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/* 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 <ubraun@linux.vnet.ibm.com>
*/
#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 */
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