net/smc/smc.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
  *
  *  Definitions for the SMC module (socket related)
  *
  *  Copyright IBM Corp. 2016
  *
  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  */
 #ifndef __SMC_H
 #define __SMC_H

 #include <linux/socket.h>
 #include <linux/types.h>
 #include <linux/compiler.h> /* __aligned */
 #include <net/genetlink.h>
 #include <net/sock.h>

 #include "smc_ib.h"

 #define SMC_V1		1		/* SMC version V1 */
 #define SMC_V2		2		/* SMC version V2 */

 #define SMC_RELEASE_0 0
 #define SMC_RELEASE_1 1
 #define SMC_RELEASE	SMC_RELEASE_1 /* the latest release version */

 #define SMCPROTO_SMC		0	/* SMC protocol, IPv4 */
 #define SMCPROTO_SMC6		1	/* SMC protocol, IPv6 */

 #define SMC_AUTOCORKING_DEFAULT_SIZE	0x10000	/* 64K by default */

 extern struct proto smc_proto;
 extern struct proto smc_proto6;

 #ifdef ATOMIC64_INIT
 #define KERNEL_HAS_ATOMIC64
 #endif

 enum smc_state {		/* possible states of an SMC socket */
 	SMC_ACTIVE	= 1,
 	SMC_INIT	= 2,
 	SMC_CLOSED	= 7,
 	SMC_LISTEN	= 10,
 	/* normal close */
 	SMC_PEERCLOSEWAIT1	= 20,
 	SMC_PEERCLOSEWAIT2	= 21,
 	SMC_APPFINCLOSEWAIT	= 24,
 	SMC_APPCLOSEWAIT1	= 22,
 	SMC_APPCLOSEWAIT2	= 23,
 	SMC_PEERFINCLOSEWAIT	= 25,
 	/* abnormal close */
 	SMC_PEERABORTWAIT	= 26,
 	SMC_PROCESSABORT	= 27,
 };

 enum smc_supplemental_features {
 	SMC_SPF_EMULATED_ISM_DEV	= 0,
 };

 #define SMC_FEATURE_MASK \
 	(BIT(SMC_SPF_EMULATED_ISM_DEV))

 struct smc_link_group;

 struct smc_wr_rx_hdr {	/* common prefix part of LLC and CDC to demultiplex */
 	union {
 		u8 type;
 #if defined(__BIG_ENDIAN_BITFIELD)
 		struct {
 			u8 llc_version:4,
 			   llc_type:4;
 		};
 #elif defined(__LITTLE_ENDIAN_BITFIELD)
 		struct {
 			u8 llc_type:4,
 			   llc_version:4;
 		};
 #endif
 	};
 } __aligned(1);

 struct smc_cdc_conn_state_flags {
 #if defined(__BIG_ENDIAN_BITFIELD)
 	u8	peer_done_writing : 1;	/* Sending done indicator */
 	u8	peer_conn_closed : 1;	/* Peer connection closed indicator */
 	u8	peer_conn_abort : 1;	/* Abnormal close indicator */
 	u8	reserved : 5;
 #elif defined(__LITTLE_ENDIAN_BITFIELD)
 	u8	reserved : 5;
 	u8	peer_conn_abort : 1;
 	u8	peer_conn_closed : 1;
 	u8	peer_done_writing : 1;
 #endif
 };

 struct smc_cdc_producer_flags {
 #if defined(__BIG_ENDIAN_BITFIELD)
 	u8	write_blocked : 1;	/* Writing Blocked, no rx buf space */
 	u8	urg_data_pending : 1;	/* Urgent Data Pending */
 	u8	urg_data_present : 1;	/* Urgent Data Present */
 	u8	cons_curs_upd_req : 1;	/* cursor update requested */
 	u8	failover_validation : 1;/* message replay due to failover */
 	u8	reserved : 3;
 #elif defined(__LITTLE_ENDIAN_BITFIELD)
 	u8	reserved : 3;
 	u8	failover_validation : 1;
 	u8	cons_curs_upd_req : 1;
 	u8	urg_data_present : 1;
 	u8	urg_data_pending : 1;
 	u8	write_blocked : 1;
 #endif
 };

 /* in host byte order */
 union smc_host_cursor {	/* SMC cursor - an offset in an RMBE */
 	struct {
 		u16	reserved;
 		u16	wrap;		/* window wrap sequence number */
 		u32	count;		/* cursor (= offset) part */
 	};
 #ifdef KERNEL_HAS_ATOMIC64
 	atomic64_t		acurs;	/* for atomic processing */
 #else
 	u64			acurs;	/* for atomic processing */
 #endif
 } __aligned(8);

 /* in host byte order, except for flag bitfields in network byte order */
 struct smc_host_cdc_msg {		/* Connection Data Control message */
 	struct smc_wr_rx_hdr		common; /* .type = 0xFE */
 	u8				len;	/* length = 44 */
 	u16				seqno;	/* connection seq # */
 	u32				token;	/* alert_token */
 	union smc_host_cursor		prod;		/* producer cursor */
 	union smc_host_cursor		cons;		/* consumer cursor,
 							 * piggy backed "ack"
 							 */
 	struct smc_cdc_producer_flags	prod_flags;	/* conn. tx/rx status */
 	struct smc_cdc_conn_state_flags	conn_state_flags; /* peer conn. status*/
 	u8				reserved[18];
 } __aligned(8);

 enum smc_urg_state {
 	SMC_URG_VALID	= 1,			/* data present */
 	SMC_URG_NOTYET	= 2,			/* data pending */
 	SMC_URG_READ	= 3,			/* data was already read */
 };

 struct smc_mark_woken {
 	bool woken;
 	void *key;
 	wait_queue_entry_t wait_entry;
 };

 struct smc_connection {
 	struct rb_node		alert_node;
 	struct smc_link_group	*lgr;		/* link group of connection */
 	struct smc_link		*lnk;		/* assigned SMC-R link */
 	u32			alert_token_local; /* unique conn. id */
 	u8			peer_rmbe_idx;	/* from tcp handshake */
 	int			peer_rmbe_size;	/* size of peer rx buffer */
 	atomic_t		peer_rmbe_space;/* remaining free bytes in peer
 						 * rmbe
 						 */
 	int			rtoken_idx;	/* idx to peer RMB rkey/addr */

 	struct smc_buf_desc	*sndbuf_desc;	/* send buffer descriptor */
 	struct smc_buf_desc	*rmb_desc;	/* RMBE descriptor */
 	int                     rmbe_size_comp; /* compressed notation */
 	int			rmbe_update_limit;
 						/* lower limit for consumer
 						 * cursor update
 						 */

 	struct smc_host_cdc_msg	local_tx_ctrl;	/* host byte order staging
 						 * buffer for CDC msg send
 						 * .prod cf. TCP snd_nxt
 						 * .cons cf. TCP sends ack
 						 */
 	union smc_host_cursor	local_tx_ctrl_fin;
 						/* prod crsr - confirmed by peer
 						 */
 	union smc_host_cursor	tx_curs_prep;	/* tx - prepared data
 						 * snd_max..wmem_alloc
 						 */
 	union smc_host_cursor	tx_curs_sent;	/* tx - sent data
 						 * snd_nxt ?
 						 */
 	union smc_host_cursor	tx_curs_fin;	/* tx - confirmed by peer
 						 * snd-wnd-begin ?
 						 */
 	atomic_t		sndbuf_space;	/* remaining space in sndbuf */
 	u16			tx_cdc_seq;	/* sequence # for CDC send */
 	u16			tx_cdc_seq_fin;	/* sequence # - tx completed */
 	spinlock_t		send_lock;	/* protect wr_sends */
 	atomic_t		cdc_pend_tx_wr; /* number of pending tx CDC wqe
 						 * - inc when post wqe,
 						 * - dec on polled tx cqe
 						 */
 	wait_queue_head_t	cdc_pend_tx_wq; /* wakeup on no cdc_pend_tx_wr*/
 	struct delayed_work	tx_work;	/* retry of smc_cdc_msg_send */
 	u32			tx_off;		/* base offset in peer rmb */

 	struct smc_host_cdc_msg	local_rx_ctrl;	/* filled during event_handl.
 						 * .prod cf. TCP rcv_nxt
 						 * .cons cf. TCP snd_una
 						 */
 	union smc_host_cursor	rx_curs_confirmed; /* confirmed to peer
 						    * source of snd_una ?
 						    */
 	union smc_host_cursor	urg_curs;	/* points at urgent byte */
 	enum smc_urg_state	urg_state;
 	bool			urg_tx_pend;	/* urgent data staged */
 	bool			urg_rx_skip_pend;
 						/* indicate urgent oob data
 						 * read, but previous regular
 						 * data still pending
 						 */
 	char			urg_rx_byte;	/* urgent byte */
 	bool			tx_in_release_sock;
 						/* flush pending tx data in
 						 * sock release_cb()
 						 */
 	atomic_t		bytes_to_rcv;	/* arrived data,
 						 * not yet received
 						 */
 	atomic_t		splice_pending;	/* number of spliced bytes
 						 * pending processing
 						 */
 #ifndef KERNEL_HAS_ATOMIC64
 	spinlock_t		acurs_lock;	/* protect cursors */
 #endif
 	struct work_struct	close_work;	/* peer sent some closing */
 	struct work_struct	abort_work;	/* abort the connection */
 	struct tasklet_struct	rx_tsklet;	/* Receiver tasklet for SMC-D */
 	u8			rx_off;		/* receive offset:
 						 * 0 for SMC-R, 32 for SMC-D
 						 */
 	u64			peer_token;	/* SMC-D token of peer */
 	u8			killed : 1;	/* abnormal termination */
 	u8			freed : 1;	/* normal termiation */
 	u8			out_of_sync : 1; /* out of sync with peer */
 };

 struct smc_sock {				/* smc sock container */
 	struct sock		sk;
 	struct socket		*clcsock;	/* internal tcp socket */
 	void			(*clcsk_state_change)(struct sock *sk);
 						/* original stat_change fct. */
 	void			(*clcsk_data_ready)(struct sock *sk);
 						/* original data_ready fct. */
 	void			(*clcsk_write_space)(struct sock *sk);
 						/* original write_space fct. */
 	void			(*clcsk_error_report)(struct sock *sk);
 						/* original error_report fct. */
 	struct smc_connection	conn;		/* smc connection */
 	struct smc_sock		*listen_smc;	/* listen parent */
 	struct work_struct	connect_work;	/* handle non-blocking connect*/
 	struct work_struct	tcp_listen_work;/* handle tcp socket accepts */
 	struct work_struct	smc_listen_work;/* prepare new accept socket */
 	struct list_head	accept_q;	/* sockets to be accepted */
 	spinlock_t		accept_q_lock;	/* protects accept_q */
 	bool			limit_smc_hs;	/* put constraint on handshake */
 	bool			use_fallback;	/* fallback to tcp */
 	int			fallback_rsn;	/* reason for fallback */
 	u32			peer_diagnosis; /* decline reason from peer */
 	atomic_t                queued_smc_hs;  /* queued smc handshakes */
 	struct inet_connection_sock_af_ops		af_ops;
 	const struct inet_connection_sock_af_ops	*ori_af_ops;
 						/* original af ops */
 	int			sockopt_defer_accept;
 						/* sockopt TCP_DEFER_ACCEPT
 						 * value
 						 */
 	u8			wait_close_tx_prepared : 1;
 						/* shutdown wr or close
 						 * started, waiting for unsent
 						 * data to be sent
 						 */
 	u8			connect_nonblock : 1;
 						/* non-blocking connect in
 						 * flight
 						 */
 	struct mutex            clcsock_release_lock;
 						/* protects clcsock of a listen
 						 * socket
 						 * */
 };

 #define smc_sk(ptr) container_of_const(ptr, struct smc_sock, sk)

 static inline void smc_init_saved_callbacks(struct smc_sock *smc)
 {
 	smc->clcsk_state_change	= NULL;
 	smc->clcsk_data_ready	= NULL;
 	smc->clcsk_write_space	= NULL;
 	smc->clcsk_error_report	= NULL;
 }

 static inline struct smc_sock *smc_clcsock_user_data(const struct sock *clcsk)
 {
 	return (struct smc_sock *)
 	       ((uintptr_t)clcsk->sk_user_data & ~SK_USER_DATA_NOCOPY);
 }

 /* save target_cb in saved_cb, and replace target_cb with new_cb */
 static inline void smc_clcsock_replace_cb(void (**target_cb)(struct sock *),
 					  void (*new_cb)(struct sock *),
 					  void (**saved_cb)(struct sock *))
 {
 	/* only save once */
 	if (!*saved_cb)
 		*saved_cb = *target_cb;
 	*target_cb = new_cb;
 }

 /* restore target_cb to saved_cb, and reset saved_cb to NULL */
 static inline void smc_clcsock_restore_cb(void (**target_cb)(struct sock *),
 					  void (**saved_cb)(struct sock *))
 {
 	if (!*saved_cb)
 		return;
 	*target_cb = *saved_cb;
 	*saved_cb = NULL;
 }

 extern struct workqueue_struct	*smc_hs_wq;	/* wq for handshake work */
 extern struct workqueue_struct	*smc_close_wq;	/* wq for close work */

 #define SMC_SYSTEMID_LEN		8

 extern u8	local_systemid[SMC_SYSTEMID_LEN]; /* unique system identifier */

 #define ntohll(x) be64_to_cpu(x)
 #define htonll(x) cpu_to_be64(x)

 /* convert an u32 value into network byte order, store it into a 3 byte field */
 static inline void hton24(u8 *net, u32 host)
 {
 	__be32 t;

 	t = cpu_to_be32(host);
 	memcpy(net, ((u8 *)&t) + 1, 3);
 }

 /* convert a received 3 byte field into host byte order*/
 static inline u32 ntoh24(u8 *net)
 {
 	__be32 t = 0;

 	memcpy(((u8 *)&t) + 1, net, 3);
 	return be32_to_cpu(t);
 }

 #ifdef CONFIG_XFRM
 static inline bool using_ipsec(struct smc_sock *smc)
 {
 	return (smc->clcsock->sk->sk_policy[0] ||
 		smc->clcsock->sk->sk_policy[1]) ? true : false;
 }
 #else
 static inline bool using_ipsec(struct smc_sock *smc)
 {
 	return false;
 }
 #endif

 struct smc_gidlist;

 struct sock *smc_accept_dequeue(struct sock *parent, struct socket *new_sock);
 void smc_close_non_accepted(struct sock *sk);
 void smc_fill_gid_list(struct smc_link_group *lgr,
 		       struct smc_gidlist *gidlist,
 		       struct smc_ib_device *known_dev, u8 *known_gid);

 /* smc handshake limitation interface for netlink  */
 int smc_nl_dump_hs_limitation(struct sk_buff *skb, struct netlink_callback *cb);
 int smc_nl_enable_hs_limitation(struct sk_buff *skb, struct genl_info *info);
 int smc_nl_disable_hs_limitation(struct sk_buff *skb, struct genl_info *info);

 static inline void smc_sock_set_flag(struct sock *sk, enum sock_flags flag)
 {
 	set_bit(flag, &sk->sk_flags);
 }

 #endif	/* __SMC_H */
	/* SPDX-License-Identifier: GPL-2.0 */
	/*
	* Shared Memory Communications over RDMA (SMC-R) and RoCE
	*
	* Definitions for the SMC module (socket related)
	*
	* Copyright IBM Corp. 2016
	*
	* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
	*/
	#ifndef __SMC_H
	#define __SMC_H

	#include <linux/socket.h>
	#include <linux/types.h>
	#include <linux/compiler.h> /* __aligned */
	#include <net/genetlink.h>
	#include <net/sock.h>

	#include "smc_ib.h"

	#define SMC_V1 1 /* SMC version V1 */
	#define SMC_V2 2 /* SMC version V2 */

	#define SMC_RELEASE_0 0
	#define SMC_RELEASE_1 1
	#define SMC_RELEASE SMC_RELEASE_1 /* the latest release version */

	#define SMCPROTO_SMC 0 /* SMC protocol, IPv4 */
	#define SMCPROTO_SMC6 1 /* SMC protocol, IPv6 */

	#define SMC_AUTOCORKING_DEFAULT_SIZE 0x10000 /* 64K by default */

	extern struct proto smc_proto;
	extern struct proto smc_proto6;

	#ifdef ATOMIC64_INIT
	#define KERNEL_HAS_ATOMIC64
	#endif

	enum smc_state { /* possible states of an SMC socket */
	SMC_ACTIVE = 1,
	SMC_INIT = 2,
	SMC_CLOSED = 7,
	SMC_LISTEN = 10,
	/* normal close */
	SMC_PEERCLOSEWAIT1 = 20,
	SMC_PEERCLOSEWAIT2 = 21,
	SMC_APPFINCLOSEWAIT = 24,
	SMC_APPCLOSEWAIT1 = 22,
	SMC_APPCLOSEWAIT2 = 23,
	SMC_PEERFINCLOSEWAIT = 25,
	/* abnormal close */
	SMC_PEERABORTWAIT = 26,
	SMC_PROCESSABORT = 27,
	};

	enum smc_supplemental_features {
	SMC_SPF_EMULATED_ISM_DEV = 0,
	};

	#define SMC_FEATURE_MASK \
	(BIT(SMC_SPF_EMULATED_ISM_DEV))

	struct smc_link_group;

	struct smc_wr_rx_hdr { /* common prefix part of LLC and CDC to demultiplex */
	union {
	u8 type;
	#if defined(__BIG_ENDIAN_BITFIELD)
	struct {
	u8 llc_version:4,
	llc_type:4;
	};
	#elif defined(__LITTLE_ENDIAN_BITFIELD)
	struct {
	u8 llc_type:4,
	llc_version:4;
	};
	#endif
	};
	} __aligned(1);

	struct smc_cdc_conn_state_flags {
	#if defined(__BIG_ENDIAN_BITFIELD)
	u8 peer_done_writing : 1; /* Sending done indicator */
	u8 peer_conn_closed : 1; /* Peer connection closed indicator */
	u8 peer_conn_abort : 1; /* Abnormal close indicator */
	u8 reserved : 5;
	#elif defined(__LITTLE_ENDIAN_BITFIELD)
	u8 reserved : 5;
	u8 peer_conn_abort : 1;
	u8 peer_conn_closed : 1;
	u8 peer_done_writing : 1;
	#endif
	};

	struct smc_cdc_producer_flags {
	#if defined(__BIG_ENDIAN_BITFIELD)
	u8 write_blocked : 1; /* Writing Blocked, no rx buf space */
	u8 urg_data_pending : 1; /* Urgent Data Pending */
	u8 urg_data_present : 1; /* Urgent Data Present */
	u8 cons_curs_upd_req : 1; /* cursor update requested */
	u8 failover_validation : 1;/* message replay due to failover */
	u8 reserved : 3;
	#elif defined(__LITTLE_ENDIAN_BITFIELD)
	u8 reserved : 3;
	u8 failover_validation : 1;
	u8 cons_curs_upd_req : 1;
	u8 urg_data_present : 1;
	u8 urg_data_pending : 1;
	u8 write_blocked : 1;
	#endif
	};

	/* in host byte order */
	union smc_host_cursor { /* SMC cursor - an offset in an RMBE */
	struct {
	u16 reserved;
	u16 wrap; /* window wrap sequence number */
	u32 count; /* cursor (= offset) part */
	};
	#ifdef KERNEL_HAS_ATOMIC64
	atomic64_t acurs; /* for atomic processing */
	#else
	u64 acurs; /* for atomic processing */
	#endif
	} __aligned(8);

	/* in host byte order, except for flag bitfields in network byte order */
	struct smc_host_cdc_msg { /* Connection Data Control message */
	struct smc_wr_rx_hdr common; /* .type = 0xFE */
	u8 len; /* length = 44 */
	u16 seqno; /* connection seq # */
	u32 token; /* alert_token */
	union smc_host_cursor prod; /* producer cursor */
	union smc_host_cursor cons; /* consumer cursor,
	* piggy backed "ack"
	*/
	struct smc_cdc_producer_flags prod_flags; /* conn. tx/rx status */
	struct smc_cdc_conn_state_flags conn_state_flags; /* peer conn. status*/
	u8 reserved[18];
	} __aligned(8);

	enum smc_urg_state {
	SMC_URG_VALID = 1, /* data present */
	SMC_URG_NOTYET = 2, /* data pending */
	SMC_URG_READ = 3, /* data was already read */
	};

	struct smc_mark_woken {
	bool woken;
	void *key;
	wait_queue_entry_t wait_entry;
	};

	struct smc_connection {
	struct rb_node alert_node;
	struct smc_link_group lgr; / link group of connection */
	struct smc_link lnk; / assigned SMC-R link */
	u32 alert_token_local; /* unique conn. id */
	u8 peer_rmbe_idx; /* from tcp handshake */
	int peer_rmbe_size; /* size of peer rx buffer */
	atomic_t peer_rmbe_space;/* remaining free bytes in peer
	* rmbe
	*/
	int rtoken_idx; /* idx to peer RMB rkey/addr */

	struct smc_buf_desc sndbuf_desc; / send buffer descriptor */
	struct smc_buf_desc rmb_desc; / RMBE descriptor */
	int rmbe_size_comp; /* compressed notation */
	int rmbe_update_limit;
	/* lower limit for consumer
	* cursor update
	*/

	struct smc_host_cdc_msg local_tx_ctrl; /* host byte order staging
	* buffer for CDC msg send
	* .prod cf. TCP snd_nxt
	* .cons cf. TCP sends ack
	*/
	union smc_host_cursor local_tx_ctrl_fin;
	/* prod crsr - confirmed by peer
	*/
	union smc_host_cursor tx_curs_prep; /* tx - prepared data
	* snd_max..wmem_alloc
	*/
	union smc_host_cursor tx_curs_sent; /* tx - sent data
	* snd_nxt ?
	*/
	union smc_host_cursor tx_curs_fin; /* tx - confirmed by peer
	* snd-wnd-begin ?
	*/
	atomic_t sndbuf_space; /* remaining space in sndbuf */
	u16 tx_cdc_seq; /* sequence # for CDC send */
	u16 tx_cdc_seq_fin; /* sequence # - tx completed */
	spinlock_t send_lock; /* protect wr_sends */
	atomic_t cdc_pend_tx_wr; /* number of pending tx CDC wqe
	* - inc when post wqe,
	* - dec on polled tx cqe
	*/
	wait_queue_head_t cdc_pend_tx_wq; /* wakeup on no cdc_pend_tx_wr*/
	struct delayed_work tx_work; /* retry of smc_cdc_msg_send */
	u32 tx_off; /* base offset in peer rmb */

	struct smc_host_cdc_msg local_rx_ctrl; /* filled during event_handl.
	* .prod cf. TCP rcv_nxt
	* .cons cf. TCP snd_una
	*/
	union smc_host_cursor rx_curs_confirmed; /* confirmed to peer
	* source of snd_una ?
	*/
	union smc_host_cursor urg_curs; /* points at urgent byte */
	enum smc_urg_state urg_state;
	bool urg_tx_pend; /* urgent data staged */
	bool urg_rx_skip_pend;
	/* indicate urgent oob data
	* read, but previous regular
	* data still pending
	*/
	char urg_rx_byte; /* urgent byte */
	bool tx_in_release_sock;
	/* flush pending tx data in
	* sock release_cb()
	*/
	atomic_t bytes_to_rcv; /* arrived data,
	* not yet received
	*/
	atomic_t splice_pending; /* number of spliced bytes
	* pending processing
	*/
	#ifndef KERNEL_HAS_ATOMIC64
	spinlock_t acurs_lock; /* protect cursors */
	#endif
	struct work_struct close_work; /* peer sent some closing */
	struct work_struct abort_work; /* abort the connection */
	struct tasklet_struct rx_tsklet; /* Receiver tasklet for SMC-D */
	u8 rx_off; /* receive offset:
	* 0 for SMC-R, 32 for SMC-D
	*/
	u64 peer_token; /* SMC-D token of peer */
	u8 killed : 1; /* abnormal termination */
	u8 freed : 1; /* normal termiation */
	u8 out_of_sync : 1; /* out of sync with peer */
	};

	struct smc_sock { /* smc sock container */
	struct sock sk;
	struct socket clcsock; / internal tcp socket */
	void (clcsk_state_change)(struct sock sk);
	/* original stat_change fct. */
	void (clcsk_data_ready)(struct sock sk);
	/* original data_ready fct. */
	void (clcsk_write_space)(struct sock sk);
	/* original write_space fct. */
	void (clcsk_error_report)(struct sock sk);
	/* original error_report fct. */
	struct smc_connection conn; /* smc connection */
	struct smc_sock listen_smc; / listen parent */
	struct work_struct connect_work; /* handle non-blocking connect*/
	struct work_struct tcp_listen_work;/* handle tcp socket accepts */
	struct work_struct smc_listen_work;/* prepare new accept socket */
	struct list_head accept_q; /* sockets to be accepted */
	spinlock_t accept_q_lock; /* protects accept_q */
	bool limit_smc_hs; /* put constraint on handshake */
	bool use_fallback; /* fallback to tcp */
	int fallback_rsn; /* reason for fallback */
	u32 peer_diagnosis; /* decline reason from peer */
	atomic_t queued_smc_hs; /* queued smc handshakes */
	struct inet_connection_sock_af_ops af_ops;
	const struct inet_connection_sock_af_ops *ori_af_ops;
	/* original af ops */
	int sockopt_defer_accept;
	/* sockopt TCP_DEFER_ACCEPT
	* value
	*/
	u8 wait_close_tx_prepared : 1;
	/* shutdown wr or close
	* started, waiting for unsent
	* data to be sent
	*/
	u8 connect_nonblock : 1;
	/* non-blocking connect in
	* flight
	*/
	struct mutex clcsock_release_lock;
	/* protects clcsock of a listen
	* socket
	* */
	};

	#define smc_sk(ptr) container_of_const(ptr, struct smc_sock, sk)

	static inline void smc_init_saved_callbacks(struct smc_sock *smc)
	{
	smc->clcsk_state_change = NULL;
	smc->clcsk_data_ready = NULL;
	smc->clcsk_write_space = NULL;
	smc->clcsk_error_report = NULL;
	}

	static inline struct smc_sock smc_clcsock_user_data(const struct sock clcsk)
	{
	return (struct smc_sock *)
	((uintptr_t)clcsk->sk_user_data & ~SK_USER_DATA_NOCOPY);
	}

	/* save target_cb in saved_cb, and replace target_cb with new_cb */
	static inline void smc_clcsock_replace_cb(void (*target_cb)(struct sock ),
	void (new_cb)(struct sock ),
	void (*saved_cb)(struct sock ))
	{
	/* only save once */
	if (!*saved_cb)
	saved_cb = target_cb;
	*target_cb = new_cb;
	}

	/* restore target_cb to saved_cb, and reset saved_cb to NULL */
	static inline void smc_clcsock_restore_cb(void (*target_cb)(struct sock ),
	void (*saved_cb)(struct sock ))
	{
	if (!*saved_cb)
	return;
	target_cb = saved_cb;
	*saved_cb = NULL;
	}

	extern struct workqueue_struct smc_hs_wq; / wq for handshake work */
	extern struct workqueue_struct smc_close_wq; / wq for close work */

	#define SMC_SYSTEMID_LEN 8

	extern u8 local_systemid[SMC_SYSTEMID_LEN]; /* unique system identifier */

	#define ntohll(x) be64_to_cpu(x)
	#define htonll(x) cpu_to_be64(x)

	/* convert an u32 value into network byte order, store it into a 3 byte field */
	static inline void hton24(u8 *net, u32 host)
	{
	__be32 t;

	t = cpu_to_be32(host);
	memcpy(net, ((u8 *)&t) + 1, 3);
	}

	/* convert a received 3 byte field into host byte order*/
	static inline u32 ntoh24(u8 *net)
	{
	__be32 t = 0;

	memcpy(((u8 *)&t) + 1, net, 3);
	return be32_to_cpu(t);
	}

	#ifdef CONFIG_XFRM
	static inline bool using_ipsec(struct smc_sock *smc)
	{
	return (smc->clcsock->sk->sk_policy[0] \|\|
	smc->clcsock->sk->sk_policy[1]) ? true : false;
	}
	#else
	static inline bool using_ipsec(struct smc_sock *smc)
	{
	return false;
	}
	#endif

	struct smc_gidlist;

	struct sock smc_accept_dequeue(struct sock parent, struct socket *new_sock);
	void smc_close_non_accepted(struct sock *sk);
	void smc_fill_gid_list(struct smc_link_group *lgr,
	struct smc_gidlist *gidlist,
	struct smc_ib_device known_dev, u8 known_gid);

	/* smc handshake limitation interface for netlink */
	int smc_nl_dump_hs_limitation(struct sk_buff skb, struct netlink_callback cb);
	int smc_nl_enable_hs_limitation(struct sk_buff skb, struct genl_info info);
	int smc_nl_disable_hs_limitation(struct sk_buff skb, struct genl_info info);

	static inline void smc_sock_set_flag(struct sock *sk, enum sock_flags flag)
	{
	set_bit(flag, &sk->sk_flags);
	}

	#endif /* __SMC_H */