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

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 * Connection Data Control (CDC)
 *
 * Copyright IBM Corp. 2016
 *
 * Author(s):  Ursula Braun <[email protected]>
 */

#ifndef SMC_CDC_H
#define SMC_CDC_H

#include <linux/kernel.h> /* max_t */
#include <linux/atomic.h>
#include <linux/in.h>
#include <linux/compiler.h>

#include "smc.h"
#include "smc_core.h"
#include "smc_wr.h"

#define	SMC_CDC_MSG_TYPE		0xFE

/* in network byte order */
union smc_cdc_cursor {		/* SMC cursor */
	struct {
		__be16	reserved;
		__be16	wrap;
		__be32	count;
	};
#ifdef KERNEL_HAS_ATOMIC64
	atomic64_t	acurs;		/* for atomic processing */
#else
	u64		acurs;		/* for atomic processing */
#endif
} __aligned(8);

/* in network byte order */
struct smc_cdc_msg {
	struct smc_wr_rx_hdr		common; /* .type = 0xFE */
	u8				len;	/* 44 */
	__be16				seqno;
	__be32				token;
	union smc_cdc_cursor		prod;
	union smc_cdc_cursor		cons;	/* piggy backed "ack" */
	struct smc_cdc_producer_flags	prod_flags;
	struct smc_cdc_conn_state_flags	conn_state_flags;
	u8				reserved[18];
} __packed;					/* format defined in RFC7609 */

static inline bool smc_cdc_rxed_any_close(struct smc_connection *conn)
{
	return conn->local_rx_ctrl.conn_state_flags.peer_conn_abort ||
	       conn->local_rx_ctrl.conn_state_flags.peer_conn_closed;
}

static inline bool smc_cdc_rxed_any_close_or_senddone(
	struct smc_connection *conn)
{
	return smc_cdc_rxed_any_close(conn) ||
	       conn->local_rx_ctrl.conn_state_flags.peer_done_writing;
}

static inline void smc_curs_add(int size, union smc_host_cursor *curs,
				int value)
{
	curs->count += value;
	if (curs->count >= size) {
		curs->wrap++;
		curs->count -= size;
	}
}

/* SMC cursors are 8 bytes long and require atomic reading and writing */
static inline u64 smc_curs_read(union smc_host_cursor *curs,
				struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;
	u64 ret;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	ret = curs->acurs;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
	return ret;
#else
	return atomic64_read(&curs->acurs);
#endif
}

static inline u64 smc_curs_read_net(union smc_cdc_cursor *curs,
				    struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;
	u64 ret;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	ret = curs->acurs;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
	return ret;
#else
	return atomic64_read(&curs->acurs);
#endif
}

static inline void smc_curs_write(union smc_host_cursor *curs, u64 val,
				  struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	curs->acurs = val;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
#else
	atomic64_set(&curs->acurs, val);
#endif
}

static inline void smc_curs_write_net(union smc_cdc_cursor *curs, u64 val,
				      struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	curs->acurs = val;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
#else
	atomic64_set(&curs->acurs, val);
#endif
}

/* calculate cursor difference between old and new, where old <= new */
static inline int smc_curs_diff(unsigned int size,
				union smc_host_cursor *old,
				union smc_host_cursor *new)
{
	if (old->wrap != new->wrap)
		return max_t(int, 0,
			     ((size - old->count) + new->count));

	return max_t(int, 0, (new->count - old->count));
}

/* calculate cursor difference between old and new - returns negative
 * value in case old > new
 */
static inline int smc_curs_comp(unsigned int size,
				union smc_host_cursor *old,
				union smc_host_cursor *new)
{
	if (old->wrap > new->wrap ||
	    (old->wrap == new->wrap && old->count > new->count))
		return -smc_curs_diff(size, new, old);
	return smc_curs_diff(size, old, new);
}

static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
					  union smc_host_cursor *local,
					  struct smc_connection *conn)
{
	union smc_host_cursor temp;

	smc_curs_write(&temp, smc_curs_read(local, conn), conn);
	peer->count = htonl(temp.count);
	peer->wrap = htons(temp.wrap);
	/* peer->reserved = htons(0); must be ensured by caller */
}

static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
				       struct smc_host_cdc_msg *local,
				       struct smc_connection *conn)
{
	peer->common.type = local->common.type;
	peer->len = local->len;
	peer->seqno = htons(local->seqno);
	peer->token = htonl(local->token);
	smc_host_cursor_to_cdc(&peer->prod, &local->prod, conn);
	smc_host_cursor_to_cdc(&peer->cons, &local->cons, conn);
	peer->prod_flags = local->prod_flags;
	peer->conn_state_flags = local->conn_state_flags;
}

static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
					  union smc_cdc_cursor *peer,
					  struct smc_connection *conn)
{
	union smc_host_cursor temp, old;
	union smc_cdc_cursor net;

	smc_curs_write(&old, smc_curs_read(local, conn), conn);
	smc_curs_write_net(&net, smc_curs_read_net(peer, conn), conn);
	temp.count = ntohl(net.count);
	temp.wrap = ntohs(net.wrap);
	if ((old.wrap > temp.wrap) && temp.wrap)
		return;
	if ((old.wrap == temp.wrap) &&
	    (old.count > temp.count))
		return;
	smc_curs_write(local, smc_curs_read(&temp, conn), conn);
}

static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
				       struct smc_cdc_msg *peer,
				       struct smc_connection *conn)
{
	local->common.type = peer->common.type;
	local->len = peer->len;
	local->seqno = ntohs(peer->seqno);
	local->token = ntohl(peer->token);
	smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
	smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
	local->prod_flags = peer->prod_flags;
	local->conn_state_flags = peer->conn_state_flags;
}

struct smc_cdc_tx_pend;

int smc_cdc_get_free_slot(struct smc_connection *conn,
			  struct smc_wr_buf **wr_buf,
			  struct smc_cdc_tx_pend **pend);
void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
		     struct smc_cdc_tx_pend *pend);
int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
int smc_cdc_init(void) __init;

#endif /* SMC_CDC_H */
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	*
	7	* Copyright IBM Corp. 2016
	8	*
	9	* Author(s): Ursula Braun <[email protected]>
	10	*/
	11
	12	#ifndef SMC_CDC_H
	13	#define SMC_CDC_H
	14
	15	#include <linux/kernel.h> /* max_t */
	16	#include <linux/atomic.h>
	17	#include <linux/in.h>
	18	#include <linux/compiler.h>
	19
	20	#include "smc.h"
	21	#include "smc_core.h"
	22	#include "smc_wr.h"
	23
	24	#define SMC_CDC_MSG_TYPE 0xFE
	25
	26	/* in network byte order */
	27	union smc_cdc_cursor { /* SMC cursor */
	28	struct {
	29	__be16 reserved;
	30	__be16 wrap;
	31	__be32 count;
	32	};
	33	#ifdef KERNEL_HAS_ATOMIC64
	34	atomic64_t acurs; /* for atomic processing */
	35	#else
	36	u64 acurs; /* for atomic processing */
	37	#endif
	38	} __aligned(8);
	39
	40	/* in network byte order */
	41	struct smc_cdc_msg {
	42	struct smc_wr_rx_hdr common; /* .type = 0xFE */
	43	u8 len; /* 44 */
	44	__be16 seqno;
	45	__be32 token;
	46	union smc_cdc_cursor prod;
	47	union smc_cdc_cursor cons; /* piggy backed "ack" */
	48	struct smc_cdc_producer_flags prod_flags;
	49	struct smc_cdc_conn_state_flags conn_state_flags;
	50	u8 reserved[18];
33825761	51	} __packed; /* format defined in RFC7609 */
5f08318f UB	52
	53	static inline bool smc_cdc_rxed_any_close(struct smc_connection *conn)
	54	{
	55	return conn->local_rx_ctrl.conn_state_flags.peer_conn_abort \|\|
	56	conn->local_rx_ctrl.conn_state_flags.peer_conn_closed;
	57	}
	58
	59	static inline bool smc_cdc_rxed_any_close_or_senddone(
	60	struct smc_connection *conn)
	61	{
	62	return smc_cdc_rxed_any_close(conn) \|\|
	63	conn->local_rx_ctrl.conn_state_flags.peer_done_writing;
	64	}
	65
	66	static inline void smc_curs_add(int size, union smc_host_cursor *curs,
	67	int value)
	68	{
	69	curs->count += value;
	70	if (curs->count >= size) {
	71	curs->wrap++;
	72	curs->count -= size;
	73	}
	74	}
	75
	76	/* SMC cursors are 8 bytes long and require atomic reading and writing */
	77	static inline u64 smc_curs_read(union smc_host_cursor *curs,
	78	struct smc_connection *conn)
	79	{
	80	#ifndef KERNEL_HAS_ATOMIC64
	81	unsigned long flags;
	82	u64 ret;
	83
	84	spin_lock_irqsave(&conn->acurs_lock, flags);
	85	ret = curs->acurs;
	86	spin_unlock_irqrestore(&conn->acurs_lock, flags);
	87	return ret;
	88	#else
	89	return atomic64_read(&curs->acurs);
	90	#endif
	91	}
	92
	93	static inline u64 smc_curs_read_net(union smc_cdc_cursor *curs,
	94	struct smc_connection *conn)
	95	{
	96	#ifndef KERNEL_HAS_ATOMIC64
	97	unsigned long flags;
	98	u64 ret;
	99
	100	spin_lock_irqsave(&conn->acurs_lock, flags);
	101	ret = curs->acurs;
	102	spin_unlock_irqrestore(&conn->acurs_lock, flags);
	103	return ret;
	104	#else
	105	return atomic64_read(&curs->acurs);
	106	#endif
	107	}
	108
	109	static inline void smc_curs_write(union smc_host_cursor *curs, u64 val,
	110	struct smc_connection *conn)
	111	{
	112	#ifndef KERNEL_HAS_ATOMIC64
	113	unsigned long flags;
	114
	115	spin_lock_irqsave(&conn->acurs_lock, flags);
116	curs->acurs = val;
117	spin_unlock_irqrestore(&conn->acurs_lock, flags);
118	#else
119	atomic64_set(&curs->acurs, val);
120	#endif
121	}
122
123	static inline void smc_curs_write_net(union smc_cdc_cursor *curs, u64 val,
124	struct smc_connection *conn)
125	{
126	#ifndef KERNEL_HAS_ATOMIC64
127	unsigned long flags;
128
129	spin_lock_irqsave(&conn->acurs_lock, flags);
130	curs->acurs = val;
131	spin_unlock_irqrestore(&conn->acurs_lock, flags);
132	#else
133	atomic64_set(&curs->acurs, val);
134	#endif
135	}
136
137	/* calculate cursor difference between old and new, where old <= new */
138	static inline int smc_curs_diff(unsigned int size,
139	union smc_host_cursor *old,
140	union smc_host_cursor *new)
141	{
142	if (old->wrap != new->wrap)
143	return max_t(int, 0,
144	((size - old->count) + new->count));
145
146	return max_t(int, 0, (new->count - old->count));
147	}
148
de8474eb SR	149	/* calculate cursor difference between old and new - returns negative
	150	* value in case old > new
	151	*/
	152	static inline int smc_curs_comp(unsigned int size,
	153	union smc_host_cursor *old,
	154	union smc_host_cursor *new)
	155	{
	156	if (old->wrap > new->wrap \|\|
	157	(old->wrap == new->wrap && old->count > new->count))
	158	return -smc_curs_diff(size, new, old);
	159	return smc_curs_diff(size, old, new);
	160	}
	161
5f08318f UB	162	static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
	163	union smc_host_cursor *local,
	164	struct smc_connection *conn)
	165	{
	166	union smc_host_cursor temp;
	167
	168	smc_curs_write(&temp, smc_curs_read(local, conn), conn);
	169	peer->count = htonl(temp.count);
	170	peer->wrap = htons(temp.wrap);
	171	/* peer->reserved = htons(0); must be ensured by caller */
	172	}
	173
	174	static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
	175	struct smc_host_cdc_msg *local,
	176	struct smc_connection *conn)
	177	{
	178	peer->common.type = local->common.type;
	179	peer->len = local->len;
	180	peer->seqno = htons(local->seqno);
	181	peer->token = htonl(local->token);
	182	smc_host_cursor_to_cdc(&peer->prod, &local->prod, conn);
	183	smc_host_cursor_to_cdc(&peer->cons, &local->cons, conn);
	184	peer->prod_flags = local->prod_flags;
	185	peer->conn_state_flags = local->conn_state_flags;
	186	}
	187
	188	static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
	189	union smc_cdc_cursor *peer,
	190	struct smc_connection *conn)
	191	{
	192	union smc_host_cursor temp, old;
	193	union smc_cdc_cursor net;
	194
	195	smc_curs_write(&old, smc_curs_read(local, conn), conn);
	196	smc_curs_write_net(&net, smc_curs_read_net(peer, conn), conn);
	197	temp.count = ntohl(net.count);
	198	temp.wrap = ntohs(net.wrap);
	199	if ((old.wrap > temp.wrap) && temp.wrap)
	200	return;
	201	if ((old.wrap == temp.wrap) &&
	202	(old.count > temp.count))
	203	return;
	204	smc_curs_write(local, smc_curs_read(&temp, conn), conn);
	205	}
	206
	207	static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
	208	struct smc_cdc_msg *peer,
	209	struct smc_connection *conn)
	210	{
	211	local->common.type = peer->common.type;
	212	local->len = peer->len;
	213	local->seqno = ntohs(peer->seqno);
	214	local->token = ntohl(peer->token);
	215	smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
	216	smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
	217	local->prod_flags = peer->prod_flags;
	218	local->conn_state_flags = peer->conn_state_flags;
	219	}
	220
	221	struct smc_cdc_tx_pend;
	222
51957bc5 UB	223	int smc_cdc_get_free_slot(struct smc_connection *conn,
51957bc5 UB	224	struct smc_wr_buf **wr_buf,
5f08318f UB	225	struct smc_cdc_tx_pend **pend);
	226	void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
	227	int smc_cdc_msg_send(struct smc_connection conn, struct smc_wr_buf wr_buf,
	228	struct smc_cdc_tx_pend *pend);
	229	int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
	230	int smc_cdc_init(void) __init;
	231
	232	#endif /* SMC_CDC_H */