[linux.git] / net / smc / smc_cdc.c

// 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"

/********************************** send *************************************/

struct smc_cdc_tx_pend {
	struct smc_connection	*conn;		/* socket connection */
	union smc_host_cursor	cursor;	/* tx sndbuf cursor sent */
	union smc_host_cursor	p_cursor;	/* rx RMBE cursor produced */
	u16			ctrl_seq;	/* conn. tx sequence # */
};

/* 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_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,
				     (struct smc_wr_tx_pend_priv **)pend);
	if (!conn->alert_token_local)
		/* 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)
{
	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->local_tx_ctrl, conn);
	rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
	if (!rc)
		smc_curs_copy(&conn->rx_curs_confirmed,
			      &conn->local_tx_ctrl.cons, conn);

	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, &pend);
	if (rc)
		return rc;

	return smc_cdc_msg_send(conn, wr_buf, pend);
}

int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
{
	int rc;

	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);
	/* 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->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_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;

	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();
	}

	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 ||
		    conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
		    conn->local_rx_ctrl.prod_flags.urg_data_pending) {
			if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
				conn->urg_state = SMC_URG_NOTYET;
			/* force immediate tx of current consumer cursor, but
			 * under send_lock to guarantee arrival in seqno-order
			 */
			if (smc->sk.sk_state != SMC_INIT)
				smc_tx_sndbuf_nonempty(conn);
		}
	}

	/* piggy backed tx info */
	/* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
	if (diff_cons && smc_tx_prepared_sends(conn)) {
		smc_tx_sndbuf_nonempty(conn);
		/* trigger socket release if connection closed */
		smc_close_wake_tx_prepared(smc);
	}
	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;
		sock_set_flag(&smc->sk, SOCK_DONE);
		sock_hold(&smc->sk); /* sock_put in close_work */
		if (!schedule_work(&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(unsigned long data)
{
	struct smc_connection *conn = (struct smc_connection *)data;
	struct smcd_cdc_msg *data_cdc;
	struct smcd_cdc_msg cdc;
	struct smc_sock *smc;

	if (!conn)
		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_init(&conn->rx_tsklet, smcd_cdc_rx_tsklet, (unsigned long)conn);
}

/***************************** 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)
		return;
	smc = container_of(conn, struct smc_sock, conn);

	if (!cdc->prod_flags.failover_validation) {
		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;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
5f08318f UB	2	/*
	3	* Shared Memory Communications over RDMA (SMC-R) and RoCE
	4	*
	5	* Connection Data Control (CDC)
	6	* handles flow control
	7	*
	8	* Copyright IBM Corp. 2016
	9	*
	10	* Author(s): Ursula Braun <[email protected]>
	11	*/
	12
	13	#include <linux/spinlock.h>
	14
	15	#include "smc.h"
	16	#include "smc_wr.h"
	17	#include "smc_cdc.h"
e6727f39	18	#include "smc_tx.h"
952310cc	19	#include "smc_rx.h"
b38d7324	20	#include "smc_close.h"
5f08318f UB	21
	22	/******************************** send ***********************************/
	23
	24	struct smc_cdc_tx_pend {
	25	struct smc_connection conn; / socket connection */
	26	union smc_host_cursor cursor; /* tx sndbuf cursor sent */
	27	union smc_host_cursor p_cursor; /* rx RMBE cursor produced */
	28	u16 ctrl_seq; /* conn. tx sequence # */
	29	};
	30
	31	/* handler for send/transmission completion of a CDC msg */
	32	static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
	33	struct smc_link *link,
	34	enum ib_wc_status wc_status)
	35	{
	36	struct smc_cdc_tx_pend cdcpend = (struct smc_cdc_tx_pend )pnd_snd;
bac6de7b	37	struct smc_connection *conn = cdcpend->conn;
5f08318f UB	38	struct smc_sock *smc;
	39	int diff;
	40
bac6de7b	41	if (!conn)
5f08318f UB	42	/* already dismissed */
	43	return;
	44
bac6de7b	45	smc = container_of(conn, struct smc_sock, conn);
5f08318f UB	46	bh_lock_sock(&smc->sk);
5f08318f UB	47	if (!wc_status) {
69cb7dc0	48	diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len,
5f08318f UB	49	&cdcpend->conn->tx_curs_fin,
	50	&cdcpend->cursor);
	51	/* sndbuf_space is decreased in smc_sendmsg */
	52	smp_mb__before_atomic();
	53	atomic_add(diff, &cdcpend->conn->sndbuf_space);
69cb7dc0	54	/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
5f08318f	55	smp_mb__after_atomic();
bac6de7b	56	smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
5f08318f	57	}
e6727f39	58	smc_tx_sndbuf_nonfull(smc);
5f08318f UB	59	bh_unlock_sock(&smc->sk);
	60	}
	61
51957bc5	62	int smc_cdc_get_free_slot(struct smc_connection *conn,
5f08318f UB	63	struct smc_wr_buf **wr_buf,
	64	struct smc_cdc_tx_pend **pend)
	65	{
51957bc5	66	struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
1a0a04c7	67	int rc;
51957bc5	68
1a0a04c7 UB	69	rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
	70	(struct smc_wr_tx_pend_priv **)pend);
	71	if (!conn->alert_token_local)
	72	/* abnormal termination */
	73	rc = -EPIPE;
	74	return rc;
5f08318f UB	75	}
	76
	77	static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
	78	struct smc_cdc_tx_pend *pend)
	79	{
	80	BUILD_BUG_ON_MSG(
	81	sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
	82	"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
	83	BUILD_BUG_ON_MSG(
b9a22dd9	84	offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
5f08318f UB	85	"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()");
	86	BUILD_BUG_ON_MSG(
	87	sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
	88	"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
	89	pend->conn = conn;
	90	pend->cursor = conn->tx_curs_sent;
	91	pend->p_cursor = conn->local_tx_ctrl.prod;
	92	pend->ctrl_seq = conn->tx_cdc_seq;
	93	}
	94
	95	int smc_cdc_msg_send(struct smc_connection *conn,
	96	struct smc_wr_buf *wr_buf,
	97	struct smc_cdc_tx_pend *pend)
	98	{
	99	struct smc_link *link;
	100	int rc;
	101
	102	link = &conn->lgr->lnk[SMC_SINGLE_LINK];
	103
	104	smc_cdc_add_pending_send(conn, pend);
	105
	106	conn->tx_cdc_seq++;
	107	conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
	108	smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf,
	109	&conn->local_tx_ctrl, conn);
	110	rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
	111	if (!rc)
bac6de7b SR	112	smc_curs_copy(&conn->rx_curs_confirmed,
bac6de7b SR	113	&conn->local_tx_ctrl.cons, conn);
5f08318f UB	114
	115	return rc;
	116	}
	117
be244f28	118	static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
5f08318f UB	119	{
	120	struct smc_cdc_tx_pend *pend;
	121	struct smc_wr_buf *wr_buf;
	122	int rc;
	123
51957bc5	124	rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend);
5f08318f UB	125	if (rc)
	126	return rc;
	127
	128	return smc_cdc_msg_send(conn, wr_buf, pend);
	129	}
	130
be244f28 HW	131	int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
	132	{
	133	int rc;
	134
	135	if (conn->lgr->is_smcd) {
	136	spin_lock_bh(&conn->send_lock);
	137	rc = smcd_cdc_msg_send(conn);
	138	spin_unlock_bh(&conn->send_lock);
	139	} else {
	140	rc = smcr_cdc_get_slot_and_msg_send(conn);
	141	}
	142
	143	return rc;
	144	}
	145
5f08318f UB	146	static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
	147	unsigned long data)
	148	{
	149	struct smc_connection conn = (struct smc_connection )data;
	150	struct smc_cdc_tx_pend *cdc_pend =
	151	(struct smc_cdc_tx_pend *)tx_pend;
	152
	153	return cdc_pend->conn == conn;
	154	}
	155
	156	static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
	157	{
	158	struct smc_cdc_tx_pend *cdc_pend =
	159	(struct smc_cdc_tx_pend *)tx_pend;
	160
	161	cdc_pend->conn = NULL;
	162	}
	163
	164	void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
	165	{
	166	struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
	167
	168	smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
	169	smc_cdc_tx_filter, smc_cdc_tx_dismisser,
	170	(unsigned long)conn);
	171	}
	172
be244f28 HW	173	/* Send a SMC-D CDC header.
	174	* This increments the free space available in our send buffer.
	175	* Also update the confirmed receive buffer with what was sent to the peer.
	176	*/
	177	int smcd_cdc_msg_send(struct smc_connection *conn)
	178	{
	179	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
b9a22dd9	180	union smc_host_cursor curs;
be244f28 HW	181	struct smcd_cdc_msg cdc;
	182	int rc, diff;
	183
	184	memset(&cdc, 0, sizeof(cdc));
	185	cdc.common.type = SMC_CDC_MSG_TYPE;
b9a22dd9 UB	186	curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
	187	cdc.prod.wrap = curs.wrap;
	188	cdc.prod.count = curs.count;
	189	curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
	190	cdc.cons.wrap = curs.wrap;
	191	cdc.cons.count = curs.count;
	192	cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
	193	cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
be244f28 HW	194	rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
	195	if (rc)
	196	return rc;
b9a22dd9	197	smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
be244f28 HW	198	/* Calculate transmitted data and increment free send buffer space */
	199	diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
	200	&conn->tx_curs_sent);
	201	/* increased by confirmed number of bytes */
	202	smp_mb__before_atomic();
	203	atomic_add(diff, &conn->sndbuf_space);
	204	/* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
	205	smp_mb__after_atomic();
bac6de7b	206	smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
be244f28 HW	207
	208	smc_tx_sndbuf_nonfull(smc);
	209	return rc;
	210	}
	211
5f08318f UB	212	/******************************* receive *********************************/
	213
	214	static inline bool smc_cdc_before(u16 seq1, u16 seq2)
	215	{
	216	return (s16)(seq1 - seq2) < 0;
	217	}
	218
de8474eb SR	219	static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
	220	int *diff_prod)
	221	{
	222	struct smc_connection *conn = &smc->conn;
	223	char *base;
	224
	225	/* new data included urgent business */
bac6de7b	226	smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
de8474eb SR	227	conn->urg_state = SMC_URG_VALID;
	228	if (!sock_flag(&smc->sk, SOCK_URGINLINE))
	229	/* we'll skip the urgent byte, so don't account for it */
	230	(*diff_prod)--;
be244f28	231	base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
de8474eb SR	232	if (conn->urg_curs.count)
	233	conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
	234	else
	235	conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
	236	sk_send_sigurg(&smc->sk);
	237	}
	238
5f08318f	239	static void smc_cdc_msg_recv_action(struct smc_sock *smc,
5f08318f UB	240	struct smc_cdc_msg *cdc)
	241	{
	242	union smc_host_cursor cons_old, prod_old;
	243	struct smc_connection *conn = &smc->conn;
	244	int diff_cons, diff_prod;
	245
bac6de7b SR	246	smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
bac6de7b SR	247	smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
5f08318f UB	248	smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
	249
	250	diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
	251	&conn->local_rx_ctrl.cons);
	252	if (diff_cons) {
	253	/* peer_rmbe_space is decreased during data transfer with RDMA
	254	* write
	255	*/
	256	smp_mb__before_atomic();
	257	atomic_add(diff_cons, &conn->peer_rmbe_space);
	258	/* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
	259	smp_mb__after_atomic();
	260	}
	261
69cb7dc0	262	diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
5f08318f UB	263	&conn->local_rx_ctrl.prod);
5f08318f UB	264	if (diff_prod) {
de8474eb SR	265	if (conn->local_rx_ctrl.prod_flags.urg_data_present)
de8474eb SR	266	smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
5f08318f UB	267	/* bytes_to_rcv is decreased in smc_recvmsg */
	268	smp_mb__before_atomic();
	269	atomic_add(diff_prod, &conn->bytes_to_rcv);
69cb7dc0	270	/* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
5f08318f	271	smp_mb__after_atomic();
952310cc	272	smc->sk.sk_data_ready(&smc->sk);
de8474eb SR	273	} else {
	274	if (conn->local_rx_ctrl.prod_flags.write_blocked \|\|
	275	conn->local_rx_ctrl.prod_flags.cons_curs_upd_req \|\|
	276	conn->local_rx_ctrl.prod_flags.urg_data_pending) {
	277	if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
	278	conn->urg_state = SMC_URG_NOTYET;
	279	/* force immediate tx of current consumer cursor, but
	280	* under send_lock to guarantee arrival in seqno-order
	281	*/
5607016c UB	282	if (smc->sk.sk_state != SMC_INIT)
5607016c UB	283	smc_tx_sndbuf_nonempty(conn);
de8474eb	284	}
5f08318f UB	285	}
5f08318f UB	286
51f1de79 UB	287	/* piggy backed tx info */
	288	/* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
	289	if (diff_cons && smc_tx_prepared_sends(conn)) {
	290	smc_tx_sndbuf_nonempty(conn);
	291	/* trigger socket release if connection closed */
	292	smc_close_wake_tx_prepared(smc);
	293	}
de8474eb SR	294	if (diff_cons && conn->urg_tx_pend &&
	295	atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
	296	/* urg data confirmed by peer, indicate we're ready for more */
	297	conn->urg_tx_pend = false;
	298	smc->sk.sk_write_space(&smc->sk);
	299	}
51f1de79	300
b38d7324	301	if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
5f08318f	302	smc->sk.sk_err = ECONNRESET;
b38d7324 UB	303	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
b38d7324 UB	304	}
46c28dbd UB	305	if (smc_cdc_rxed_any_close_or_senddone(conn)) {
	306	smc->sk.sk_shutdown \|= RCV_SHUTDOWN;
	307	if (smc->clcsock && smc->clcsock->sk)
	308	smc->clcsock->sk->sk_shutdown \|= RCV_SHUTDOWN;
	309	sock_set_flag(&smc->sk, SOCK_DONE);
51f1de79 UB	310	sock_hold(&smc->sk); /* sock_put in close_work */
	311	if (!schedule_work(&conn->close_work))
	312	sock_put(&smc->sk);
b38d7324	313	}
5f08318f UB	314	}
	315
	316	/* called under tasklet context */
d7b0e37c	317	static void smc_cdc_msg_recv(struct smc_sock smc, struct smc_cdc_msg cdc)
5f08318f	318	{
5f08318f	319	sock_hold(&smc->sk);
5f08318f	320	bh_lock_sock(&smc->sk);
d7b0e37c	321	smc_cdc_msg_recv_action(smc, cdc);
5f08318f UB	322	bh_unlock_sock(&smc->sk);
	323	sock_put(&smc->sk); /* no free sk in softirq-context */
	324	}
	325
be244f28 HW	326	/* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
	327	* handler to indicate update in the DMBE.
	328	*
	329	* Context:
	330	* - tasklet context
	331	*/
	332	static void smcd_cdc_rx_tsklet(unsigned long data)
	333	{
	334	struct smc_connection conn = (struct smc_connection )data;
b9a22dd9	335	struct smcd_cdc_msg *data_cdc;
be244f28 HW	336	struct smcd_cdc_msg cdc;
	337	struct smc_sock *smc;
	338
	339	if (!conn)
	340	return;
	341
b9a22dd9 UB	342	data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
	343	smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
	344	smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
be244f28 HW	345	smc = container_of(conn, struct smc_sock, conn);
	346	smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
	347	}
	348
	349	/* Initialize receive tasklet. Called from ISM device IRQ handler to start
	350	* receiver side.
	351	*/
	352	void smcd_cdc_rx_init(struct smc_connection *conn)
	353	{
	354	tasklet_init(&conn->rx_tsklet, smcd_cdc_rx_tsklet, (unsigned long)conn);
	355	}
	356
5f08318f UB	357	/*************************** init, exit, misc ****************************/
	358
	359	static void smc_cdc_rx_handler(struct ib_wc wc, void buf)
	360	{
	361	struct smc_link link = (struct smc_link )wc->qp->qp_context;
	362	struct smc_cdc_msg *cdc = buf;
d7b0e37c HW	363	struct smc_connection *conn;
	364	struct smc_link_group *lgr;
	365	struct smc_sock *smc;
5f08318f UB	366
	367	if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
	368	return; /* short message */
cbba07a7	369	if (cdc->len != SMC_WR_TX_SIZE)
5f08318f	370	return; /* invalid message */
d7b0e37c HW	371
d7b0e37c HW	372	/* lookup connection */
00e5fb26	373	lgr = smc_get_lgr(link);
d7b0e37c HW	374	read_lock_bh(&lgr->conns_lock);
	375	conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
	376	read_unlock_bh(&lgr->conns_lock);
	377	if (!conn)
	378	return;
	379	smc = container_of(conn, struct smc_sock, conn);
	380
	381	if (!cdc->prod_flags.failover_validation) {
	382	if (smc_cdc_before(ntohs(cdc->seqno),
	383	conn->local_rx_ctrl.seqno))
	384	/* received seqno is old */
	385	return;
	386	}
	387	smc_cdc_msg_recv(smc, cdc);
5f08318f UB	388	}
	389
	390	static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
	391	{
	392	.handler = smc_cdc_rx_handler,
	393	.type = SMC_CDC_MSG_TYPE
	394	},
	395	{
	396	.handler = NULL,
	397	}
	398	};
	399
	400	int __init smc_cdc_init(void)
	401	{
	402	struct smc_wr_rx_handler *handler;
	403	int rc = 0;
	404
	405	for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
	406	INIT_HLIST_NODE(&handler->list);
	407	rc = smc_wr_rx_register_handler(handler);
	408	if (rc)
	409	break;
	410	}
	411	return rc;
	412	}