
cdc.prod.count = curs.count;
curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
cdc.cons.wrap = curs.wrap;
cdc.cons.count = curs.count;
cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
if (rc)
return rc;
smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
if (smc_ism_support_dmb_nocopy(conn->lgr->smcd))
/* if local sndbuf shares the same memory region with
* peer DMB, then don't update the tx_curs_fin
* and sndbuf_space until peer has consumed the data.
*/
return 0;
/* Calculate transmitted data and increment free send buffer space */
diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
&conn->tx_curs_sent);
/* increased by confirmed number of bytes */
smp_mb__before_atomic();
atomic_add(diff, &conn->sndbuf_space);
/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
smp_mb__after_atomic();
smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
smc_tx_sndbuf_nonfull(smc);
return 0;
}
/********************************* receive ***********************************/
static inline bool smc_cdc_before(u16 seq1, u16 seq2)
{
return (s16)(seq1 - seq2) < 0;
}
static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
int *diff_prod)
{
struct smc_connection *conn = &smc->conn;
char *base;
/* new data included urgent business */
smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
conn->urg_state = SMC_URG_VALID;
if (!sock_flag(&smc->sk, SOCK_URGINLINE))
/* we'll skip the urgent byte, so don't account for it */
(*diff_prod)--;
base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
if (conn->urg_curs.count)
conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
else
conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
sk_send_sigurg(&smc->sk);
}
static void smc_cdc_msg_validate(struct smc_sock *smc, struct smc_cdc_msg *cdc,
struct smc_link *link)
{
struct smc_connection *conn = &smc->conn;
u16 recv_seq = ntohs(cdc->seqno);
s16 diff;
/* check that seqnum was seen before */
diff = conn->local_rx_ctrl.seqno - recv_seq;
if (diff < 0) { /* diff larger than 0x7fff */
/* drop connection */
conn->out_of_sync = 1; /* prevent any further receives */
spin_lock_bh(&conn->send_lock);
conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
conn->lnk = link;
spin_unlock_bh(&conn->send_lock);
sock_hold(&smc->sk); /* sock_put in abort_work */
if (!queue_work(smc_close_wq, &conn->abort_work))
sock_put(&smc->sk);
}
}
static void smc_cdc_msg_recv_action(struct smc_sock *smc,
struct smc_cdc_msg *cdc)
{
union smc_host_cursor cons_old, prod_old;
struct smc_connection *conn = &smc->conn;
int diff_cons, diff_prod, diff_tx;
smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
&conn->local_rx_ctrl.cons);
if (diff_cons) {
/* peer_rmbe_space is decreased during data transfer with RDMA
* write
*/
smp_mb__before_atomic();
atomic_add(diff_cons, &conn->peer_rmbe_space);
/* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
smp_mb__after_atomic();
/* if local sndbuf shares the same memory region with
* peer RMB, then update tx_curs_fin and sndbuf_space
* here since peer has already consumed the data.
*/
if (conn->lgr->is_smcd &&
smc_ism_support_dmb_nocopy(conn->lgr->smcd)) {
/* Calculate consumed data and
* increment free send buffer space.
*/
diff_tx = smc_curs_diff(conn->sndbuf_desc->len,
&conn->tx_curs_fin,
&conn->local_rx_ctrl.cons);
/* increase local sndbuf space and fin_curs */
smp_mb__before_atomic();
atomic_add(diff_tx, &conn->sndbuf_space);
/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
smp_mb__after_atomic();
smc_curs_copy(&conn->tx_curs_fin,
&conn->local_rx_ctrl.cons, conn);
smc_tx_sndbuf_nonfull(smc);
}
}
diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
&conn->local_rx_ctrl.prod);
if (diff_prod) {
if (conn->local_rx_ctrl.prod_flags.urg_data_present)
smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
/* bytes_to_rcv is decreased in smc_recvmsg */
smp_mb__before_atomic();
atomic_add(diff_prod, &conn->bytes_to_rcv);
/* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
smp_mb__after_atomic();
smc->sk.sk_data_ready(&smc->sk);
} else {
if (conn->local_rx_ctrl.prod_flags.write_blocked)
smc->sk.sk_data_ready(&smc->sk);
if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
conn->urg_state = SMC_URG_NOTYET;
}
/* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
if ((diff_cons && smc_tx_prepared_sends(conn)) ||
conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
conn->local_rx_ctrl.prod_flags.urg_data_pending) {
if (!sock_owned_by_user(&smc->sk))
smc_tx_pending(conn);
else
conn->tx_in_release_sock = true;
}
if (diff_cons && conn->urg_tx_pend &&
atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
/* urg data confirmed by peer, indicate we're ready for more */
conn->urg_tx_pend = false;
smc->sk.sk_write_space(&smc->sk);
}
if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
smc->sk.sk_err = ECONNRESET;
conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
}
if (smc_cdc_rxed_any_close_or_senddone(conn)) {
smc->sk.sk_shutdown |= RCV_SHUTDOWN;
if (smc->clcsock && smc->clcsock->sk)
smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
smc_sock_set_flag(&smc->sk, SOCK_DONE);
sock_hold(&smc->sk); /* sock_put in close_work */
if (!queue_work(smc_close_wq, &conn->close_work))
sock_put(&smc->sk);
}
}
/* called under tasklet context */
static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
{
sock_hold(&smc->sk);
bh_lock_sock(&smc->sk);
smc_cdc_msg_recv_action(smc, cdc);
bh_unlock_sock(&smc->sk);
sock_put(&smc->sk); /* no free sk in softirq-context */
}
/* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
* handler to indicate update in the DMBE.
*
* Context:
* - tasklet context
*/
static void smcd_cdc_rx_tsklet(struct tasklet_struct *t)
{
struct smc_connection *conn = from_tasklet(conn, t, rx_tsklet);
struct smcd_cdc_msg *data_cdc;
struct smcd_cdc_msg cdc;
struct smc_sock *smc;
if (!conn || conn->killed)
return;
data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
smc = container_of(conn, struct smc_sock, conn);
smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
}
/* Initialize receive tasklet. Called from ISM device IRQ handler to start
* receiver side.
*/
void smcd_cdc_rx_init(struct smc_connection *conn)
{
tasklet_setup(&conn->rx_tsklet, smcd_cdc_rx_tsklet);
}
/***************************** init, exit, misc ******************************/
static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
{
struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
struct smc_cdc_msg *cdc = buf;
struct smc_connection *conn;
struct smc_link_group *lgr;
struct smc_sock *smc;
if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
return; /* short message */
if (cdc->len != SMC_WR_TX_SIZE)
return; /* invalid message */
/* lookup connection */
lgr = smc_get_lgr(link);
read_lock_bh(&lgr->conns_lock);
conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
read_unlock_bh(&lgr->conns_lock);
if (!conn || conn->out_of_sync)
return;
smc = container_of(conn, struct smc_sock, conn);
if (cdc->prod_flags.failover_validation) {
smc_cdc_msg_validate(smc, cdc, link);
return;
}
if (smc_cdc_before(ntohs(cdc->seqno),
conn->local_rx_ctrl.seqno))
/* received seqno is old */
return;
smc_cdc_msg_recv(smc, cdc);
}
static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
{
.handler = smc_cdc_rx_handler,
.type = SMC_CDC_MSG_TYPE
},
{
.handler = NULL,
}
};
int __init smc_cdc_init(void)
{
struct smc_wr_rx_handler *handler;
int rc = 0;
for (handler = smc_cdc_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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