smc_core.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 *  Definitions for SMC Connections, Link Groups and Links
 *
 *  Copyright IBM Corp. 2016
 *
 *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#ifndef _SMC_CORE_H
#define _SMC_CORE_H

#include <linux/atomic.h>
#include <rdma/ib_verbs.h>

#include "smc.h"
#include "smc_ib.h"

#define SMC_RMBS_PER_LGR_MAX	255	/* max. # of RMBs per link group */

struct smc_lgr_list {			/* list of link group definition */
	struct list_head	list;
	spinlock_t		lock;	/* protects list of link groups */
	u32			num;	/* unique link group number */
};

enum smc_lgr_role {		/* possible roles of a link group */
	SMC_CLNT,	/* client */
	SMC_SERV	/* server */
};

enum smc_link_state {			/* possible states of a link */
	SMC_LNK_UNUSED,		/* link is unused */
	SMC_LNK_INACTIVE,	/* link is inactive */
	SMC_LNK_ACTIVATING,	/* link is being activated */
	SMC_LNK_ACTIVE,		/* link is active */
	SMC_LNK_DELETING,	/* link is being deleted */
};

#define SMC_WR_BUF_SIZE		48	/* size of work request buffer */

struct smc_wr_buf {
	u8	raw[SMC_WR_BUF_SIZE];
};

#define SMC_WR_REG_MR_WAIT_TIME	(5 * HZ)/* wait time for ib_wr_reg_mr result */

enum smc_wr_reg_state {
	POSTED,		/* ib_wr_reg_mr request posted */
	CONFIRMED,	/* ib_wr_reg_mr response: successful */
	FAILED		/* ib_wr_reg_mr response: failure */
};

struct smc_rdma_sge {				/* sges for RDMA writes */
	struct ib_sge		wr_tx_rdma_sge[SMC_IB_MAX_SEND_SGE];
};

#define SMC_MAX_RDMA_WRITES	2		/* max. # of RDMA writes per
						 * message send
						 */

struct smc_rdma_sges {				/* sges per message send */
	struct smc_rdma_sge	tx_rdma_sge[SMC_MAX_RDMA_WRITES];
};

struct smc_rdma_wr {				/* work requests per message
						 * send
						 */
	struct ib_rdma_wr	wr_tx_rdma[SMC_MAX_RDMA_WRITES];
};

struct smc_link {
	struct smc_ib_device	*smcibdev;	/* ib-device */
	u8			ibport;		/* port - values 1 | 2 */
	struct ib_pd		*roce_pd;	/* IB protection domain,
						 * unique for every RoCE QP
						 */
	struct ib_qp		*roce_qp;	/* IB queue pair */
	struct ib_qp_attr	qp_attr;	/* IB queue pair attributes */

	struct smc_wr_buf	*wr_tx_bufs;	/* WR send payload buffers */
	struct ib_send_wr	*wr_tx_ibs;	/* WR send meta data */
	struct ib_sge		*wr_tx_sges;	/* WR send gather meta data */
	struct smc_rdma_sges	*wr_tx_rdma_sges;/*RDMA WRITE gather meta data*/
	struct smc_rdma_wr	*wr_tx_rdmas;	/* WR RDMA WRITE */
	struct smc_wr_tx_pend	*wr_tx_pends;	/* WR send waiting for CQE */
	/* above four vectors have wr_tx_cnt elements and use the same index */
	dma_addr_t		wr_tx_dma_addr;	/* DMA address of wr_tx_bufs */
	atomic_long_t		wr_tx_id;	/* seq # of last sent WR */
	unsigned long		*wr_tx_mask;	/* bit mask of used indexes */
	u32			wr_tx_cnt;	/* number of WR send buffers */
	wait_queue_head_t	wr_tx_wait;	/* wait for free WR send buf */

	struct smc_wr_buf	*wr_rx_bufs;	/* WR recv payload buffers */
	struct ib_recv_wr	*wr_rx_ibs;	/* WR recv meta data */
	struct ib_sge		*wr_rx_sges;	/* WR recv scatter meta data */
	/* above three vectors have wr_rx_cnt elements and use the same index */
	dma_addr_t		wr_rx_dma_addr;	/* DMA address of wr_rx_bufs */
	u64			wr_rx_id;	/* seq # of last recv WR */
	u32			wr_rx_cnt;	/* number of WR recv buffers */
	unsigned long		wr_rx_tstamp;	/* jiffies when last buf rx */

	struct ib_reg_wr	wr_reg;		/* WR register memory region */
	wait_queue_head_t	wr_reg_wait;	/* wait for wr_reg result */
	enum smc_wr_reg_state	wr_reg_state;	/* state of wr_reg request */

	u8			gid[SMC_GID_SIZE];/* gid matching used vlan id*/
	u8			sgid_index;	/* gid index for vlan id      */
	u32			peer_qpn;	/* QP number of peer */
	enum ib_mtu		path_mtu;	/* used mtu */
	enum ib_mtu		peer_mtu;	/* mtu size of peer */
	u32			psn_initial;	/* QP tx initial packet seqno */
	u32			peer_psn;	/* QP rx initial packet seqno */
	u8			peer_mac[ETH_ALEN];	/* = gid[8:10||13:15] */
	u8			peer_gid[SMC_GID_SIZE];	/* gid of peer*/
	u8			link_id;	/* unique # within link group */
	u8			link_idx;	/* index in lgr link array */
	struct smc_link_group	*lgr;		/* parent link group */

	enum smc_link_state	state;		/* state of link */
	struct completion	llc_confirm;	/* wait for rx of conf link */
	struct completion	llc_confirm_resp; /* wait 4 rx of cnf lnk rsp */
	int			llc_confirm_rc; /* rc from confirm link msg */
	int			llc_confirm_resp_rc; /* rc from conf_resp msg */
	struct completion	llc_add;	/* wait for rx of add link */
	struct completion	llc_add_resp;	/* wait for rx of add link rsp*/
	struct delayed_work	llc_testlink_wrk; /* testlink worker */
	struct completion	llc_testlink_resp; /* wait for rx of testlink */
	int			llc_testlink_time; /* testlink interval */
	struct completion	llc_confirm_rkey_resp; /* w4 rx of cnf rkey */
	int			llc_confirm_rkey_resp_rc; /* rc from cnf rkey */
	struct completion	llc_delete_rkey_resp; /* w4 rx of del rkey */
	int			llc_delete_rkey_resp_rc; /* rc from del rkey */
	struct mutex		llc_delete_rkey_mutex; /* serialize usage */
};

/* For now we just allow one parallel link per link group. The SMC protocol
 * allows more (up to 8).
 */
#define SMC_LINKS_PER_LGR_MAX	1
#define SMC_SINGLE_LINK		0

#define SMC_FIRST_CONTACT	1		/* first contact to a peer */
#define SMC_REUSE_CONTACT	0		/* follow-on contact to a peer*/

/* tx/rx buffer list element for sndbufs list and rmbs list of a lgr */
struct smc_buf_desc {
	struct list_head	list;
	void			*cpu_addr;	/* virtual address of buffer */
	struct page		*pages;
	int			len;		/* length of buffer */
	u32			used;		/* currently used / unused */
	union {
		struct { /* SMC-R */
			struct sg_table	sgt[SMC_LINKS_PER_LGR_MAX];
					/* virtual buffer */
			struct ib_mr	*mr_rx[SMC_LINKS_PER_LGR_MAX];
					/* for rmb only: memory region
					 * incl. rkey provided to peer
					 */
			u32		order;	/* allocation order */

			u8		is_conf_rkey;
					/* confirm_rkey done */
			u8		is_reg_mr[SMC_LINKS_PER_LGR_MAX];
					/* mem region registered */
			u8		is_map_ib[SMC_LINKS_PER_LGR_MAX];
					/* mem region mapped to lnk */
			u8		is_reg_err;
					/* buffer registration err */
		};
		struct { /* SMC-D */
			unsigned short	sba_idx;
					/* SBA index number */
			u64		token;
					/* DMB token number */
			dma_addr_t	dma_addr;
					/* DMA address */
		};
	};
};

struct smc_rtoken {				/* address/key of remote RMB */
	u64			dma_addr;
	u32			rkey;
};

#define SMC_LGR_ID_SIZE		4
#define SMC_BUF_MIN_SIZE	16384	/* minimum size of an RMB */
#define SMC_RMBE_SIZES		16	/* number of distinct RMBE sizes */
/* theoretically, the RFC states that largest size would be 512K,
 * i.e. compressed 5 and thus 6 sizes (0..5), despite
 * struct smc_clc_msg_accept_confirm.rmbe_size being a 4 bit value (0..15)
 */

struct smcd_dev;

struct smc_link_group {
	struct list_head	list;
	struct rb_root		conns_all;	/* connection tree */
	rwlock_t		conns_lock;	/* protects conns_all */
	unsigned int		conns_num;	/* current # of connections */
	unsigned short		vlan_id;	/* vlan id of link group */

	struct list_head	sndbufs[SMC_RMBE_SIZES];/* tx buffers */
	struct mutex		sndbufs_lock;	/* protects tx buffers */
	struct list_head	rmbs[SMC_RMBE_SIZES];	/* rx buffers */
	struct mutex		rmbs_lock;	/* protects rx buffers */

	u8			id[SMC_LGR_ID_SIZE];	/* unique lgr id */
	struct delayed_work	free_work;	/* delayed freeing of an lgr */
	struct work_struct	terminate_work;	/* abnormal lgr termination */
	u8			sync_err : 1;	/* lgr no longer fits to peer */
	u8			terminating : 1;/* lgr is terminating */
	u8			freefast : 1;	/* free worker scheduled fast */
	u8			freeing : 1;	/* lgr is being freed */

	bool			is_smcd;	/* SMC-R or SMC-D */
	union {
		struct { /* SMC-R */
			enum smc_lgr_role	role;
						/* client or server */
			struct smc_link		lnk[SMC_LINKS_PER_LGR_MAX];
						/* smc link */
			char			peer_systemid[SMC_SYSTEMID_LEN];
						/* unique system_id of peer */
			struct smc_rtoken	rtokens[SMC_RMBS_PER_LGR_MAX]
						[SMC_LINKS_PER_LGR_MAX];
						/* remote addr/key pairs */
			DECLARE_BITMAP(rtokens_used_mask, SMC_RMBS_PER_LGR_MAX);
						/* used rtoken elements */
			u8			next_link_id;
			struct list_head	llc_event_q;
						/* queue for llc events */
			spinlock_t		llc_event_q_lock;
						/* protects llc_event_q */
			struct work_struct	llc_event_work;
						/* llc event worker */
		};
		struct { /* SMC-D */
			u64			peer_gid;
						/* Peer GID (remote) */
			struct smcd_dev		*smcd;
						/* ISM device for VLAN reg. */
			u8			peer_shutdown : 1;
						/* peer triggered shutdownn */
		};
	};
};

struct smc_clc_msg_local;

struct smc_init_info {
	u8			is_smcd;
	unsigned short		vlan_id;
	int			srv_first_contact;
	int			cln_first_contact;
	/* SMC-R */
	struct smc_clc_msg_local *ib_lcl;
	struct smc_ib_device	*ib_dev;
	u8			ib_gid[SMC_GID_SIZE];
	u8			ib_port;
	u32			ib_clcqpn;
	/* SMC-D */
	u64			ism_gid;
	struct smcd_dev		*ism_dev;
};

/* Find the connection associated with the given alert token in the link group.
 * To use rbtrees we have to implement our own search core.
 * Requires @conns_lock
 * @token	alert token to search for
 * @lgr		 link group to search in
 * Returns connection associated with token if found, NULL otherwise.
 */
static inline struct smc_connection *smc_lgr_find_conn(
	u32 token, struct smc_link_group *lgr)
{
	struct smc_connection *res = NULL;
	struct rb_node *node;

	node = lgr->conns_all.rb_node;
	while (node) {
		struct smc_connection *cur = rb_entry(node,
					struct smc_connection, alert_node);

		if (cur->alert_token_local > token) {
			node = node->rb_left;
		} else {
			if (cur->alert_token_local < token) {
				node = node->rb_right;
			} else {
				res = cur;
				break;
			}
		}
	}

	return res;
}

/* returns true if the specified link is usable */
static inline bool smc_link_usable(struct smc_link *lnk)
{
	if (lnk->state == SMC_LNK_UNUSED || lnk->state == SMC_LNK_INACTIVE)
		return false;
	return true;
}

struct smc_sock;
struct smc_clc_msg_accept_confirm;
struct smc_clc_msg_local;

void smc_lgr_forget(struct smc_link_group *lgr);
void smc_lgr_cleanup_early(struct smc_connection *conn);
void smc_lgr_terminate_sched(struct smc_link_group *lgr);
void smc_port_terminate(struct smc_ib_device *smcibdev, u8 ibport);
void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid,
			unsigned short vlan);
void smc_smcd_terminate_all(struct smcd_dev *dev);
void smc_smcr_terminate_all(struct smc_ib_device *smcibdev);
int smc_buf_create(struct smc_sock *smc, bool is_smcd);
int smc_uncompress_bufsize(u8 compressed);
int smc_rmb_rtoken_handling(struct smc_connection *conn, struct smc_link *link,
			    struct smc_clc_msg_accept_confirm *clc);
int smc_rtoken_add(struct smc_link *lnk, __be64 nw_vaddr, __be32 nw_rkey);
int smc_rtoken_delete(struct smc_link *lnk, __be32 nw_rkey);
void smc_sndbuf_sync_sg_for_cpu(struct smc_connection *conn);
void smc_sndbuf_sync_sg_for_device(struct smc_connection *conn);
void smc_rmb_sync_sg_for_cpu(struct smc_connection *conn);
void smc_rmb_sync_sg_for_device(struct smc_connection *conn);
int smc_vlan_by_tcpsk(struct socket *clcsock, struct smc_init_info *ini);

void smc_conn_free(struct smc_connection *conn);
int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini);
void smc_lgr_schedule_free_work_fast(struct smc_link_group *lgr);
int smc_core_init(void);
void smc_core_exit(void);

static inline struct smc_link_group *smc_get_lgr(struct smc_link *link)
{
	return link->lgr;
}
#endif