/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
/*
 * Copyright (c) 2005-2006 Network Appliance, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the BSD-type
 * license below:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *      Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *      Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials provided
 *      with the distribution.
 *
 *      Neither the name of the Network Appliance, Inc. nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Author: Tom Tucker <tom@opengridcomputing.com>
 */

#ifndef SVC_RDMA_H
#define SVC_RDMA_H
#include <linux/llist.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/sunrpc/rpc_rdma_cid.h>
#include <linux/sunrpc/svc_rdma_pcl.h>
#include <linux/sunrpc/rdma_rn.h>

#include <linux/percpu_counter.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>

/* Default and maximum inline threshold sizes */
enum {
        RPCRDMA_PULLUP_THRESH = RPCRDMA_V1_DEF_INLINE_SIZE >> 1,
        RPCRDMA_DEF_INLINE_THRESH = 4096,
        RPCRDMA_MAX_INLINE_THRESH = 65536
};

/* RPC/RDMA parameters and stats */
extern unsigned int svcrdma_ord;
extern unsigned int svcrdma_max_requests;
extern unsigned int svcrdma_max_bc_requests;
extern unsigned int svcrdma_max_req_size;
extern struct workqueue_struct *svcrdma_wq;

extern struct percpu_counter svcrdma_stat_read;
extern struct percpu_counter svcrdma_stat_recv;
extern struct percpu_counter svcrdma_stat_sq_starve;
extern struct percpu_counter svcrdma_stat_write;

struct svcxprt_rdma {
        struct svc_xprt      sc_xprt;           /* SVC transport structure */
        struct rdma_cm_id    *sc_cm_id;         /* RDMA connection id */
        struct list_head     sc_accept_q;       /* Conn. waiting accept */
        struct rpcrdma_notification sc_rn;      /* removal notification */
        int                  sc_ord;            /* RDMA read limit */
        int                  sc_max_send_sges;
        bool                 sc_snd_w_inv;      /* OK to use Send With Invalidate */

        atomic_t             sc_sq_avail;       /* SQEs ready to be consumed */
        unsigned int         sc_sq_depth;       /* Depth of SQ */
        __be32               sc_fc_credits;     /* Forward credits */
        u32                  sc_max_requests;   /* Max requests */
        u32                  sc_max_bc_requests;/* Backward credits */
        int                  sc_max_req_size;   /* Size of each RQ WR buf */
        u8                   sc_port_num;

        struct ib_pd         *sc_pd;

        spinlock_t           sc_send_lock;
        struct llist_head    sc_send_ctxts;
        spinlock_t           sc_rw_ctxt_lock;
        struct llist_head    sc_rw_ctxts;

        u32                  sc_pending_recvs;
        u32                  sc_recv_batch;
        struct list_head     sc_rq_dto_q;
        struct list_head     sc_read_complete_q;
        spinlock_t           sc_rq_dto_lock;
        struct ib_qp         *sc_qp;
        struct ib_cq         *sc_rq_cq;
        struct ib_cq         *sc_sq_cq;

        spinlock_t           sc_lock;           /* transport lock */

        wait_queue_head_t    sc_send_wait;      /* SQ exhaustion waitlist */
        unsigned long        sc_flags;
        struct work_struct   sc_work;

        struct llist_head    sc_recv_ctxts;

        atomic_t             sc_completion_ids;
};
/* sc_flags */
#define RDMAXPRT_CONN_PENDING   3

static inline struct svcxprt_rdma *svc_rdma_rqst_rdma(struct svc_rqst *rqstp)
{
        struct svc_xprt *xprt = rqstp->rq_xprt;

        return container_of(xprt, struct svcxprt_rdma, sc_xprt);
}

/*
 * Default connection parameters
 */
enum {
        RPCRDMA_LISTEN_BACKLOG  = 10,
        RPCRDMA_MAX_REQUESTS    = 128,
        RPCRDMA_MAX_BC_REQUESTS = 2,
};

#define RPCSVC_MAXPAYLOAD_RDMA  RPCSVC_MAXPAYLOAD

/**
 * svc_rdma_send_cid_init - Initialize a Receive Queue completion ID
 * @rdma: controlling transport
 * @cid: completion ID to initialize
 */
static inline void svc_rdma_recv_cid_init(struct svcxprt_rdma *rdma,
                                          struct rpc_rdma_cid *cid)
{
        cid->ci_queue_id = rdma->sc_rq_cq->res.id;
        cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids);
}

/**
 * svc_rdma_send_cid_init - Initialize a Send Queue completion ID
 * @rdma: controlling transport
 * @cid: completion ID to initialize
 */
static inline void svc_rdma_send_cid_init(struct svcxprt_rdma *rdma,
                                          struct rpc_rdma_cid *cid)
{
        cid->ci_queue_id = rdma->sc_sq_cq->res.id;
        cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids);
}

/*
 * A chunk context tracks all I/O for moving one Read or Write
 * chunk. This is a set of rdma_rw's that handle data movement
 * for all segments of one chunk.
 */
struct svc_rdma_chunk_ctxt {
        struct rpc_rdma_cid     cc_cid;
        struct ib_cqe           cc_cqe;
        struct list_head        cc_rwctxts;
        ktime_t                 cc_posttime;
        int                     cc_sqecount;
};

struct svc_rdma_recv_ctxt {
        struct llist_node       rc_node;
        struct list_head        rc_list;
        struct ib_recv_wr       rc_recv_wr;
        struct ib_cqe           rc_cqe;
        struct rpc_rdma_cid     rc_cid;
        struct ib_sge           rc_recv_sge;
        void                    *rc_recv_buf;
        struct xdr_stream       rc_stream;
        u32                     rc_byte_len;
        u32                     rc_inv_rkey;
        __be32                  rc_msgtype;

        /* State for pulling a Read chunk */
        unsigned int            rc_pageoff;
        unsigned int            rc_curpage;
        unsigned int            rc_readbytes;
        struct xdr_buf          rc_saved_arg;
        struct svc_rdma_chunk_ctxt      rc_cc;

        struct svc_rdma_pcl     rc_call_pcl;

        struct svc_rdma_pcl     rc_read_pcl;
        struct svc_rdma_chunk   *rc_cur_result_payload;
        struct svc_rdma_pcl     rc_write_pcl;
        struct svc_rdma_pcl     rc_reply_pcl;

        unsigned int            rc_page_count;
        unsigned long           rc_maxpages;
        struct page             *rc_pages[] __counted_by(rc_maxpages);
};

/*
 * State for sending a Write chunk.
 *  - Tracks progress of writing one chunk over all its segments
 *  - Stores arguments for the SGL constructor functions
 */
struct svc_rdma_write_info {
        struct svcxprt_rdma     *wi_rdma;

        const struct svc_rdma_chunk     *wi_chunk;

        /* write state of this chunk */
        unsigned int            wi_seg_off;
        unsigned int            wi_seg_no;

        /* SGL constructor arguments */
        const struct xdr_buf    *wi_xdr;
        unsigned char           *wi_base;
        unsigned int            wi_next_off;

        struct svc_rdma_chunk_ctxt      wi_cc;
        struct work_struct      wi_work;
};

struct svc_rdma_send_ctxt {
        struct llist_node       sc_node;
        struct rpc_rdma_cid     sc_cid;
        struct work_struct      sc_work;

        struct svcxprt_rdma     *sc_rdma;
        struct ib_send_wr       sc_send_wr;
        struct ib_send_wr       *sc_wr_chain;
        int                     sc_sqecount;
        struct ib_cqe           sc_cqe;
        struct xdr_buf          sc_hdrbuf;
        struct xdr_stream       sc_stream;
        struct svc_rdma_write_info sc_reply_info;
        void                    *sc_xprt_buf;
        int                     sc_page_count;
        int                     sc_cur_sge_no;
        unsigned long           sc_maxpages;
        struct page             **sc_pages;
        struct ib_sge           sc_sges[];
};

/* svc_rdma_backchannel.c */
extern void svc_rdma_handle_bc_reply(struct svc_rqst *rqstp,
                                     struct svc_rdma_recv_ctxt *rctxt);

/* svc_rdma_recvfrom.c */
extern void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma);
extern bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma);
extern struct svc_rdma_recv_ctxt *
                svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma);
extern void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
                                   struct svc_rdma_recv_ctxt *ctxt);
extern void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma);
extern void svc_rdma_release_ctxt(struct svc_xprt *xprt, void *ctxt);
extern int svc_rdma_recvfrom(struct svc_rqst *);

/* svc_rdma_rw.c */
extern void svc_rdma_cc_init(struct svcxprt_rdma *rdma,
                             struct svc_rdma_chunk_ctxt *cc);
extern void svc_rdma_destroy_rw_ctxts(struct svcxprt_rdma *rdma);
extern void svc_rdma_cc_init(struct svcxprt_rdma *rdma,
                             struct svc_rdma_chunk_ctxt *cc);
extern void svc_rdma_cc_release(struct svcxprt_rdma *rdma,
                                struct svc_rdma_chunk_ctxt *cc,
                                enum dma_data_direction dir);
extern void svc_rdma_reply_chunk_release(struct svcxprt_rdma *rdma,
                                         struct svc_rdma_send_ctxt *ctxt);
extern int svc_rdma_send_write_list(struct svcxprt_rdma *rdma,
                                    const struct svc_rdma_recv_ctxt *rctxt,
                                    const struct xdr_buf *xdr);
extern int svc_rdma_prepare_reply_chunk(struct svcxprt_rdma *rdma,
                                        const struct svc_rdma_pcl *write_pcl,
                                        const struct svc_rdma_pcl *reply_pcl,
                                        struct svc_rdma_send_ctxt *sctxt,
                                        const struct xdr_buf *xdr);
extern int svc_rdma_process_read_list(struct svcxprt_rdma *rdma,
                                      struct svc_rqst *rqstp,
                                      struct svc_rdma_recv_ctxt *head);

/* svc_rdma_sendto.c */
extern void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma);
extern struct svc_rdma_send_ctxt *
                svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma);
extern void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
                                   struct svc_rdma_send_ctxt *ctxt);
extern int svc_rdma_post_send(struct svcxprt_rdma *rdma,
                              struct svc_rdma_send_ctxt *ctxt);
extern int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
                                  struct svc_rdma_send_ctxt *sctxt,
                                  const struct svc_rdma_pcl *write_pcl,
                                  const struct svc_rdma_pcl *reply_pcl,
                                  const struct xdr_buf *xdr);
extern void svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
                                    struct svc_rdma_send_ctxt *sctxt,
                                    struct svc_rdma_recv_ctxt *rctxt,
                                    int status);
extern void svc_rdma_wake_send_waiters(struct svcxprt_rdma *rdma, int avail);
extern int svc_rdma_sendto(struct svc_rqst *);
extern int svc_rdma_result_payload(struct svc_rqst *rqstp, unsigned int offset,
                                   unsigned int length);

/* svc_rdma_transport.c */
extern struct svc_xprt_class svc_rdma_class;
#ifdef CONFIG_SUNRPC_BACKCHANNEL
extern struct svc_xprt_class svc_rdma_bc_class;
#endif

/* svc_rdma.c */
extern int svc_rdma_init(void);
extern void svc_rdma_cleanup(void);

#endif