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// 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 <ubraun@linux.vnet.ibm.com>
*/
#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"
/********************************** 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_sock *smc;
int diff;
if (!conn)
/* already dismissed */
return;
smc = container_of(conn, struct smc_sock, conn);
bh_lock_sock(&smc->sk);
if (!wc_status) {
diff = smc_curs_diff(cdcpend->conn->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_tx_sndbuf_nonfull(smc);
bh_unlock_sock(&smc->sk);
}
int smc_cdc_get_free_slot(struct smc_connection *conn,
struct smc_wr_buf **wr_buf,
struct smc_rdma_wr **wr_rdma_buf,
struct smc_cdc_tx_pend **pend)
{
struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
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 */
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)
{
union smc_host_cursor cfed;
struct smc_link *link;
int rc;
link = &conn->lgr->lnk[SMC_SINGLE_LINK];
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);
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;
}
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;
int rc;
rc = smc_cdc_get_free_slot(conn, &wr_buf, NULL, &pend);
if (rc)
return rc;
spin_lock_bh(&conn->send_lock);
rc = smc_cdc_msg_send(conn, wr_buf, pend);
spin_unlock_bh(&conn->send_lock);
return rc;
}
int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
{
int rc;
if (!conn->lgr || (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;
}
static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
unsigned long data)
{
struct smc_connection *conn = (struct smc_connection *)data;
struct smc_cdc_tx_pend *cdc_pend =
(struct smc_cdc_tx_pend *)tx_pend;
return cdc_pend->conn == conn;
}
static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
{
struct smc_cdc_tx_pend *cdc_pend =
(struct smc_cdc_tx_pend *)tx_pend;
cdc_pend->conn = NULL;
}
void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
{
struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
smc_cdc_tx_filter, smc_cdc_tx_dismisser,
(unsigned long)conn);
}
/* 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;
/* 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 rc;
}
/********************************* 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->
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