svc_rdma.h

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/*
 * 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 <[email protected]>
 */

#ifndef SVC_RDMA_H
#define SVC_RDMA_H
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#define SVCRDMA_DEBUG

/* RPC/RDMA parameters and stats */
extern unsigned int svcrdma_ord;
extern unsigned int svcrdma_max_requests;
extern unsigned int svcrdma_max_req_size;

extern atomic_t rdma_stat_recv;
extern atomic_t rdma_stat_read;
extern atomic_t rdma_stat_write;
extern atomic_t rdma_stat_sq_starve;
extern atomic_t rdma_stat_rq_starve;
extern atomic_t rdma_stat_rq_poll;
extern atomic_t rdma_stat_rq_prod;
extern atomic_t rdma_stat_sq_poll;
extern atomic_t rdma_stat_sq_prod;

#define RPCRDMA_VERSION 1

/*
 * Contexts are built when an RDMA request is created and are a
 * record of the resources that can be recovered when the request
 * completes.
 */
struct svc_rdma_op_ctxt {
    struct svc_rdma_op_ctxt *read_hdr;
    struct svc_rdma_fastreg_mr *frmr;
    int hdr_count;
    struct xdr_buf arg;
    struct list_head dto_q;
    enum ib_wr_opcode wr_op;
    enum ib_wc_status wc_status;
    u32 byte_len;
    struct svcxprt_rdma *xprt;
    unsigned long flags;
    enum dma_data_direction direction;
    int count;
    struct ib_sge sge[RPCSVC_MAXPAGES];
    struct page *pages[RPCSVC_MAXPAGES];
};

/*
 * NFS_ requests are mapped on the client side by the chunk lists in
 * the RPCRDMA header. During the fetching of the RPC from the client
 * and the writing of the reply to the client, the memory in the
 * client and the memory in the server must be mapped as contiguous
 * vaddr/len for access by the hardware. These data strucures keep
 * these mappings.
 *
 * For an RDMA_WRITE, the 'sge' maps the RPC REPLY. For RDMA_READ, the
 * 'sge' in the svc_rdma_req_map maps the server side RPC reply and the
 * 'ch' field maps the read-list of the RPCRDMA header to the 'sge'
 * mapping of the reply.
 */
struct svc_rdma_chunk_sge {
    int start;      /* sge no for this chunk */
    int count;      /* sge count for this chunk */
};
struct svc_rdma_fastreg_mr {
    struct ib_mr *mr;
    void *kva;
    struct ib_fast_reg_page_list *page_list;
    int page_list_len;
    unsigned long access_flags;
    unsigned long map_len;
    enum dma_data_direction direction;
    struct list_head frmr_list;
};
struct svc_rdma_req_map {
    struct svc_rdma_fastreg_mr *frmr;
    unsigned long count;
    union {
        struct kvec sge[RPCSVC_MAXPAGES];
        struct svc_rdma_chunk_sge ch[RPCSVC_MAXPAGES];
    };
};
#define RDMACTXT_F_FAST_UNREG   1
#define RDMACTXT_F_LAST_CTXT    2

#define SVCRDMA_DEVCAP_FAST_REG     1   /* fast mr registration */
#define SVCRDMA_DEVCAP_READ_W_INV   2   /* read w/ invalidate */

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 */
    int          sc_ord;        /* RDMA read limit */
    int                  sc_max_sge;

    int                  sc_sq_depth;   /* Depth of SQ */
    atomic_t             sc_sq_count;   /* Number of SQ WR on queue */

    int                  sc_max_requests;   /* Depth of RQ */
    int                  sc_max_req_size;   /* Size of each RQ WR buf */

    struct ib_pd         *sc_pd;

    atomic_t         sc_dma_used;
    atomic_t         sc_ctxt_used;
    struct list_head     sc_rq_dto_q;
    spinlock_t       sc_rq_dto_lock;
    struct ib_qp         *sc_qp;
    struct ib_cq         *sc_rq_cq;
    struct ib_cq         *sc_sq_cq;
    struct ib_mr         *sc_phys_mr;   /* MR for server memory */
    u32          sc_dev_caps;   /* distilled device caps */
    u32          sc_dma_lkey;   /* local dma key */
    unsigned int         sc_frmr_pg_list_len;
    struct list_head     sc_frmr_q;
    spinlock_t       sc_frmr_q_lock;

    spinlock_t       sc_lock;       /* transport lock */

    wait_queue_head_t    sc_send_wait;  /* SQ exhaustion waitlist */
    unsigned long        sc_flags;
    struct list_head     sc_dto_q;      /* DTO tasklet I/O pending Q */
    struct list_head     sc_read_complete_q;
    struct work_struct   sc_work;
};
/* sc_flags */
#define RDMAXPRT_RQ_PENDING 1
#define RDMAXPRT_SQ_PENDING 2
#define RDMAXPRT_CONN_PENDING   3

#define RPCRDMA_LISTEN_BACKLOG  10
/* The default ORD value is based on two outstanding full-size writes with a
 * page size of 4k, or 32k * 2 ops / 4k = 16 outstanding RDMA_READ.  */
#define RPCRDMA_ORD             (64/4)
#define RPCRDMA_SQ_DEPTH_MULT   8
#define RPCRDMA_MAX_THREADS     16
#define RPCRDMA_MAX_REQUESTS    16
#define RPCRDMA_MAX_REQ_SIZE    4096

/* svc_rdma_marshal.c */
extern void svc_rdma_rcl_chunk_counts(struct rpcrdma_read_chunk *,
                      int *, int *);
extern int svc_rdma_xdr_decode_req(struct rpcrdma_msg **, struct svc_rqst *);
extern int svc_rdma_xdr_decode_deferred_req(struct svc_rqst *);
extern int svc_rdma_xdr_encode_error(struct svcxprt_rdma *,
                     struct rpcrdma_msg *,
                     enum rpcrdma_errcode, u32 *);
extern void svc_rdma_xdr_encode_write_list(struct rpcrdma_msg *, int);
extern void svc_rdma_xdr_encode_reply_array(struct rpcrdma_write_array *, int);
extern void svc_rdma_xdr_encode_array_chunk(struct rpcrdma_write_array *, int,
                        __be32, __be64, u32);
extern void svc_rdma_xdr_encode_reply_header(struct svcxprt_rdma *,
                         struct rpcrdma_msg *,
                         struct rpcrdma_msg *,
                         enum rpcrdma_proc);
extern int svc_rdma_xdr_get_reply_hdr_len(struct rpcrdma_msg *);

/* svc_rdma_recvfrom.c */
extern int svc_rdma_recvfrom(struct svc_rqst *);

/* svc_rdma_sendto.c */
extern int svc_rdma_sendto(struct svc_rqst *);

/* svc_rdma_transport.c */
extern int svc_rdma_send(struct svcxprt_rdma *, struct ib_send_wr *);
extern void svc_rdma_send_error(struct svcxprt_rdma *, struct rpcrdma_msg *,
                enum rpcrdma_errcode);
struct page *svc_rdma_get_page(void);
extern int svc_rdma_post_recv(struct svcxprt_rdma *);
extern int svc_rdma_create_listen(struct svc_serv *, int, struct sockaddr *);
extern struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *);
extern void svc_rdma_put_context(struct svc_rdma_op_ctxt *, int);
extern void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt);
extern struct svc_rdma_req_map *svc_rdma_get_req_map(void);
extern void svc_rdma_put_req_map(struct svc_rdma_req_map *);
extern int svc_rdma_fastreg(struct svcxprt_rdma *, struct svc_rdma_fastreg_mr *);
extern struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *);
extern void svc_rdma_put_frmr(struct svcxprt_rdma *,
                  struct svc_rdma_fastreg_mr *);
extern void svc_sq_reap(struct svcxprt_rdma *);
extern void svc_rq_reap(struct svcxprt_rdma *);
extern struct svc_xprt_class svc_rdma_class;
extern void svc_rdma_prep_reply_hdr(struct svc_rqst *);

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

/*
 * Returns the address of the first read chunk or <nul> if no read chunk is
 * present
 */
static inline struct rpcrdma_read_chunk *
svc_rdma_get_read_chunk(struct rpcrdma_msg *rmsgp)
{
    struct rpcrdma_read_chunk *ch =
        (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];

    if (ch->rc_discrim == 0)
        return NULL;

    return ch;
}

/*
 * Returns the address of the first read write array element or <nul> if no
 * write array list is present
 */
static inline struct rpcrdma_write_array *
svc_rdma_get_write_array(struct rpcrdma_msg *rmsgp)
{
    if (rmsgp->rm_body.rm_chunks[0] != 0
        || rmsgp->rm_body.rm_chunks[1] == 0)
        return NULL;

    return (struct rpcrdma_write_array *)&rmsgp->rm_body.rm_chunks[1];
}

/*
 * Returns the address of the first reply array element or <nul> if no
 * reply array is present
 */
static inline struct rpcrdma_write_array *
svc_rdma_get_reply_array(struct rpcrdma_msg *rmsgp)
{
    struct rpcrdma_read_chunk *rch;
    struct rpcrdma_write_array *wr_ary;
    struct rpcrdma_write_array *rp_ary;

    /* XXX: Need to fix when reply list may occur with read-list and/or
     * write list */
    if (rmsgp->rm_body.rm_chunks[0] != 0 ||
        rmsgp->rm_body.rm_chunks[1] != 0)
        return NULL;

    rch = svc_rdma_get_read_chunk(rmsgp);
    if (rch) {
        while (rch->rc_discrim)
            rch++;

        /* The reply list follows an empty write array located
         * at 'rc_position' here. The reply array is at rc_target.
         */
        rp_ary = (struct rpcrdma_write_array *)&rch->rc_target;

        goto found_it;
    }

    wr_ary = svc_rdma_get_write_array(rmsgp);
    if (wr_ary) {
        rp_ary = (struct rpcrdma_write_array *)
            &wr_ary->
            wc_array[ntohl(wr_ary->wc_nchunks)].wc_target.rs_length;

        goto found_it;
    }

    /* No read list, no write list */
    rp_ary = (struct rpcrdma_write_array *)
        &rmsgp->rm_body.rm_chunks[2];

 found_it:
    if (rp_ary->wc_discrim == 0)
        return NULL;

    return rp_ary;
}
#endif