/*
 * Copyright (c) 2003-2007 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.
 */

#ifndef _LINUX_SUNRPC_XPRT_RDMA_H
#define _LINUX_SUNRPC_XPRT_RDMA_H

#include <linux/wait.h>                 /* wait_queue_head_t, etc */
#include <linux/spinlock.h>             /* spinlock_t, etc */
#include <linux/atomic.h>                       /* atomic_t, etc */
#include <linux/workqueue.h>            /* struct work_struct */

#include <rdma/rdma_cm.h>               /* RDMA connection api */
#include <rdma/ib_verbs.h>              /* RDMA verbs api */

#include <linux/sunrpc/clnt.h>          /* rpc_xprt */
#include <linux/sunrpc/rpc_rdma.h>      /* RPC/RDMA protocol */
#include <linux/sunrpc/xprtrdma.h>      /* xprt parameters */

#define RDMA_RESOLVE_TIMEOUT    (5000)  /* 5 seconds */
#define RDMA_CONNECT_RETRY_MAX  (2)     /* retries if no listener backlog */

#define RPCRDMA_BIND_TO         (60U * HZ)
#define RPCRDMA_INIT_REEST_TO   (5U * HZ)
#define RPCRDMA_MAX_REEST_TO    (30U * HZ)
#define RPCRDMA_IDLE_DISC_TO    (5U * 60 * HZ)

/*
 * Interface Adapter -- one per transport instance
 */
struct rpcrdma_ia {
        const struct rpcrdma_memreg_ops *ri_ops;
        rwlock_t                ri_qplock;
        struct ib_device        *ri_device;
        struct rdma_cm_id       *ri_id;
        struct ib_pd            *ri_pd;
        struct ib_mr            *ri_dma_mr;
        struct completion       ri_done;
        int                     ri_async_rc;
        unsigned int            ri_max_frmr_depth;
        struct ib_qp_attr       ri_qp_attr;
        struct ib_qp_init_attr  ri_qp_init_attr;
};

/*
 * RDMA Endpoint -- one per transport instance
 */

struct rpcrdma_ep {
        atomic_t                rep_cqcount;
        int                     rep_cqinit;
        int                     rep_connected;
        struct ib_qp_init_attr  rep_attr;
        wait_queue_head_t       rep_connect_wait;
        struct rdma_conn_param  rep_remote_cma;
        struct sockaddr_storage rep_remote_addr;
        struct delayed_work     rep_connect_worker;
};

#define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
#define DECR_CQCOUNT(ep) atomic_sub_return(1, &(ep)->rep_cqcount)

/* Pre-allocate extra Work Requests for handling backward receives
 * and sends. This is a fixed value because the Work Queues are
 * allocated when the forward channel is set up.
 */
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
#define RPCRDMA_BACKWARD_WRS            (8)
#else
#define RPCRDMA_BACKWARD_WRS            (0)
#endif

/* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
 *
 * The below structure appears at the front of a large region of kmalloc'd
 * memory, which always starts on a good alignment boundary.
 */

struct rpcrdma_regbuf {
        size_t                  rg_size;
        struct rpcrdma_req      *rg_owner;
        struct ib_sge           rg_iov;
        __be32                  rg_base[0] __attribute__ ((aligned(256)));
};

static inline u64
rdmab_addr(struct rpcrdma_regbuf *rb)
{
        return rb->rg_iov.addr;
}

static inline u32
rdmab_length(struct rpcrdma_regbuf *rb)
{
        return rb->rg_iov.length;
}

static inline u32
rdmab_lkey(struct rpcrdma_regbuf *rb)
{
        return rb->rg_iov.lkey;
}

static inline struct rpcrdma_msg *
rdmab_to_msg(struct rpcrdma_regbuf *rb)
{
        return (struct rpcrdma_msg *)rb->rg_base;
}

#define RPCRDMA_DEF_GFP         (GFP_NOIO | __GFP_NOWARN)

/*
 * struct rpcrdma_rep -- this structure encapsulates state required to recv
 * and complete a reply, asychronously. It needs several pieces of
 * state:
 *   o recv buffer (posted to provider)
 *   o ib_sge (also donated to provider)
 *   o status of reply (length, success or not)
 *   o bookkeeping state to get run by tasklet (list, etc)
 *
 * These are allocated during initialization, per-transport instance;
 * however, the tasklet execution list itself is global, as it should
 * always be pretty short.
 *
 * N of these are associated with a transport instance, and stored in
 * struct rpcrdma_buffer. N is the max number of outstanding requests.
 */

#define RPCRDMA_MAX_DATA_SEGS   ((1 * 1024 * 1024) / PAGE_SIZE)
#define RPCRDMA_MAX_SEGS        (RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */

struct rpcrdma_buffer;

struct rpcrdma_rep {
        struct ib_cqe           rr_cqe;
        unsigned int            rr_len;
        struct ib_device        *rr_device;
        struct rpcrdma_xprt     *rr_rxprt;
        struct work_struct      rr_work;
        struct list_head        rr_list;
        struct rpcrdma_regbuf   *rr_rdmabuf;
};

#define RPCRDMA_BAD_LEN         (~0U)

/*
 * struct rpcrdma_mw - external memory region metadata
 *
 * An external memory region is any buffer or page that is registered
 * on the fly (ie, not pre-registered).
 *
 * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
 * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
 * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
 * track of registration metadata while each RPC is pending.
 * rpcrdma_deregister_external() uses this metadata to unmap and
 * release these resources when an RPC is complete.
 */
enum rpcrdma_frmr_state {
        FRMR_IS_INVALID,        /* ready to be used */
        FRMR_IS_VALID,          /* in use */
        FRMR_IS_STALE,          /* failed completion */
};

struct rpcrdma_frmr {
        struct scatterlist              *sg;
        int                             sg_nents;
        struct ib_mr                    *fr_mr;
        struct ib_cqe                   fr_cqe;
        enum rpcrdma_frmr_state         fr_state;
        struct completion               fr_linv_done;
        struct work_struct              fr_work;
        struct rpcrdma_xprt             *fr_xprt;
        union {
                struct ib_reg_wr        fr_regwr;
                struct ib_send_wr       fr_invwr;
        };
};

struct rpcrdma_fmr {
        struct ib_fmr           *fmr;
        u64                     *physaddrs;
};

struct rpcrdma_mw {
        union {
                struct rpcrdma_fmr      fmr;
                struct rpcrdma_frmr     frmr;
        };
        struct list_head        mw_list;
        struct list_head        mw_all;
};

/*
 * struct rpcrdma_req -- structure central to the request/reply sequence.
 *
 * N of these are associated with a transport instance, and stored in
 * struct rpcrdma_buffer. N is the max number of outstanding requests.
 *
 * It includes pre-registered buffer memory for send AND recv.
 * The recv buffer, however, is not owned by this structure, and
 * is "donated" to the hardware when a recv is posted. When a
 * reply is handled, the recv buffer used is given back to the
 * struct rpcrdma_req associated with the request.
 *
 * In addition to the basic memory, this structure includes an array
 * of iovs for send operations. The reason is that the iovs passed to
 * ib_post_{send,recv} must not be modified until the work request
 * completes.
 *
 * NOTES:
 *   o RPCRDMA_MAX_SEGS is the max number of addressible chunk elements we
 *     marshal. The number needed varies depending on the iov lists that
 *     are passed to us, the memory registration mode we are in, and if
 *     physical addressing is used, the layout.
 */

struct rpcrdma_mr_seg {         /* chunk descriptors */
        struct rpcrdma_mw *rl_mw;       /* registered MR */
        u64             mr_base;        /* registration result */
        u32             mr_rkey;        /* registration result */
        u32             mr_len;         /* length of chunk or segment */
        int             mr_nsegs;       /* number of segments in chunk or 0 */
        enum dma_data_direction mr_dir; /* segment mapping direction */
        dma_addr_t      mr_dma;         /* segment mapping address */
        size_t          mr_dmalen;      /* segment mapping length */
        struct page     *mr_page;       /* owning page, if any */
        char            *mr_offset;     /* kva if no page, else offset */
};

#define RPCRDMA_MAX_IOVS        (2)

struct rpcrdma_req {
        struct list_head        rl_free;
        unsigned int            rl_niovs;
        unsigned int            rl_nchunks;
        unsigned int            rl_connect_cookie;
        struct rpcrdma_buffer   *rl_buffer;
        struct rpcrdma_rep      *rl_reply;/* holder for reply buffer */
        struct ib_sge           rl_send_iov[RPCRDMA_MAX_IOVS];
        struct rpcrdma_regbuf   *rl_rdmabuf;
        struct rpcrdma_regbuf   *rl_sendbuf;
        struct rpcrdma_mr_seg   rl_segments[RPCRDMA_MAX_SEGS];

        struct ib_cqe           rl_cqe;
        struct list_head        rl_all;
        bool                    rl_backchannel;
};

static inline struct rpcrdma_req *
rpcr_to_rdmar(struct rpc_rqst *rqst)
{
        void *buffer = rqst->rq_buffer;
        struct rpcrdma_regbuf *rb;

        rb = container_of(buffer, struct rpcrdma_regbuf, rg_base);
        return rb->rg_owner;
}

/*
 * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
 * inline requests/replies, and client/server credits.
 *
 * One of these is associated with a transport instance
 */
struct rpcrdma_buffer {
        spinlock_t              rb_mwlock;      /* protect rb_mws list */
        struct list_head        rb_mws;
        struct list_head        rb_all;
        char                    *rb_pool;

        spinlock_t              rb_lock;        /* protect buf lists */
        struct list_head        rb_send_bufs;
        struct list_head        rb_recv_bufs;
        u32                     rb_max_requests;
        atomic_t                rb_credits;     /* most recent credit grant */

        u32                     rb_bc_srv_max_requests;
        spinlock_t              rb_reqslock;    /* protect rb_allreqs */
        struct list_head        rb_allreqs;

        u32                     rb_bc_max_requests;
};
#define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)

/*
 * Internal structure for transport instance creation. This
 * exists primarily for modularity.
 *
 * This data should be set with mount options
 */
struct rpcrdma_create_data_internal {
        struct sockaddr_storage addr;   /* RDMA server address */
        unsigned int    max_requests;   /* max requests (slots) in flight */
        unsigned int    rsize;          /* mount rsize - max read hdr+data */
        unsigned int    wsize;          /* mount wsize - max write hdr+data */
        unsigned int    inline_rsize;   /* max non-rdma read data payload */
        unsigned int    inline_wsize;   /* max non-rdma write data payload */
        unsigned int    padding;        /* non-rdma write header padding */
};

#define RPCRDMA_INLINE_READ_THRESHOLD(rq) \
        (rpcx_to_rdmad(rq->rq_xprt).inline_rsize)

#define RPCRDMA_INLINE_WRITE_THRESHOLD(rq)\
        (rpcx_to_rdmad(rq->rq_xprt).inline_wsize)

#define RPCRDMA_INLINE_PAD_VALUE(rq)\
        rpcx_to_rdmad(rq->rq_xprt).padding

/*
 * Statistics for RPCRDMA
 */
struct rpcrdma_stats {
        unsigned long           read_chunk_count;
        unsigned long           write_chunk_count;
        unsigned long           reply_chunk_count;

        unsigned long long      total_rdma_request;
        unsigned long long      total_rdma_reply;

        unsigned long long      pullup_copy_count;
        unsigned long long      fixup_copy_count;
        unsigned long           hardway_register_count;
        unsigned long           failed_marshal_count;
        unsigned long           bad_reply_count;
        unsigned long           nomsg_call_count;
        unsigned long           bcall_count;
};

/*
 * Per-registration mode operations
 */
struct rpcrdma_xprt;
struct rpcrdma_memreg_ops {
        int             (*ro_map)(struct rpcrdma_xprt *,
                                  struct rpcrdma_mr_seg *, int, bool);
        void            (*ro_unmap_sync)(struct rpcrdma_xprt *,
                                         struct rpcrdma_req *);
        int             (*ro_unmap)(struct rpcrdma_xprt *,
                                    struct rpcrdma_mr_seg *);
        int             (*ro_open)(struct rpcrdma_ia *,
                                   struct rpcrdma_ep *,
                                   struct rpcrdma_create_data_internal *);
        size_t          (*ro_maxpages)(struct rpcrdma_xprt *);
        int             (*ro_init)(struct rpcrdma_xprt *);
        void            (*ro_destroy)(struct rpcrdma_buffer *);
        const char      *ro_displayname;
};

extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
extern const struct rpcrdma_memreg_ops rpcrdma_physical_memreg_ops;

/*
 * RPCRDMA transport -- encapsulates the structures above for
 * integration with RPC.
 *
 * The contained structures are embedded, not pointers,
 * for convenience. This structure need not be visible externally.
 *
 * It is allocated and initialized during mount, and released
 * during unmount.
 */
struct rpcrdma_xprt {
        struct rpc_xprt         rx_xprt;
        struct rpcrdma_ia       rx_ia;
        struct rpcrdma_ep       rx_ep;
        struct rpcrdma_buffer   rx_buf;
        struct rpcrdma_create_data_internal rx_data;
        struct delayed_work     rx_connect_worker;
        struct rpcrdma_stats    rx_stats;
};

#define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
#define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)

/* Setting this to 0 ensures interoperability with early servers.
 * Setting this to 1 enhances certain unaligned read/write performance.
 * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
extern int xprt_rdma_pad_optimize;

/*
 * Interface Adapter calls - xprtrdma/verbs.c
 */
int rpcrdma_ia_open(struct rpcrdma_xprt *, struct sockaddr *, int);
void rpcrdma_ia_close(struct rpcrdma_ia *);

/*
 * Endpoint calls - xprtrdma/verbs.c
 */
int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
                                struct rpcrdma_create_data_internal *);
void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);

int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
                                struct rpcrdma_req *);
int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
                                struct rpcrdma_rep *);

/*
 * Buffer calls - xprtrdma/verbs.c
 */
struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
void rpcrdma_destroy_req(struct rpcrdma_ia *, struct rpcrdma_req *);
int rpcrdma_buffer_create(struct rpcrdma_xprt *);
void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);

struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
void rpcrdma_buffer_put(struct rpcrdma_req *);
void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);

struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(struct rpcrdma_ia *,
                                            size_t, gfp_t);
void rpcrdma_free_regbuf(struct rpcrdma_ia *,
                         struct rpcrdma_regbuf *);

unsigned int rpcrdma_max_segments(struct rpcrdma_xprt *);
int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);

int frwr_alloc_recovery_wq(void);
void frwr_destroy_recovery_wq(void);

int rpcrdma_alloc_wq(void);
void rpcrdma_destroy_wq(void);

/*
 * Wrappers for chunk registration, shared by read/write chunk code.
 */

void rpcrdma_mapping_error(struct rpcrdma_mr_seg *);

static inline enum dma_data_direction
rpcrdma_data_dir(bool writing)
{
        return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
}

static inline void
rpcrdma_map_one(struct ib_device *device, struct rpcrdma_mr_seg *seg,
                enum dma_data_direction direction)
{
        seg->mr_dir = direction;
        seg->mr_dmalen = seg->mr_len;

        if (seg->mr_page)
                seg->mr_dma = ib_dma_map_page(device,
                                seg->mr_page, offset_in_page(seg->mr_offset),
                                seg->mr_dmalen, seg->mr_dir);
        else
                seg->mr_dma = ib_dma_map_single(device,
                                seg->mr_offset,
                                seg->mr_dmalen, seg->mr_dir);

        if (ib_dma_mapping_error(device, seg->mr_dma))
                rpcrdma_mapping_error(seg);
}

static inline void
rpcrdma_unmap_one(struct ib_device *device, struct rpcrdma_mr_seg *seg)
{
        if (seg->mr_page)
                ib_dma_unmap_page(device,
                                  seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
        else
                ib_dma_unmap_single(device,
                                    seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
}

/*
 * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
 */
void rpcrdma_connect_worker(struct work_struct *);
void rpcrdma_conn_func(struct rpcrdma_ep *);
void rpcrdma_reply_handler(struct rpcrdma_rep *);

/*
 * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
 */
int rpcrdma_marshal_req(struct rpc_rqst *);

/* RPC/RDMA module init - xprtrdma/transport.c
 */
extern unsigned int xprt_rdma_max_inline_read;
void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
int xprt_rdma_init(void);
void xprt_rdma_cleanup(void);

/* Backchannel calls - xprtrdma/backchannel.c
 */
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
int xprt_rdma_bc_up(struct svc_serv *, struct net *);
int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
#endif  /* CONFIG_SUNRPC_BACKCHANNEL */

extern struct xprt_class xprt_rdma_bc;

#endif                          /* _LINUX_SUNRPC_XPRT_RDMA_H */