[linux-2.6-block.git] / net / smc / smc_tx.c

/*
 * Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 * Manage send buffer.
 * Producer:
 * Copy user space data into send buffer, if send buffer space available.
 * Consumer:
 * Trigger RDMA write into RMBE of peer and send CDC, if RMBE space available.
 *
 * Copyright IBM Corp. 2016
 *
 * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#include <linux/net.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <linux/sched/signal.h>

#include <net/sock.h>

#include "smc.h"
#include "smc_wr.h"
#include "smc_cdc.h"
#include "smc_tx.h"

/***************************** sndbuf producer *******************************/

/* callback implementation for sk.sk_write_space()
 * to wakeup sndbuf producers that blocked with smc_tx_wait_memory().
 * called under sk_socket lock.
 */
static void smc_tx_write_space(struct sock *sk)
{
	struct socket *sock = sk->sk_socket;
	struct smc_sock *smc = smc_sk(sk);
	struct socket_wq *wq;

	/* similar to sk_stream_write_space */
	if (atomic_read(&smc->conn.sndbuf_space) && sock) {
		clear_bit(SOCK_NOSPACE, &sock->flags);
		rcu_read_lock();
		wq = rcu_dereference(sk->sk_wq);
		if (skwq_has_sleeper(wq))
			wake_up_interruptible_poll(&wq->wait,
						   POLLOUT | POLLWRNORM |
						   POLLWRBAND);
		if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
			sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
		rcu_read_unlock();
	}
}

/* Wakeup sndbuf producers that blocked with smc_tx_wait_memory().
 * Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space().
 */
void smc_tx_sndbuf_nonfull(struct smc_sock *smc)
{
	if (smc->sk.sk_socket &&
	    test_bit(SOCK_NOSPACE, &smc->sk.sk_socket->flags))
		smc->sk.sk_write_space(&smc->sk);
}

/* blocks sndbuf producer until at least one byte of free space available */
static int smc_tx_wait_memory(struct smc_sock *smc, int flags)
{
	DEFINE_WAIT_FUNC(wait, woken_wake_function);
	struct smc_connection *conn = &smc->conn;
	struct sock *sk = &smc->sk;
	bool noblock;
	long timeo;
	int rc = 0;

	/* similar to sk_stream_wait_memory */
	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
	noblock = timeo ? false : true;
	add_wait_queue(sk_sleep(sk), &wait);
	while (1) {
		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
		if (sk->sk_err ||
		    (sk->sk_shutdown & SEND_SHUTDOWN) ||
		    conn->local_tx_ctrl.conn_state_flags.peer_done_writing) {
			rc = -EPIPE;
			break;
		}
		if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
			rc = -ECONNRESET;
			break;
		}
		if (!timeo) {
			if (noblock)
				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
			rc = -EAGAIN;
			break;
		}
		if (signal_pending(current)) {
			rc = sock_intr_errno(timeo);
			break;
		}
		sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
		if (atomic_read(&conn->sndbuf_space))
			break; /* at least 1 byte of free space available */
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
		sk->sk_write_pending++;
		sk_wait_event(sk, &timeo,
			      sk->sk_err ||
			      (sk->sk_shutdown & SEND_SHUTDOWN) ||
			      smc_cdc_rxed_any_close_or_senddone(conn) ||
			      atomic_read(&conn->sndbuf_space),
			      &wait);
		sk->sk_write_pending--;
	}
	remove_wait_queue(sk_sleep(sk), &wait);
	return rc;
}

/* sndbuf producer: main API called by socket layer.
 * called under sock lock.
 */
int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
{
	size_t copylen, send_done = 0, send_remaining = len;
	size_t chunk_len, chunk_off, chunk_len_sum;
	struct smc_connection *conn = &smc->conn;
	union smc_host_cursor prep;
	struct sock *sk = &smc->sk;
	char *sndbuf_base;
	int tx_cnt_prep;
	int writespace;
	int rc, chunk;

	/* This should be in poll */
	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);

	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) {
		rc = -EPIPE;
		goto out_err;
	}

	while (msg_data_left(msg)) {
		if (sk->sk_state == SMC_INIT)
			return -ENOTCONN;
		if (smc->sk.sk_shutdown & SEND_SHUTDOWN ||
		    (smc->sk.sk_err == ECONNABORTED) ||
		    conn->local_tx_ctrl.conn_state_flags.peer_conn_abort)
			return -EPIPE;
		if (smc_cdc_rxed_any_close(conn))
			return send_done ?: -ECONNRESET;

		if (!atomic_read(&conn->sndbuf_space)) {
			rc = smc_tx_wait_memory(smc, msg->msg_flags);
			if (rc) {
				if (send_done)
					return send_done;
				goto out_err;
			}
			continue;
		}

		/* initialize variables for 1st iteration of subsequent loop */
		/* could be just 1 byte, even after smc_tx_wait_memory above */
		writespace = atomic_read(&conn->sndbuf_space);
		/* not more than what user space asked for */
		copylen = min_t(size_t, send_remaining, writespace);
		/* determine start of sndbuf */
		sndbuf_base = conn->sndbuf_desc->cpu_addr;
		smc_curs_write(&prep,
			       smc_curs_read(&conn->tx_curs_prep, conn),
			       conn);
		tx_cnt_prep = prep.count;
		/* determine chunks where to write into sndbuf */
		/* either unwrapped case, or 1st chunk of wrapped case */
		chunk_len = min_t(size_t,
				  copylen, conn->sndbuf_size - tx_cnt_prep);
		chunk_len_sum = chunk_len;
		chunk_off = tx_cnt_prep;
		for (chunk = 0; chunk < 2; chunk++) {
			rc = memcpy_from_msg(sndbuf_base + chunk_off,
					     msg, chunk_len);
			if (rc) {
				if (send_done)
					return send_done;
				goto out_err;
			}
			send_done += chunk_len;
			send_remaining -= chunk_len;

			if (chunk_len_sum == copylen)
				break; /* either on 1st or 2nd iteration */
			/* prepare next (== 2nd) iteration */
			chunk_len = copylen - chunk_len; /* remainder */
			chunk_len_sum += chunk_len;
			chunk_off = 0; /* modulo offset in send ring buffer */
		}
		/* update cursors */
		smc_curs_add(conn->sndbuf_size, &prep, copylen);
		smc_curs_write(&conn->tx_curs_prep,
			       smc_curs_read(&prep, conn),
			       conn);
		/* increased in send tasklet smc_cdc_tx_handler() */
		smp_mb__before_atomic();
		atomic_sub(copylen, &conn->sndbuf_space);
		/* guarantee 0 <= sndbuf_space <= sndbuf_size */
		smp_mb__after_atomic();
		/* since we just produced more new data into sndbuf,
		 * trigger sndbuf consumer: RDMA write into peer RMBE and CDC
		 */
		smc_tx_sndbuf_nonempty(conn);
	} /* while (msg_data_left(msg)) */

	return send_done;

out_err:
	rc = sk_stream_error(sk, msg->msg_flags, rc);
	/* make sure we wake any epoll edge trigger waiter */
	if (unlikely(rc == -EAGAIN))
		sk->sk_write_space(sk);
	return rc;
}

/***************************** sndbuf consumer *******************************/

/* sndbuf consumer: actual data transfer of one target chunk with RDMA write */
static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset,
			     int num_sges, struct ib_sge sges[])
{
	struct smc_link_group *lgr = conn->lgr;
	struct ib_send_wr *failed_wr = NULL;
	struct ib_rdma_wr rdma_wr;
	struct smc_link *link;
	int rc;

	memset(&rdma_wr, 0, sizeof(rdma_wr));
	link = &lgr->lnk[SMC_SINGLE_LINK];
	rdma_wr.wr.wr_id = smc_wr_tx_get_next_wr_id(link);
	rdma_wr.wr.sg_list = sges;
	rdma_wr.wr.num_sge = num_sges;
	rdma_wr.wr.opcode = IB_WR_RDMA_WRITE;
	rdma_wr.remote_addr =
		lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].dma_addr +
		/* RMBE within RMB */
		((conn->peer_conn_idx - 1) * conn->peer_rmbe_size) +
		/* offset within RMBE */
		peer_rmbe_offset;
	rdma_wr.rkey = lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].rkey;
	rc = ib_post_send(link->roce_qp, &rdma_wr.wr, &failed_wr);
	if (rc)
		conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
	return rc;
}

/* sndbuf consumer */
static inline void smc_tx_advance_cursors(struct smc_connection *conn,
					  union smc_host_cursor *prod,
					  union smc_host_cursor *sent,
					  size_t len)
{
	smc_curs_add(conn->peer_rmbe_size, prod, len);
	/* increased in recv tasklet smc_cdc_msg_rcv() */
	smp_mb__before_atomic();
	/* data in flight reduces usable snd_wnd */
	atomic_sub(len, &conn->peer_rmbe_space);
	/* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
	smp_mb__after_atomic();
	smc_curs_add(conn->sndbuf_size, sent, len);
}

/* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit;
 * usable snd_wnd as max transmit
 */
static int smc_tx_rdma_writes(struct smc_connection *conn)
{
	size_t src_off, src_len, dst_off, dst_len; /* current chunk values */
	size_t len, dst_len_sum, src_len_sum, dstchunk, srcchunk;
	union smc_host_cursor sent, prep, prod, cons;
	struct ib_sge sges[SMC_IB_MAX_SEND_SGE];
	struct smc_link_group *lgr = conn->lgr;
	int to_send, rmbespace;
	struct smc_link *link;
	int num_sges;
	int rc;

	/* source: sndbuf */
	smc_curs_write(&sent, smc_curs_read(&conn->tx_curs_sent, conn), conn);
	smc_curs_write(&prep, smc_curs_read(&conn->tx_curs_prep, conn), conn);
	/* cf. wmem_alloc - (snd_max - snd_una) */
	to_send = smc_curs_diff(conn->sndbuf_size, &sent, &prep);
	if (to_send <= 0)
		return 0;

	/* destination: RMBE */
	/* cf. snd_wnd */
	rmbespace = atomic_read(&conn->peer_rmbe_space);
	if (rmbespace <= 0)
		return 0;
	smc_curs_write(&prod,
		       smc_curs_read(&conn->local_tx_ctrl.prod, conn),
		       conn);
	smc_curs_write(&cons,
		       smc_curs_read(&conn->local_rx_ctrl.cons, conn),
		       conn);

	/* if usable snd_wnd closes ask peer to advertise once it opens again */
	conn->local_tx_ctrl.prod_flags.write_blocked = (to_send >= rmbespace);
	/* cf. usable snd_wnd */
	len = min(to_send, rmbespace);

	/* initialize variables for first iteration of subsequent nested loop */
	link = &lgr->lnk[SMC_SINGLE_LINK];
	dst_off = prod.count;
	if (prod.wrap == cons.wrap) {
		/* the filled destination area is unwrapped,
		 * hence the available free destination space is wrapped
		 * and we need 2 destination chunks of sum len; start with 1st
		 * which is limited by what's available in sndbuf
		 */
		dst_len = min_t(size_t,
				conn->peer_rmbe_size - prod.count, len);
	} else {
		/* the filled destination area is wrapped,
		 * hence the available free destination space is unwrapped
		 * and we need a single destination chunk of entire len
		 */
		dst_len = len;
	}
	dst_len_sum = dst_len;
	src_off = sent.count;
	/* dst_len determines the maximum src_len */
	if (sent.count + dst_len <= conn->sndbuf_size) {
		/* unwrapped src case: single chunk of entire dst_len */
		src_len = dst_len;
	} else {
		/* wrapped src case: 2 chunks of sum dst_len; start with 1st: */
		src_len = conn->sndbuf_size - sent.count;
	}
	src_len_sum = src_len;
	for (dstchunk = 0; dstchunk < 2; dstchunk++) {
		num_sges = 0;
		for (srcchunk = 0; srcchunk < 2; srcchunk++) {
			sges[srcchunk].addr =
				conn->sndbuf_desc->dma_addr[SMC_SINGLE_LINK] +
				src_off;
			sges[srcchunk].length = src_len;
			sges[srcchunk].lkey = link->roce_pd->local_dma_lkey;
			num_sges++;
			src_off += src_len;
			if (src_off >= conn->sndbuf_size)
				src_off -= conn->sndbuf_size;
						/* modulo in send ring */
			if (src_len_sum == dst_len)
				break; /* either on 1st or 2nd iteration */
			/* prepare next (== 2nd) iteration */
			src_len = dst_len - src_len; /* remainder */
			src_len_sum += src_len;
		}
		rc = smc_tx_rdma_write(conn, dst_off, num_sges, sges);
		if (rc)
			return rc;
		if (dst_len_sum == len)
			break; /* either on 1st or 2nd iteration */
		/* prepare next (== 2nd) iteration */
		dst_off = 0; /* modulo offset in RMBE ring buffer */
		dst_len = len - dst_len; /* remainder */
		dst_len_sum += dst_len;
		src_len = min_t(int,
				dst_len, conn->sndbuf_size - sent.count);
		src_len_sum = src_len;
	}

	smc_tx_advance_cursors(conn, &prod, &sent, len);
	/* update connection's cursors with advanced local cursors */
	smc_curs_write(&conn->local_tx_ctrl.prod,
		       smc_curs_read(&prod, conn),
		       conn);
							/* dst: peer RMBE */
	smc_curs_write(&conn->tx_curs_sent,
		       smc_curs_read(&sent, conn),
		       conn);
							/* src: local sndbuf */

	return 0;
}

/* Wakeup sndbuf consumers from any context (IRQ or process)
 * since there is more data to transmit; usable snd_wnd as max transmit
 */
int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
{
	struct smc_cdc_tx_pend *pend;
	struct smc_wr_buf *wr_buf;
	int rc;

	spin_lock_bh(&conn->send_lock);
	rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf,
				   &pend);
	if (rc < 0) {
		if (rc == -EBUSY) {
			struct smc_sock *smc =
				container_of(conn, struct smc_sock, conn);

			if (smc->sk.sk_err == ECONNABORTED) {
				rc = sock_error(&smc->sk);
				goto out_unlock;
			}
			rc = 0;
			schedule_work(&conn->tx_work);
		}
		goto out_unlock;
	}

	rc = smc_tx_rdma_writes(conn);
	if (rc) {
		smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK],
				   (struct smc_wr_tx_pend_priv *)pend);
		goto out_unlock;
	}

	rc = smc_cdc_msg_send(conn, wr_buf, pend);

out_unlock:
	spin_unlock_bh(&conn->send_lock);
	return rc;
}

/* Wakeup sndbuf consumers from process context
 * since there is more data to transmit
 */
static void smc_tx_work(struct work_struct *work)
{
	struct smc_connection *conn = container_of(work,
						   struct smc_connection,
						   tx_work);
	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
	int rc;

	lock_sock(&smc->sk);
	rc = smc_tx_sndbuf_nonempty(conn);
	if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked &&
	    !atomic_read(&conn->bytes_to_rcv))
		conn->local_rx_ctrl.prod_flags.write_blocked = 0;
	release_sock(&smc->sk);
}

void smc_tx_consumer_update(struct smc_connection *conn)
{
	union smc_host_cursor cfed, cons;
	struct smc_cdc_tx_pend *pend;
	struct smc_wr_buf *wr_buf;
	int to_confirm, rc;

	smc_curs_write(&cons,
		       smc_curs_read(&conn->local_tx_ctrl.cons, conn),
		       conn);
	smc_curs_write(&cfed,
		       smc_curs_read(&conn->rx_curs_confirmed, conn),
		       conn);
	to_confirm = smc_curs_diff(conn->rmbe_size, &cfed, &cons);

	if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
	    ((to_confirm > conn->rmbe_update_limit) &&
	     ((to_confirm > (conn->rmbe_size / 2)) ||
	      conn->local_rx_ctrl.prod_flags.write_blocked))) {
		rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK],
					   &wr_buf, &pend);
		if (!rc)
			rc = smc_cdc_msg_send(conn, wr_buf, pend);
		if (rc < 0) {
			schedule_work(&conn->tx_work);
			return;
		}
		smc_curs_write(&conn->rx_curs_confirmed,
			       smc_curs_read(&conn->local_tx_ctrl.cons, conn),
			       conn);
		conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
	}
	if (conn->local_rx_ctrl.prod_flags.write_blocked &&
	    !atomic_read(&conn->bytes_to_rcv))
		conn->local_rx_ctrl.prod_flags.write_blocked = 0;
}

/***************************** send initialize *******************************/

/* Initialize send properties on connection establishment. NB: not __init! */
void smc_tx_init(struct smc_sock *smc)
{
	smc->sk.sk_write_space = smc_tx_write_space;
	INIT_WORK(&smc->conn.tx_work, smc_tx_work);
	spin_lock_init(&smc->conn.send_lock);
}
Commit	Line	Data
e6727f39 UB	1	/*
	2	* Shared Memory Communications over RDMA (SMC-R) and RoCE
	3	*
	4	* Manage send buffer.
	5	* Producer:
	6	* Copy user space data into send buffer, if send buffer space available.
	7	* Consumer:
	8	* Trigger RDMA write into RMBE of peer and send CDC, if RMBE space available.
	9	*
	10	* Copyright IBM Corp. 2016
	11	*
	12	* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
	13	*/
	14
	15	#include <linux/net.h>
	16	#include <linux/rcupdate.h>
	17	#include <linux/workqueue.h>
c3edc401 IM	18	#include <linux/sched/signal.h>
c3edc401 IM	19
e6727f39 UB	20	#include <net/sock.h>
	21
	22	#include "smc.h"
	23	#include "smc_wr.h"
	24	#include "smc_cdc.h"
	25	#include "smc_tx.h"
	26
	27	/*************************** sndbuf producer *****************************/
	28
	29	/* callback implementation for sk.sk_write_space()
	30	* to wakeup sndbuf producers that blocked with smc_tx_wait_memory().
	31	* called under sk_socket lock.
	32	*/
	33	static void smc_tx_write_space(struct sock *sk)
	34	{
	35	struct socket *sock = sk->sk_socket;
	36	struct smc_sock *smc = smc_sk(sk);
	37	struct socket_wq *wq;
	38
	39	/* similar to sk_stream_write_space */
	40	if (atomic_read(&smc->conn.sndbuf_space) && sock) {
	41	clear_bit(SOCK_NOSPACE, &sock->flags);
	42	rcu_read_lock();
	43	wq = rcu_dereference(sk->sk_wq);
	44	if (skwq_has_sleeper(wq))
	45	wake_up_interruptible_poll(&wq->wait,
	46	POLLOUT \| POLLWRNORM \|
	47	POLLWRBAND);
	48	if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
	49	sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
	50	rcu_read_unlock();
	51	}
	52	}
	53
	54	/* Wakeup sndbuf producers that blocked with smc_tx_wait_memory().
	55	* Cf. tcp_data_snd_check()=>tcp_check_space()=>tcp_new_space().
	56	*/
	57	void smc_tx_sndbuf_nonfull(struct smc_sock *smc)
	58	{
	59	if (smc->sk.sk_socket &&
	60	test_bit(SOCK_NOSPACE, &smc->sk.sk_socket->flags))
	61	smc->sk.sk_write_space(&smc->sk);
	62	}
	63
	64	/* blocks sndbuf producer until at least one byte of free space available */
	65	static int smc_tx_wait_memory(struct smc_sock *smc, int flags)
	66	{
	67	DEFINE_WAIT_FUNC(wait, woken_wake_function);
	68	struct smc_connection *conn = &smc->conn;
	69	struct sock *sk = &smc->sk;
	70	bool noblock;
	71	long timeo;
	72	int rc = 0;
	73
	74	/* similar to sk_stream_wait_memory */
	75	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
	76	noblock = timeo ? false : true;
	77	add_wait_queue(sk_sleep(sk), &wait);
	78	while (1) {
	79	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
	80	if (sk->sk_err \|\|
	81	(sk->sk_shutdown & SEND_SHUTDOWN) \|\|
	82	conn->local_tx_ctrl.conn_state_flags.peer_done_writing) {
	83	rc = -EPIPE;
84	break;
85	}
86	if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
87	rc = -ECONNRESET;
88	break;
89	}
90	if (!timeo) {
91	if (noblock)
92	set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
93	rc = -EAGAIN;
94	break;
95	}
96	if (signal_pending(current)) {
97	rc = sock_intr_errno(timeo);
98	break;
99	}
100	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
101	if (atomic_read(&conn->sndbuf_space))
102	break; /* at least 1 byte of free space available */
103	set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
104	sk->sk_write_pending++;
105	sk_wait_event(sk, &timeo,
106	sk->sk_err \|\|
107	(sk->sk_shutdown & SEND_SHUTDOWN) \|\|
108	smc_cdc_rxed_any_close_or_senddone(conn) \|\|
109	atomic_read(&conn->sndbuf_space),
110	&wait);
111	sk->sk_write_pending--;
112	}
113	remove_wait_queue(sk_sleep(sk), &wait);
114	return rc;
115	}
116
117	/* sndbuf producer: main API called by socket layer.
118	* called under sock lock.
119	*/
120	int smc_tx_sendmsg(struct smc_sock smc, struct msghdr msg, size_t len)
121	{
122	size_t copylen, send_done = 0, send_remaining = len;
123	size_t chunk_len, chunk_off, chunk_len_sum;
124	struct smc_connection *conn = &smc->conn;
125	union smc_host_cursor prep;
126	struct sock *sk = &smc->sk;
127	char *sndbuf_base;
128	int tx_cnt_prep;
129	int writespace;
130	int rc, chunk;
131
132	/* This should be in poll */
133	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
134
135	if (sk->sk_err \|\| (sk->sk_shutdown & SEND_SHUTDOWN)) {
136	rc = -EPIPE;
137	goto out_err;
138	}
139
140	while (msg_data_left(msg)) {
141	if (sk->sk_state == SMC_INIT)
142	return -ENOTCONN;
143	if (smc->sk.sk_shutdown & SEND_SHUTDOWN \|\|
b38d7324	144	(smc->sk.sk_err == ECONNABORTED) \|\|
e6727f39 UB	145	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort)
	146	return -EPIPE;
	147	if (smc_cdc_rxed_any_close(conn))
	148	return send_done ?: -ECONNRESET;
	149
	150	if (!atomic_read(&conn->sndbuf_space)) {
	151	rc = smc_tx_wait_memory(smc, msg->msg_flags);
	152	if (rc) {
	153	if (send_done)
	154	return send_done;
	155	goto out_err;
	156	}
	157	continue;
	158	}
	159
	160	/* initialize variables for 1st iteration of subsequent loop */
	161	/* could be just 1 byte, even after smc_tx_wait_memory above */
	162	writespace = atomic_read(&conn->sndbuf_space);
	163	/* not more than what user space asked for */
	164	copylen = min_t(size_t, send_remaining, writespace);
	165	/* determine start of sndbuf */
	166	sndbuf_base = conn->sndbuf_desc->cpu_addr;
	167	smc_curs_write(&prep,
	168	smc_curs_read(&conn->tx_curs_prep, conn),
	169	conn);
	170	tx_cnt_prep = prep.count;
	171	/* determine chunks where to write into sndbuf */
	172	/* either unwrapped case, or 1st chunk of wrapped case */
	173	chunk_len = min_t(size_t,
	174	copylen, conn->sndbuf_size - tx_cnt_prep);
	175	chunk_len_sum = chunk_len;
	176	chunk_off = tx_cnt_prep;
	177	for (chunk = 0; chunk < 2; chunk++) {
	178	rc = memcpy_from_msg(sndbuf_base + chunk_off,
	179	msg, chunk_len);
	180	if (rc) {
	181	if (send_done)
	182	return send_done;
	183	goto out_err;
	184	}
	185	send_done += chunk_len;
	186	send_remaining -= chunk_len;
	187
	188	if (chunk_len_sum == copylen)
	189	break; /* either on 1st or 2nd iteration */
	190	/* prepare next (== 2nd) iteration */
	191	chunk_len = copylen - chunk_len; /* remainder */
	192	chunk_len_sum += chunk_len;
	193	chunk_off = 0; /* modulo offset in send ring buffer */
	194	}
	195	/* update cursors */
	196	smc_curs_add(conn->sndbuf_size, &prep, copylen);
	197	smc_curs_write(&conn->tx_curs_prep,
	198	smc_curs_read(&prep, conn),
	199	conn);
	200	/* increased in send tasklet smc_cdc_tx_handler() */
	201	smp_mb__before_atomic();
	202	atomic_sub(copylen, &conn->sndbuf_space);
	203	/* guarantee 0 <= sndbuf_space <= sndbuf_size */
	204	smp_mb__after_atomic();
	205	/* since we just produced more new data into sndbuf,
	206	* trigger sndbuf consumer: RDMA write into peer RMBE and CDC
	207	*/
	208	smc_tx_sndbuf_nonempty(conn);
209	} /* while (msg_data_left(msg)) */
210
211	return send_done;
212
213	out_err:
214	rc = sk_stream_error(sk, msg->msg_flags, rc);
215	/* make sure we wake any epoll edge trigger waiter */
216	if (unlikely(rc == -EAGAIN))
217	sk->sk_write_space(sk);
218	return rc;
219	}
220
221	/*************************** sndbuf consumer *****************************/
222
223	/* sndbuf consumer: actual data transfer of one target chunk with RDMA write */
224	static int smc_tx_rdma_write(struct smc_connection *conn, int peer_rmbe_offset,
225	int num_sges, struct ib_sge sges[])
226	{
227	struct smc_link_group *lgr = conn->lgr;
228	struct ib_send_wr *failed_wr = NULL;
229	struct ib_rdma_wr rdma_wr;
230	struct smc_link *link;
231	int rc;
232
233	memset(&rdma_wr, 0, sizeof(rdma_wr));
234	link = &lgr->lnk[SMC_SINGLE_LINK];
235	rdma_wr.wr.wr_id = smc_wr_tx_get_next_wr_id(link);
236	rdma_wr.wr.sg_list = sges;
237	rdma_wr.wr.num_sge = num_sges;
238	rdma_wr.wr.opcode = IB_WR_RDMA_WRITE;
239	rdma_wr.remote_addr =
240	lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].dma_addr +
241	/* RMBE within RMB */
242	((conn->peer_conn_idx - 1) * conn->peer_rmbe_size) +
243	/* offset within RMBE */
244	peer_rmbe_offset;
245	rdma_wr.rkey = lgr->rtokens[conn->rtoken_idx][SMC_SINGLE_LINK].rkey;
246	rc = ib_post_send(link->roce_qp, &rdma_wr.wr, &failed_wr);
247	if (rc)
248	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
249	return rc;
250	}
251
252	/* sndbuf consumer */
253	static inline void smc_tx_advance_cursors(struct smc_connection *conn,
254	union smc_host_cursor *prod,
255	union smc_host_cursor *sent,
256	size_t len)
257	{
258	smc_curs_add(conn->peer_rmbe_size, prod, len);
259	/* increased in recv tasklet smc_cdc_msg_rcv() */
260	smp_mb__before_atomic();
261	/* data in flight reduces usable snd_wnd */
262	atomic_sub(len, &conn->peer_rmbe_space);
263	/* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
264	smp_mb__after_atomic();
265	smc_curs_add(conn->sndbuf_size, sent, len);
266	}
267
268	/* sndbuf consumer: prepare all necessary (src&dst) chunks of data transmit;
269	* usable snd_wnd as max transmit
270	*/
271	static int smc_tx_rdma_writes(struct smc_connection *conn)
272	{
273	size_t src_off, src_len, dst_off, dst_len; /* current chunk values */
274	size_t len, dst_len_sum, src_len_sum, dstchunk, srcchunk;
275	union smc_host_cursor sent, prep, prod, cons;
276	struct ib_sge sges[SMC_IB_MAX_SEND_SGE];
277	struct smc_link_group *lgr = conn->lgr;
278	int to_send, rmbespace;
279	struct smc_link *link;
280	int num_sges;
281	int rc;
282
283	/* source: sndbuf */
284	smc_curs_write(&sent, smc_curs_read(&conn->tx_curs_sent, conn), conn);
285	smc_curs_write(&prep, smc_curs_read(&conn->tx_curs_prep, conn), conn);
286	/* cf. wmem_alloc - (snd_max - snd_una) */
287	to_send = smc_curs_diff(conn->sndbuf_size, &sent, &prep);
288	if (to_send <= 0)
289	return 0;
290
291	/* destination: RMBE */
292	/* cf. snd_wnd */
293	rmbespace = atomic_read(&conn->peer_rmbe_space);
294	if (rmbespace <= 0)
295	return 0;
296	smc_curs_write(&prod,
297	smc_curs_read(&conn->local_tx_ctrl.prod, conn),
298	conn);
299	smc_curs_write(&cons,
300	smc_curs_read(&conn->local_rx_ctrl.cons, conn),
301	conn);
302
303	/* if usable snd_wnd closes ask peer to advertise once it opens again */
304	conn->local_tx_ctrl.prod_flags.write_blocked = (to_send >= rmbespace);
305	/* cf. usable snd_wnd */
306	len = min(to_send, rmbespace);
307
308	/* initialize variables for first iteration of subsequent nested loop */
309	link = &lgr->lnk[SMC_SINGLE_LINK];
310	dst_off = prod.count;
311	if (prod.wrap == cons.wrap) {
312	/* the filled destination area is unwrapped,
313	* hence the available free destination space is wrapped
314	* and we need 2 destination chunks of sum len; start with 1st
315	* which is limited by what's available in sndbuf
316	*/
317	dst_len = min_t(size_t,
318	conn->peer_rmbe_size - prod.count, len);
319	} else {
320	/* the filled destination area is wrapped,
321	* hence the available free destination space is unwrapped
322	* and we need a single destination chunk of entire len
323	*/
324	dst_len = len;
325	}
326	dst_len_sum = dst_len;
327	src_off = sent.count;
328	/* dst_len determines the maximum src_len */
329	if (sent.count + dst_len <= conn->sndbuf_size) {
330	/* unwrapped src case: single chunk of entire dst_len */
331	src_len = dst_len;
332	} else {
333	/* wrapped src case: 2 chunks of sum dst_len; start with 1st: */
334	src_len = conn->sndbuf_size - sent.count;
335	}
336	src_len_sum = src_len;
337	for (dstchunk = 0; dstchunk < 2; dstchunk++) {
338	num_sges = 0;
339	for (srcchunk = 0; srcchunk < 2; srcchunk++) {
340	sges[srcchunk].addr =
341	conn->sndbuf_desc->dma_addr[SMC_SINGLE_LINK] +
342	src_off;
343	sges[srcchunk].length = src_len;
344	sges[srcchunk].lkey = link->roce_pd->local_dma_lkey;
345	num_sges++;
346	src_off += src_len;
347	if (src_off >= conn->sndbuf_size)
348	src_off -= conn->sndbuf_size;
349	/* modulo in send ring */
350	if (src_len_sum == dst_len)
351	break; /* either on 1st or 2nd iteration */
352	/* prepare next (== 2nd) iteration */
353	src_len = dst_len - src_len; /* remainder */
354	src_len_sum += src_len;
355	}
356	rc = smc_tx_rdma_write(conn, dst_off, num_sges, sges);
357	if (rc)
358	return rc;
359	if (dst_len_sum == len)
360	break; /* either on 1st or 2nd iteration */
361	/* prepare next (== 2nd) iteration */
362	dst_off = 0; /* modulo offset in RMBE ring buffer */
363	dst_len = len - dst_len; /* remainder */
364	dst_len_sum += dst_len;
365	src_len = min_t(int,
366	dst_len, conn->sndbuf_size - sent.count);
367	src_len_sum = src_len;
368	}
369
370	smc_tx_advance_cursors(conn, &prod, &sent, len);
371	/* update connection's cursors with advanced local cursors */
372	smc_curs_write(&conn->local_tx_ctrl.prod,
373	smc_curs_read(&prod, conn),
374	conn);
375	/* dst: peer RMBE */
376	smc_curs_write(&conn->tx_curs_sent,
377	smc_curs_read(&sent, conn),
378	conn);
379	/* src: local sndbuf */
380
381	return 0;
382	}
383
384	/* Wakeup sndbuf consumers from any context (IRQ or process)
385	* since there is more data to transmit; usable snd_wnd as max transmit
386	*/
387	int smc_tx_sndbuf_nonempty(struct smc_connection *conn)
388	{
389	struct smc_cdc_tx_pend *pend;
390	struct smc_wr_buf *wr_buf;
391	int rc;
392
393	spin_lock_bh(&conn->send_lock);
394	rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf,
395	&pend);
396	if (rc < 0) {
397	if (rc == -EBUSY) {
b38d7324 UB	398	struct smc_sock *smc =
	399	container_of(conn, struct smc_sock, conn);
	400
	401	if (smc->sk.sk_err == ECONNABORTED) {
	402	rc = sock_error(&smc->sk);
	403	goto out_unlock;
	404	}
e6727f39 UB	405	rc = 0;
	406	schedule_work(&conn->tx_work);
	407	}
	408	goto out_unlock;
	409	}
	410
	411	rc = smc_tx_rdma_writes(conn);
	412	if (rc) {
	413	smc_wr_tx_put_slot(&conn->lgr->lnk[SMC_SINGLE_LINK],
	414	(struct smc_wr_tx_pend_priv *)pend);
	415	goto out_unlock;
	416	}
	417
	418	rc = smc_cdc_msg_send(conn, wr_buf, pend);
	419
	420	out_unlock:
	421	spin_unlock_bh(&conn->send_lock);
	422	return rc;
	423	}
	424
	425	/* Wakeup sndbuf consumers from process context
	426	* since there is more data to transmit
	427	*/
	428	static void smc_tx_work(struct work_struct *work)
	429	{
	430	struct smc_connection *conn = container_of(work,
	431	struct smc_connection,
	432	tx_work);
	433	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
90cacb2e	434	int rc;
e6727f39 UB	435
e6727f39 UB	436	lock_sock(&smc->sk);
90cacb2e UB	437	rc = smc_tx_sndbuf_nonempty(conn);
	438	if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked &&
	439	!atomic_read(&conn->bytes_to_rcv))
	440	conn->local_rx_ctrl.prod_flags.write_blocked = 0;
e6727f39 UB	441	release_sock(&smc->sk);
	442	}
	443
952310cc UB	444	void smc_tx_consumer_update(struct smc_connection *conn)
	445	{
	446	union smc_host_cursor cfed, cons;
	447	struct smc_cdc_tx_pend *pend;
	448	struct smc_wr_buf *wr_buf;
	449	int to_confirm, rc;
	450
	451	smc_curs_write(&cons,
	452	smc_curs_read(&conn->local_tx_ctrl.cons, conn),
	453	conn);
	454	smc_curs_write(&cfed,
	455	smc_curs_read(&conn->rx_curs_confirmed, conn),
	456	conn);
	457	to_confirm = smc_curs_diff(conn->rmbe_size, &cfed, &cons);
	458
	459	if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req \|\|
	460	((to_confirm > conn->rmbe_update_limit) &&
	461	((to_confirm > (conn->rmbe_size / 2)) \|\|
	462	conn->local_rx_ctrl.prod_flags.write_blocked))) {
	463	rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK],
	464	&wr_buf, &pend);
	465	if (!rc)
	466	rc = smc_cdc_msg_send(conn, wr_buf, pend);
	467	if (rc < 0) {
	468	schedule_work(&conn->tx_work);
	469	return;
	470	}
	471	smc_curs_write(&conn->rx_curs_confirmed,
	472	smc_curs_read(&conn->local_tx_ctrl.cons, conn),
	473	conn);
	474	conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
	475	}
	476	if (conn->local_rx_ctrl.prod_flags.write_blocked &&
	477	!atomic_read(&conn->bytes_to_rcv))
	478	conn->local_rx_ctrl.prod_flags.write_blocked = 0;
	479	}
	480
e6727f39 UB	481	/*************************** send initialize *****************************/
	482
	483	/* Initialize send properties on connection establishment. NB: not __init! */
	484	void smc_tx_init(struct smc_sock *smc)
	485	{
	486	smc->sk.sk_write_space = smc_tx_write_space;
	487	INIT_WORK(&smc->conn.tx_work, smc_tx_work);
	488	spin_lock_init(&smc->conn.send_lock);
	489	}