[PATCH bpf-next v4 0/4] net/smc: Introduce BPF injection capability

[PATCH bpf-next v4 0/4] net/smc: Introduce BPF injection capability

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This patches attempt to introduce BPF injection capability for SMC,
and add selftest to ensure code stability.

As we all know that the SMC protocol is not suitable for all scenarios,
especially for short-lived. However, for most applications, they cannot
guarantee that there are no such scenarios at all. Therefore, apps
may need some specific strategies to decide shall we need to use SMC
or not, for example, apps can limit the scope of the SMC to a specific
IP address or port.

Based on the consideration of transparent replacement, we hope that apps
can remain transparent even if they need to formulate some specific
strategies for SMC using. That is, do not need to recompile their code.

On the other hand, we need to ensure the scalability of strategies
implementation. Although it is simple to use socket options or sysctl,
it will bring more complexity to subsequent expansion.

Fortunately, BPF can solve these concerns very well, users can write
thire own strategies in eBPF to choose whether to use SMC or not.
And it's quite easy for them to modify their strategies in the future.

This patches implement injection capability for SMC via struct_ops.
In that way, we can add new injection scenarios in the future.

v4 -> v3:
    1. fix compile error and warning

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202302282100.x7qq7PGX-lkp@intel.com/

v3 -> v2:
    1. fix checkpatch error and warning.
    2. split patch for better review.
    3. enhance selftest to cover more scenarios.

v2 -> v1:
    1. fix compile error and warning.

D. Wythe (4):
  net/smc: move smc_sock related structure definition
  bpf: add SMC support in BPF struct_ops
  net/smc: add BPF injection on smc negotiation
  bpf/selftests: add selftest for SMC bpf capability

 include/linux/btf_ids.h                          |  12 +
 include/net/smc.h                                | 263 +++++++++++++++++++
 kernel/bpf/bpf_struct_ops_types.h                |   4 +
 net/Makefile                                     |   5 +
 net/smc/af_smc.c                                 |  15 +-
 net/smc/bpf_smc_struct_ops.c                     | 148 +++++++++++
 net/smc/smc.h                                    | 224 ----------------
 tools/testing/selftests/bpf/prog_tests/bpf_smc.c |  37 +++
 tools/testing/selftests/bpf/progs/bpf_smc.c      | 320 +++++++++++++++++++++++
 9 files changed, 803 insertions(+), 225 deletions(-)
 create mode 100644 net/smc/bpf_smc_struct_ops.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c

-- 
1.8.3.1

[PATCH bpf-next v4 1/4] net/smc: move smc_sock related structure definition

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This patch only try to move the definition of smc_sock and its
related structure, from et/smc/smc.h to include/net/smc/smc.h.
In that way can ebpf generate the BTF ID corresponding to our
structure.

Of course, we can also choose to hide the structure and only to
expose an intermediate structure, but it requires an additional
transformation. If we need to obtain some information frequently, this
may cause some performance problems.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 include/net/smc.h | 225 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 net/smc/smc.h     | 224 -----------------------------------------------------
 2 files changed, 225 insertions(+), 224 deletions(-)

diff --git a/include/net/smc.h b/include/net/smc.h
index 597cb93..eccbd37 100644
--- a/include/net/smc.h
+++ b/include/net/smc.h
@@ -11,12 +11,17 @@
 #ifndef _SMC_H
 #define _SMC_H
 
+#include <net/inet_connection_sock.h>
 #include <linux/device.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/wait.h>
 #include "linux/ism.h"
 
+#ifdef ATOMIC64_INIT
+#define KERNEL_HAS_ATOMIC64
+#endif
+
 struct sock;
 
 #define SMC_MAX_PNETID_LEN	16	/* Max. length of PNET id */
@@ -90,4 +95,224 @@ struct smcd_dev {
 	u8 going_away : 1;
 };
 
+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_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_short;/* 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*/
+	atomic_t		tx_pushing;     /* nr_threads trying tx push */
+	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
+						 */
+};
+
 #endif	/* _SMC_H */
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 5ed765e..6f27f40 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -34,10 +34,6 @@
 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,
@@ -57,232 +53,12 @@ enum smc_state {		/* possible states of an SMC socket */
 
 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_short;/* 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*/
-	atomic_t		tx_pushing;     /* nr_threads trying tx push */
-	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
-						 * */
-};
-
 static inline struct smc_sock *smc_sk(const struct sock *sk)
 {
 	return (struct smc_sock *)sk;
-- 
1.8.3.1

[PATCH bpf-next v4 2/4] bpf: add SMC support in BPF struct_ops

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This PATCH attempts to introduce BPF injection capability for SMC.
Considering that the SMC protocol is not suitable for all scenarios,
especially for short-lived. However, for most applications, they cannot
guarantee that there are no such scenarios at all. Therefore, apps
may need some specific strategies to decide shall we need to use SMC
or not, for example, apps can limit the scope of the SMC to a specific
IP address or port.

Based on the consideration of transparent replacement, we hope that apps
can remain transparent even if they need to formulate some specific
strategies for SMC using. That is, do not need to recompile their code.

On the other hand, we need to ensure the scalability of strategies
implementation. Although it is simple to use socket options or sysctl,
it will bring more complexity to subsequent expansion.

Fortunately, BPF can solve these concerns very well, users can write
thire own strategies in eBPF to choose whether to use SMC or not.
And it's quite easy for them to modify their strategies in the future.

This PATCH implement injection capability for SMC via struct_ops.
In that way, we can add new injection scenarios in the future.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 include/linux/btf_ids.h           |  12 ++++
 include/net/smc.h                 |  38 ++++++++++
 kernel/bpf/bpf_struct_ops_types.h |   4 ++
 net/Makefile                      |   5 ++
 net/smc/bpf_smc_struct_ops.c      | 148 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 207 insertions(+)
 create mode 100644 net/smc/bpf_smc_struct_ops.c

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 3a4f7cd..d4cf0a9 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -264,6 +264,18 @@ enum {
 MAX_BTF_TRACING_TYPE,
 };
 
+#if IS_ENABLED(CONFIG_SMC)
+enum {
+#define BTF_SMC_TYPE(name, type) name,
+BTF_SMC_TYPE(BTF_SMC_TYPE_SOCK, smc_sock)
+BTF_SMC_TYPE(BTF_SMC_TYPE_CONNECTION, smc_connection)
+BTF_SMC_TYPE(BTF_SMC_TYPE_HOST_CURSOR, smc_host_cursor)
+#undef BTF_SMC_TYPE
+MAX_BTF_SMC_TYPE,
+};
+extern u32 btf_smc_ids[];
+#endif
+
 extern u32 btf_tracing_ids[];
 extern u32 bpf_cgroup_btf_id[];
 extern u32 bpf_local_storage_map_btf_id[];
diff --git a/include/net/smc.h b/include/net/smc.h
index eccbd37..1891f49 100644
--- a/include/net/smc.h
+++ b/include/net/smc.h
@@ -16,6 +16,7 @@
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/wait.h>
+#include <linux/bpf.h>
 #include "linux/ism.h"
 
 #ifdef ATOMIC64_INIT
@@ -315,4 +316,41 @@ struct smc_sock {				/* smc sock container */
 						 */
 };
 
+#define SMC_SOCK_CLOSED_TIMING	(0)
+
+#ifdef CONFIG_BPF_SYSCALL
+
+/* BPF struct ops for smc protocol negotiator */
+struct smc_sock_negotiator_ops {
+	/* ret for negotiate */
+	int (*negotiate)(struct smc_sock *sk);
+
+	/* info gathering timing */
+	void (*collect_info)(struct sock *sk, int timing);
+};
+
+/* Query if current sock should go with SMC protocol
+ * SK_PASS for yes, otherwise for no.
+ */
+int smc_sock_should_select_smc(const struct smc_sock *smc);
+
+/* At some specific points in time,
+ * let negotiator can perform info gathering
+ * on target sock.
+ */
+void smc_sock_perform_collecting_info(const struct sock *sk, int timing);
+
+#else
+
+static inline int smc_sock_should_select_smc(const struct smc_sock *smc)
+{
+	return SK_PASS;
+}
+
+static inline void smc_sock_perform_collecting_info(const struct sock *sk, int timing)
+{
+}
+
+#endif /* CONFIG_BPF_SYSCALL */
+
 #endif	/* _SMC_H */
diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
index 5678a9d..35cdd15 100644
--- a/kernel/bpf/bpf_struct_ops_types.h
+++ b/kernel/bpf/bpf_struct_ops_types.h
@@ -9,4 +9,8 @@
 #include <net/tcp.h>
 BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
 #endif
+#if IS_ENABLED(CONFIG_SMC)
+#include <net/smc.h>
+BPF_STRUCT_OPS_TYPE(smc_sock_negotiator_ops)
+#endif
 #endif
diff --git a/net/Makefile b/net/Makefile
index 0914bea..47a4c00 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -52,6 +52,11 @@ obj-$(CONFIG_TIPC)		+= tipc/
 obj-$(CONFIG_NETLABEL)		+= netlabel/
 obj-$(CONFIG_IUCV)		+= iucv/
 obj-$(CONFIG_SMC)		+= smc/
+ifneq ($(CONFIG_SMC),)
+ifeq ($(CONFIG_BPF_SYSCALL),y)
+obj-y				+= smc/bpf_smc_struct_ops.o
+endif
+endif
 obj-$(CONFIG_RFKILL)		+= rfkill/
 obj-$(CONFIG_NET_9P)		+= 9p/
 obj-$(CONFIG_CAIF)		+= caif/
diff --git a/net/smc/bpf_smc_struct_ops.c b/net/smc/bpf_smc_struct_ops.c
new file mode 100644
index 0000000..5772a42
--- /dev/null
+++ b/net/smc/bpf_smc_struct_ops.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/bpf_verifier.h>
+#include <linux/btf_ids.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <net/sock.h>
+#include <net/smc.h>
+
+extern struct bpf_struct_ops smc_sock_negotiator_ops;
+
+DEFINE_RWLOCK(smc_sock_negotiator_ops_rwlock);
+struct smc_sock_negotiator_ops *negotiator;
+
+/* convert sk to smc_sock */
+static inline struct smc_sock *smc_sk(const struct sock *sk)
+{
+	return (struct smc_sock *)sk;
+}
+
+/* register ops */
+static inline void smc_reg_passive_sk_ops(struct smc_sock_negotiator_ops *ops)
+{
+	write_lock_bh(&smc_sock_negotiator_ops_rwlock);
+	negotiator = ops;
+	write_unlock_bh(&smc_sock_negotiator_ops_rwlock);
+}
+
+/* unregister ops */
+static inline void smc_unreg_passive_sk_ops(struct smc_sock_negotiator_ops *ops)
+{
+	write_lock_bh(&smc_sock_negotiator_ops_rwlock);
+	if (negotiator == ops)
+		negotiator = NULL;
+	write_unlock_bh(&smc_sock_negotiator_ops_rwlock);
+}
+
+int smc_sock_should_select_smc(const struct smc_sock *smc)
+{
+	int ret = SK_PASS;
+
+	read_lock_bh(&smc_sock_negotiator_ops_rwlock);
+	if (negotiator && negotiator->negotiate)
+		ret = negotiator->negotiate((struct smc_sock *)smc);
+	read_unlock_bh(&smc_sock_negotiator_ops_rwlock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(smc_sock_should_select_smc);
+
+void smc_sock_perform_collecting_info(const struct sock *sk, int timing)
+{
+	read_lock_bh(&smc_sock_negotiator_ops_rwlock);
+	if (negotiator && negotiator->collect_info)
+		negotiator->collect_info((struct sock *)sk, timing);
+	read_unlock_bh(&smc_sock_negotiator_ops_rwlock);
+}
+EXPORT_SYMBOL_GPL(smc_sock_perform_collecting_info);
+
+/* define global smc ID for smc_struct_ops */
+BTF_ID_LIST_GLOBAL(btf_smc_ids, MAX_BTF_SMC_TYPE)
+#define BTF_SMC_TYPE(name, type) BTF_ID(struct, type)
+BTF_SMC_TYPE(BTF_SMC_TYPE_SOCK, smc_sock)
+BTF_SMC_TYPE(BTF_SMC_TYPE_CONNECTION, smc_connection)
+BTF_SMC_TYPE(BTF_SMC_TYPE_HOST_CURSOR, smc_host_cursor)
+#undef BTF_SMC_TYPE
+
+static int bpf_smc_passive_sk_init(struct btf *btf)
+{
+	return 0;
+}
+
+/* register ops by BPF */
+static int bpf_smc_passive_sk_ops_reg(void *kdata)
+{
+	struct smc_sock_negotiator_ops *ops = kdata;
+
+	/* at least one ops need implement */
+	if (!ops->negotiate || !ops->collect_info) {
+		pr_err("At least one ops need implement.\n");
+		return -EINVAL;
+	}
+
+	smc_reg_passive_sk_ops(ops);
+	/* always success now */
+	return 0;
+}
+
+/* unregister ops by BPF */
+static void bpf_smc_passive_sk_ops_unreg(void *kdata)
+{
+	smc_unreg_passive_sk_ops(kdata);
+}
+
+static int bpf_smc_passive_sk_ops_check_member(const struct btf_type *t,
+					       const struct btf_member *member,
+					       const struct bpf_prog *prog)
+{
+	return 0;
+}
+
+static int bpf_smc_passive_sk_ops_init_member(const struct btf_type *t,
+					      const struct btf_member *member,
+					      void *kdata, const void *udata)
+{
+	return 0;
+}
+
+static const struct bpf_func_proto *
+smc_passive_sk_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	return bpf_base_func_proto(func_id);
+}
+
+static bool smc_passive_sk_ops_prog_is_valid_access(int off, int size, enum bpf_access_type type,
+						    const struct bpf_prog *prog,
+						    struct bpf_insn_access_aux *info)
+{
+	return bpf_tracing_btf_ctx_access(off, size, type, prog, info);
+}
+
+static int smc_passive_sk_ops_prog_struct_access(struct bpf_verifier_log *log,
+						 const struct bpf_reg_state *reg,
+						 int off, int size, enum bpf_access_type atype,
+						 u32 *next_btf_id, enum bpf_type_flag *flag)
+{
+	/* only allow read now*/
+	if (atype == BPF_READ)
+		return btf_struct_access(log, reg, off, size, atype, next_btf_id, flag);
+
+	return -EACCES;
+}
+
+static const struct bpf_verifier_ops bpf_smc_passive_sk_verifier_ops = {
+	.get_func_proto  = smc_passive_sk_prog_func_proto,
+	.is_valid_access = smc_passive_sk_ops_prog_is_valid_access,
+	.btf_struct_access = smc_passive_sk_ops_prog_struct_access
+};
+
+struct bpf_struct_ops bpf_smc_sock_negotiator_ops = {
+	.verifier_ops = &bpf_smc_passive_sk_verifier_ops,
+	.init = bpf_smc_passive_sk_init,
+	.check_member = bpf_smc_passive_sk_ops_check_member,
+	.init_member = bpf_smc_passive_sk_ops_init_member,
+	.reg = bpf_smc_passive_sk_ops_reg,
+	.unreg = bpf_smc_passive_sk_ops_unreg,
+	.name = "smc_sock_negotiator_ops",
+};
-- 
1.8.3.1

[PATCH bpf-next v4 3/4] net/smc: add BPF injection on smc negotiation

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This patch try add BPF injection on smc negotiation, so that
the application can decided whether to use smc or not through
eBPF progs.

In particular, some applications may need global dynamic information
to make decision. Therefore, we also inject a information collect
point into smc_release.

Note that, in order to make negotiation can be decided by application,
sockets must have SMC_LIMIT_HS set.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 net/smc/af_smc.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index a4cccdf..7ebe5e8 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -166,6 +166,9 @@ static bool smc_hs_congested(const struct sock *sk)
 	if (workqueue_congested(WORK_CPU_UNBOUND, smc_hs_wq))
 		return true;
 
+	if (!smc_sock_should_select_smc(smc))
+		return true;
+
 	return false;
 }
 
@@ -320,6 +323,9 @@ static int smc_release(struct socket *sock)
 	sock_hold(sk); /* sock_put below */
 	smc = smc_sk(sk);
 
+	/* trigger info gathering if needed.*/
+	smc_sock_perform_collecting_info(sk, SMC_SOCK_CLOSED_TIMING);
+
 	old_state = sk->sk_state;
 
 	/* cleanup for a dangling non-blocking connect */
@@ -1627,7 +1633,14 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr,
 	}
 
 	smc_copy_sock_settings_to_clc(smc);
-	tcp_sk(smc->clcsock->sk)->syn_smc = 1;
+	/* accept out connection as SMC connection */
+	if (smc_sock_should_select_smc(smc) == SK_PASS) {
+		tcp_sk(smc->clcsock->sk)->syn_smc = 1;
+	} else {
+		tcp_sk(smc->clcsock->sk)->syn_smc = 0;
+		smc_switch_to_fallback(smc, /* just a chooice */ 0);
+	}
+
 	if (smc->connect_nonblock) {
 		rc = -EALREADY;
 		goto out;
-- 
1.8.3.1

[PATCH bpf-next v4 4/4] bpf/selftests: add selftest for SMC bpf capability

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This PATCH adds a tiny selftest for SMC bpf capability,
making decisions on whether to use SMC by collecting
certain information from kernel smc sock.

Follow the steps below to run this test.

make -C tools/testing/selftests/bpf
cd tools/testing/selftests/bpf
sudo ./test_progs -t bpf_smc

Results shows:
18      bpf_smc:OK
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 tools/testing/selftests/bpf/prog_tests/bpf_smc.c |  37 +++
 tools/testing/selftests/bpf/progs/bpf_smc.c      | 320 +++++++++++++++++++++++
 2 files changed, 357 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_smc.c b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c
new file mode 100644
index 0000000..b57326c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/err.h>
+#include <netinet/tcp.h>
+#include <test_progs.h>
+#include "bpf_smc.skel.h"
+
+void test_bpf_smc(void)
+{
+	struct bpf_smc *smc_skel;
+	struct bpf_link *link;
+	int err;
+
+	smc_skel = bpf_smc__open();
+	if (!ASSERT_OK_PTR(smc_skel, "skel_open"))
+		return;
+
+	err = bpf_map__set_type(smc_skel->maps.negotiator_map, BPF_MAP_TYPE_HASH);
+	if (!ASSERT_OK(err, "bpf_map__set_type"))
+		goto error;
+
+	err = bpf_map__set_max_entries(smc_skel->maps.negotiator_map, 1);
+	if (!ASSERT_OK(err, "bpf_map__set_type"))
+		goto error;
+
+	err =  bpf_smc__load(smc_skel);
+	if (!ASSERT_OK(err, "skel_load"))
+		goto error;
+
+	link = bpf_map__attach_struct_ops(smc_skel->maps.ops);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops"))
+		goto error;
+
+	bpf_link__destroy(link);
+error:
+	bpf_smc__destroy(smc_skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/bpf_smc.c b/tools/testing/selftests/bpf/progs/bpf_smc.c
new file mode 100644
index 0000000..4f4a541
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_smc.c
@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bpf.h>
+#include <linux/stddef.h>
+#include <linux/smc.h>
+#include <stdbool.h>
+#include <linux/types.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+
+#define AF_SMC			(43)
+#define SMC_LISTEN		(10)
+#define SMC_SOCK_CLOSED_TIMING	(0)
+extern unsigned long CONFIG_HZ __kconfig;
+#define HZ CONFIG_HZ
+
+char _license[] SEC("license") = "GPL";
+#define max(a, b) ((a) > (b) ? (a) : (b))
+
+struct sock_common {
+	unsigned char	skc_state;
+	unsigned short	skc_family;
+	__u16	skc_num;
+} __attribute__((preserve_access_index));
+
+struct sock {
+	struct sock_common	__sk_common;
+	int	sk_sndbuf;
+} __attribute__((preserve_access_index));
+
+struct inet_sock {
+	struct sock	sk;
+} __attribute__((preserve_access_index));
+
+struct inet_connection_sock {
+	struct inet_sock	icsk_inet;
+} __attribute__((preserve_access_index));
+
+struct tcp_sock {
+	struct inet_connection_sock	inet_conn;
+	__u32	rcv_nxt;
+	__u32	snd_nxt;
+	__u32	snd_una;
+	__u32	delivered;
+	__u8	syn_data:1,	/* SYN includes data */
+		syn_fastopen:1,	/* SYN includes Fast Open option */
+		syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
+		syn_fastopen_ch:1, /* Active TFO re-enabling probe */
+		syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
+		save_syn:1,	/* Save headers of SYN packet */
+		is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */
+		syn_smc:1;	/* SYN includes SMC */
+} __attribute__((preserve_access_index));
+
+struct socket {
+	struct sock *sk;
+} __attribute__((preserve_access_index));
+
+union smc_host_cursor {
+	struct {
+		__u16	reserved;
+		__u16	wrap;
+		__u32	count;
+	};
+} __attribute__((preserve_access_index));
+
+struct smc_connection {
+	union smc_host_cursor	tx_curs_sent;
+	union smc_host_cursor	rx_curs_confirmed;
+} __attribute__((preserve_access_index));
+
+struct smc_sock {
+	struct sock	sk;
+	struct socket	*clcsock;	/* internal tcp socket */
+	struct smc_connection	conn;
+	int use_fallback;
+} __attribute__((preserve_access_index));
+
+static __always_inline struct tcp_sock *tcp_sk(const struct sock *sk)
+{
+	return (struct tcp_sock *)sk;
+}
+
+static __always_inline struct smc_sock *smc_sk(struct sock *sk)
+{
+	return (struct smc_sock *)sk;
+}
+
+struct smc_prediction {
+	/* protection for smc_prediction */
+	struct bpf_spin_lock lock;
+	/* start of time slice */
+	__u64	start_tstamp;
+	/* delta of pacing */
+	__u64	pacing_delta;
+	/* N of closed connections determined as long connections
+	 * in current time slice
+	 */
+	__u32	closed_long_cc;
+	/* N of closed connections in this time slice */
+	__u32	closed_total_cc;
+	/* N of incoming connections determined as long connections
+	 * in current time slice
+	 */
+	__u32	incoming_long_cc;
+	/* last splice rate of long cc */
+	__u32	last_rate_of_lcc;
+};
+
+#define SMC_PREDICTION_MIN_PACING_DELTA                (1llu)
+#define SMC_PREDICTION_MAX_PACING_DELTA                (HZ << 3)
+#define SMC_PREDICTION_MAX_LONGCC_PER_SPLICE           (8)
+#define SMC_PREDICTION_MAX_PORT                        (64)
+#define SMC_PREDICTION_MAX_SPLICE_GAP                  (1)
+#define SMC_PREDICTION_LONGCC_RATE_THRESHOLD           (13189)
+#define SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD        (100)
+#define SMC_PREDICTION_LONGCC_BYTES_THRESHOLD	\
+		(SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD * 1024)
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(max_entries, SMC_PREDICTION_MAX_PORT);
+	__type(key, __u16);
+	__type(value, struct smc_prediction);
+} negotiator_map SEC(".maps");
+
+
+static inline __u32 smc_prediction_calt_rate(struct smc_prediction *smc_predictor)
+{
+	if (!smc_predictor->closed_total_cc)
+		return smc_predictor->last_rate_of_lcc;
+
+	return (smc_predictor->closed_long_cc << 14) / smc_predictor->closed_total_cc;
+}
+
+static inline struct smc_prediction *smc_prediction_get(__u16 key, __u64 tstamp)
+{
+	struct smc_prediction zero = {}, *smc_predictor;
+	__u32 gap;
+	int err;
+
+	smc_predictor = bpf_map_lookup_elem(&negotiator_map, &key);
+	if (!smc_predictor) {
+		zero.start_tstamp = bpf_jiffies64();
+		zero.pacing_delta = SMC_PREDICTION_MIN_PACING_DELTA;
+		err = bpf_map_update_elem(&negotiator_map, &key, &zero, 0);
+		if (err)
+			return NULL;
+		smc_predictor =  bpf_map_lookup_elem(&negotiator_map, &key);
+		if (!smc_predictor)
+			return NULL;
+	}
+
+	if (tstamp) {
+		bpf_spin_lock(&smc_predictor->lock);
+		gap = (tstamp - smc_predictor->start_tstamp) / smc_predictor->pacing_delta;
+		/* new splice */
+		if (gap > 0) {
+			smc_predictor->start_tstamp = tstamp;
+			smc_predictor->last_rate_of_lcc =
+				(smc_prediction_calt_rate(smc_predictor) * 7) >> (2 + gap);
+			smc_predictor->closed_long_cc = 0;
+			smc_predictor->closed_total_cc = 0;
+			smc_predictor->incoming_long_cc = 0;
+		}
+		bpf_spin_unlock(&smc_predictor->lock);
+	}
+	return smc_predictor;
+}
+
+/* BPF struct ops for smc protocol negotiator */
+struct smc_sock_negotiator_ops {
+	/* ret for negotiate */
+	int (*negotiate)(struct smc_sock *smc);
+
+	/* info gathering timing */
+	void (*collect_info)(struct smc_sock *smc, int timing);
+};
+
+int SEC("struct_ops/bpf_smc_negotiate")
+BPF_PROG(bpf_smc_negotiate, struct smc_sock *smc)
+{
+	struct smc_prediction *smc_predictor;
+	int err, ret = SK_DROP;
+	struct tcp_sock *tp;
+	struct sock *clcsk;
+	__u32 rate = 0;
+	__u16 key;
+
+	/* client side */
+	if (smc == NULL || smc->sk.__sk_common.skc_state != SMC_LISTEN) {
+		/* use Global smc_predictor */
+		key = 0;
+	} else {	/* server side */
+		clcsk = BPF_CORE_READ(smc, clcsock, sk);
+		if (!clcsk)
+			goto error;
+		tp = tcp_sk(clcsk);
+		err = bpf_core_read(&key, sizeof(__u16),
+				    &tp->inet_conn.icsk_inet.sk.__sk_common.skc_num);
+		if (err)
+			goto error;
+	}
+
+	smc_predictor = smc_prediction_get(key, bpf_jiffies64());
+	if (!smc_predictor)
+		return SK_PASS;
+
+	bpf_spin_lock(&smc_predictor->lock);
+
+	if (smc_predictor->incoming_long_cc == 0)
+		goto out_locked_pass;
+
+	if (smc_predictor->incoming_long_cc > SMC_PREDICTION_MAX_LONGCC_PER_SPLICE)
+		goto out_locked_drop;
+
+	rate = smc_prediction_calt_rate(smc_predictor);
+	if (rate < SMC_PREDICTION_LONGCC_RATE_THRESHOLD)
+		goto out_locked_drop;
+
+out_locked_pass:
+	smc_predictor->incoming_long_cc++;
+	bpf_spin_unlock(&smc_predictor->lock);
+	return SK_PASS;
+out_locked_drop:
+	bpf_spin_unlock(&smc_predictor->lock);
+error:
+	return SK_DROP;
+}
+
+void SEC("struct_ops/bpf_smc_collect_info")
+BPF_PROG(bpf_smc_collect_info, struct sock *sk, int timing)
+{
+	struct smc_prediction *smc_predictor;
+	int use_fallback, sndbuf, err;
+	struct smc_sock *smc;
+	struct tcp_sock *tp;
+	struct sock *clcsk;
+	bool match = false;
+	__u16 wrap, count;
+	__u32 delivered;
+	__u16 key;
+
+	/* no info can collect */
+	if (sk == NULL)
+		return;
+
+	/* only fouces on closed */
+	if (timing != SMC_SOCK_CLOSED_TIMING)
+		return;
+
+	/* first check the sk type */
+	if (sk->__sk_common.skc_family == AF_SMC) {
+		smc = smc_sk(sk);
+		clcsk = BPF_CORE_READ(smc, clcsock, sk);
+		if (!clcsk)
+			goto error;
+		tp = tcp_sk(clcsk);
+		/* check if it's fallback */
+		err = bpf_core_read(&use_fallback, sizeof(use_fallback), &smc->use_fallback);
+		if (err)
+			goto error;
+		if (use_fallback)
+			goto fallback;
+		err = bpf_core_read(&wrap, sizeof(__u16), &smc->conn.tx_curs_sent.wrap);
+		if (err)
+			goto error;
+		err = bpf_core_read(&count, sizeof(__u16), &smc->conn.tx_curs_sent.count);
+		if (err)
+			goto error;
+		err = bpf_core_read(&sndbuf, sizeof(int), &clcsk->sk_sndbuf);
+		if (err)
+			goto error;
+		 match = (count + wrap * sndbuf) > SMC_PREDICTION_LONGCC_BYTES_THRESHOLD;
+	} else {
+		smc = NULL;
+		tp = tcp_sk(sk);
+		use_fallback = 1;
+fallback:
+		err = bpf_core_read(&delivered, sizeof(delivered), &tp->delivered);
+		if (err)
+			goto error;
+		match = (delivered > SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD);
+	}
+
+	/* whatever, tp is never NULL */
+	err = bpf_core_read(&key, sizeof(__u16), &tp->inet_conn.icsk_inet.sk.__sk_common.skc_num);
+	if (err)
+		goto error;
+
+	smc_predictor = smc_prediction_get(key, 0);
+	if (!smc_predictor)
+		goto error;
+
+	bpf_spin_lock(&smc_predictor->lock);
+	smc_predictor->closed_total_cc++;
+	if (match) {
+		/* increase stats */
+		smc_predictor->closed_long_cc++;
+		/* try more aggressive */
+		if (smc_predictor->pacing_delta > SMC_PREDICTION_MIN_PACING_DELTA) {
+			if (use_fallback) {
+				smc_predictor->pacing_delta = max(SMC_PREDICTION_MIN_PACING_DELTA,
+						(smc_predictor->pacing_delta * 3) >> 2);
+			}
+		}
+	} else if (!use_fallback) {
+		smc_predictor->pacing_delta <<= 1;
+	}
+	bpf_spin_unlock(&smc_predictor->lock);
+error:
+	return;
+}
+
+SEC(".struct_ops")
+struct smc_sock_negotiator_ops ops = {
+	.negotiate	= (void *)bpf_smc_negotiate,
+	.collect_info	= (void *)bpf_smc_collect_info,
+};
-- 
1.8.3.1

Re: [PATCH bpf-next v4 0/4] net/smc: Introduce BPF injection capability

[Jakub Kicinski]

On Wed,  1 Mar 2023 00:38:07 +0800 D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
> 
> This patches attempt to introduce BPF injection capability for SMC,
> and add selftest to ensure code stability.

If you cross-posting to net please make sure you follow netdev rules.
Don't repost too often.

Re: [PATCH bpf-next v4 0/4] net/smc: Introduce BPF injection capability

[D. Wythe]

On 3/1/23 7:02 AM, Jakub Kicinski wrote:
> On Wed,  1 Mar 2023 00:38:07 +0800 D. Wythe wrote:
>> From: "D. Wythe" <alibuda@linux.alibaba.com>
>>
>> This patches attempt to introduce BPF injection capability for SMC,
>> and add selftest to ensure code stability.
> 
> If you cross-posting to net please make sure you follow netdev rules.
> Don't repost too often.

I'm very sorry, dues to some low-level errors,
so I was anxious to fix such problems.

I will pay more attention in the future!! Thanks for
your advice.

best wishes
D. Wythe

Re: [PATCH bpf-next v4 0/4] net/smc: Introduce BPF injection capability

[D. Wythe]

On 3/1/23 12:38 AM, D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
>
> This patches attempt to introduce BPF injection capability for SMC,
> and add selftest to ensure code stability.
>
> As we all know that the SMC protocol is not suitable for all scenarios,
> especially for short-lived. However, for most applications, they cannot
> guarantee that there are no such scenarios at all. Therefore, apps
> may need some specific strategies to decide shall we need to use SMC
> or not, for example, apps can limit the scope of the SMC to a specific
> IP address or port.
>
> Based on the consideration of transparent replacement, we hope that apps
> can remain transparent even if they need to formulate some specific
> strategies for SMC using. That is, do not need to recompile their code.
>
> On the other hand, we need to ensure the scalability of strategies
> implementation. Although it is simple to use socket options or sysctl,
> it will bring more complexity to subsequent expansion.
>
> Fortunately, BPF can solve these concerns very well, users can write
> thire own strategies in eBPF to choose whether to use SMC or not.
> And it's quite easy for them to modify their strategies in the future.
>
> This patches implement injection capability for SMC via struct_ops.
> In that way, we can add new injection scenarios in the future.
>
> v4 -> v3:
>      1. fix compile error and warning
>
> Reported-by: kernel test robot <lkp@intel.com>
> Link: https://lore.kernel.org/oe-kbuild-all/202302282100.x7qq7PGX-lkp@intel.com/

Hi Wenjia and all,

I wondering if there are any more questions about this PATCH, This patch 
seems to have been hanging for some time.

If you have any questions, please let me know.


Thanks,

D. Wythe


Do you have any questions about this PATCH?  If you have any other 
questions, please let me know.

Re: [PATCH bpf-next v4 0/4] net/smc: Introduce BPF injection capability

[Martin KaFai Lau]

On 3/6/23 7:05 PM, D. Wythe wrote:
> I wondering if there are any more questions about this PATCH, This patch seems 
May be start with the questions on v2 first.

> to have been hanging for some time.
> 
> If you have any questions, please let me know.
> 
> 
> Thanks,
> 
> D. Wythe
> 
> 
> Do you have any questions about this PATCH?  If you have any other questions, 
> please let me know.
> 

Re: [PATCH bpf-next v4 0/4] net/smc: Introduce BPF injection capability

[D. Wythe]

Hi Martin

I'm very sorry to see your comments on v2  just now...

I just checked the email and found that your reply was filtered out by 
my email terminal. 😭

Thank you very much for your comments. I will try to modify it according 
to your suggestions.

Best wishes.

D. Wythe


On 3/8/23 12:44 AM, Martin KaFai Lau wrote:
> On 3/6/23 7:05 PM, D. Wythe wrote:
>> I wondering if there are any more questions about this PATCH, This 
>> patch seems 
> May be start with the questions on v2 first.
>
>> to have been hanging for some time.
>>
>> If you have any questions, please let me know.
>>
>>
>> Thanks,
>>
>> D. Wythe
>>
>>
>> Do you have any questions about this PATCH?  If you have any other 
>> questions, please let me know.
>>

Re: [PATCH bpf-next v4 1/4] net/smc: move smc_sock related structure definition

[Tony Lu]

On Wed, Mar 01, 2023 at 12:38:08AM +0800, D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
> 
> This patch only try to move the definition of smc_sock and its
> related structure, from et/smc/smc.h to include/net/smc/smc.h.
> In that way can ebpf generate the BTF ID corresponding to our
> structure.
> 
> Of course, we can also choose to hide the structure and only to
> expose an intermediate structure, but it requires an additional
> transformation. If we need to obtain some information frequently, this
> may cause some performance problems.
> 
> Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
> ---
>  include/net/smc.h | 225 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  net/smc/smc.h     | 224 -----------------------------------------------------
>  2 files changed, 225 insertions(+), 224 deletions(-)

This change reminds me that should we add these files into MAINTAINERS
file?

Currently, only net/smc listed in the file. 

SHARED MEMORY COMMUNICATIONS (SMC) SOCKETS
M:  Karsten Graul <kgraul@linux.ibm.com>
M:  Wenjia Zhang <wenjia@linux.ibm.com>
M:  Jan Karcher <jaka@linux.ibm.com>
L:  linux-s390@vger.kernel.org
S:  Supported
F:  net/smc/

These files are out of MAINTAINERS file, get_maintainer.pl script
doesn't work.

include/net/smc.h
include/net/netns/smc.h
include/uapi/linux/smc_diag.h
include/uapi/linux/smc.h

Thanks,
Tony Lu

> 
> diff --git a/include/net/smc.h b/include/net/smc.h
> index 597cb93..eccbd37 100644
> --- a/include/net/smc.h
> +++ b/include/net/smc.h
> @@ -11,12 +11,17 @@
>  #ifndef _SMC_H
>  #define _SMC_H
>  
> +#include <net/inet_connection_sock.h>
>  #include <linux/device.h>
>  #include <linux/spinlock.h>
>  #include <linux/types.h>
>  #include <linux/wait.h>
>  #include "linux/ism.h"
>  
> +#ifdef ATOMIC64_INIT
> +#define KERNEL_HAS_ATOMIC64
> +#endif
> +
>  struct sock;
>  
>  #define SMC_MAX_PNETID_LEN	16	/* Max. length of PNET id */
> @@ -90,4 +95,224 @@ struct smcd_dev {
>  	u8 going_away : 1;
>  };
>  
> +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_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_short;/* 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*/
> +	atomic_t		tx_pushing;     /* nr_threads trying tx push */
> +	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
> +						 */
> +};
> +
>  #endif	/* _SMC_H */
> diff --git a/net/smc/smc.h b/net/smc/smc.h
> index 5ed765e..6f27f40 100644
> --- a/net/smc/smc.h
> +++ b/net/smc/smc.h
> @@ -34,10 +34,6 @@
>  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,
> @@ -57,232 +53,12 @@ enum smc_state {		/* possible states of an SMC socket */
>  
>  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_short;/* 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*/
> -	atomic_t		tx_pushing;     /* nr_threads trying tx push */
> -	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
> -						 * */
> -};
> -
>  static inline struct smc_sock *smc_sk(const struct sock *sk)
>  {
>  	return (struct smc_sock *)sk;
> -- 
> 1.8.3.1