linux/drivers/nvme/host/fabrics.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * NVMe over Fabrics common host code.
   4 * Copyright (c) 2015-2016 HGST, a Western Digital Company.
   5 */
   6#ifndef _NVME_FABRICS_H
   7#define _NVME_FABRICS_H 1
   8
   9#include <linux/in.h>
  10#include <linux/inet.h>
  11
  12#define NVMF_MIN_QUEUE_SIZE     16
  13#define NVMF_MAX_QUEUE_SIZE     1024
  14#define NVMF_DEF_QUEUE_SIZE     128
  15#define NVMF_DEF_RECONNECT_DELAY        10
  16/* default to 600 seconds of reconnect attempts before giving up */
  17#define NVMF_DEF_CTRL_LOSS_TMO          600
  18/* default is -1: the fail fast mechanism is disabled  */
  19#define NVMF_DEF_FAIL_FAST_TMO          -1
  20
  21/*
  22 * Reserved one command for internal usage.  This command is used for sending
  23 * the connect command, as well as for the keep alive command on the admin
  24 * queue once live.
  25 */
  26#define NVMF_RESERVED_TAGS      1
  27
  28/*
  29 * Define a host as seen by the target.  We allocate one at boot, but also
  30 * allow the override it when creating controllers.  This is both to provide
  31 * persistence of the Host NQN over multiple boots, and to allow using
  32 * multiple ones, for example in a container scenario.  Because we must not
  33 * use different Host NQNs with the same Host ID we generate a Host ID and
  34 * use this structure to keep track of the relation between the two.
  35 */
  36struct nvmf_host {
  37        struct kref             ref;
  38        struct list_head        list;
  39        char                    nqn[NVMF_NQN_SIZE];
  40        uuid_t                  id;
  41};
  42
  43/**
  44 * enum nvmf_parsing_opts - used to define the sysfs parsing options used.
  45 */
  46enum {
  47        NVMF_OPT_ERR            = 0,
  48        NVMF_OPT_TRANSPORT      = 1 << 0,
  49        NVMF_OPT_NQN            = 1 << 1,
  50        NVMF_OPT_TRADDR         = 1 << 2,
  51        NVMF_OPT_TRSVCID        = 1 << 3,
  52        NVMF_OPT_QUEUE_SIZE     = 1 << 4,
  53        NVMF_OPT_NR_IO_QUEUES   = 1 << 5,
  54        NVMF_OPT_TL_RETRY_COUNT = 1 << 6,
  55        NVMF_OPT_KATO           = 1 << 7,
  56        NVMF_OPT_HOSTNQN        = 1 << 8,
  57        NVMF_OPT_RECONNECT_DELAY = 1 << 9,
  58        NVMF_OPT_HOST_TRADDR    = 1 << 10,
  59        NVMF_OPT_CTRL_LOSS_TMO  = 1 << 11,
  60        NVMF_OPT_HOST_ID        = 1 << 12,
  61        NVMF_OPT_DUP_CONNECT    = 1 << 13,
  62        NVMF_OPT_DISABLE_SQFLOW = 1 << 14,
  63        NVMF_OPT_HDR_DIGEST     = 1 << 15,
  64        NVMF_OPT_DATA_DIGEST    = 1 << 16,
  65        NVMF_OPT_NR_WRITE_QUEUES = 1 << 17,
  66        NVMF_OPT_NR_POLL_QUEUES = 1 << 18,
  67        NVMF_OPT_TOS            = 1 << 19,
  68        NVMF_OPT_FAIL_FAST_TMO  = 1 << 20,
  69        NVMF_OPT_HOST_IFACE     = 1 << 21,
  70};
  71
  72/**
  73 * struct nvmf_ctrl_options - Used to hold the options specified
  74 *                            with the parsing opts enum.
  75 * @mask:       Used by the fabrics library to parse through sysfs options
  76 *              on adding a NVMe controller.
  77 * @transport:  Holds the fabric transport "technology name" (for a lack of
  78 *              better description) that will be used by an NVMe controller
  79 *              being added.
  80 * @subsysnqn:  Hold the fully qualified NQN subystem name (format defined
  81 *              in the NVMe specification, "NVMe Qualified Names").
  82 * @traddr:     The transport-specific TRADDR field for a port on the
  83 *              subsystem which is adding a controller.
  84 * @trsvcid:    The transport-specific TRSVCID field for a port on the
  85 *              subsystem which is adding a controller.
  86 * @host_traddr: A transport-specific field identifying the NVME host port
  87 *     to use for the connection to the controller.
  88 * @host_iface: A transport-specific field identifying the NVME host
  89 *     interface to use for the connection to the controller.
  90 * @queue_size: Number of IO queue elements.
  91 * @nr_io_queues: Number of controller IO queues that will be established.
  92 * @reconnect_delay: Time between two consecutive reconnect attempts.
  93 * @discovery_nqn: indicates if the subsysnqn is the well-known discovery NQN.
  94 * @kato:       Keep-alive timeout.
  95 * @host:       Virtual NVMe host, contains the NQN and Host ID.
  96 * @max_reconnects: maximum number of allowed reconnect attempts before removing
  97 *              the controller, (-1) means reconnect forever, zero means remove
  98 *              immediately;
  99 * @disable_sqflow: disable controller sq flow control
 100 * @hdr_digest: generate/verify header digest (TCP)
 101 * @data_digest: generate/verify data digest (TCP)
 102 * @nr_write_queues: number of queues for write I/O
 103 * @nr_poll_queues: number of queues for polling I/O
 104 * @tos: type of service
 105 * @fast_io_fail_tmo: Fast I/O fail timeout in seconds
 106 */
 107struct nvmf_ctrl_options {
 108        unsigned                mask;
 109        char                    *transport;
 110        char                    *subsysnqn;
 111        char                    *traddr;
 112        char                    *trsvcid;
 113        char                    *host_traddr;
 114        char                    *host_iface;
 115        size_t                  queue_size;
 116        unsigned int            nr_io_queues;
 117        unsigned int            reconnect_delay;
 118        bool                    discovery_nqn;
 119        bool                    duplicate_connect;
 120        unsigned int            kato;
 121        struct nvmf_host        *host;
 122        int                     max_reconnects;
 123        bool                    disable_sqflow;
 124        bool                    hdr_digest;
 125        bool                    data_digest;
 126        unsigned int            nr_write_queues;
 127        unsigned int            nr_poll_queues;
 128        int                     tos;
 129        int                     fast_io_fail_tmo;
 130};
 131
 132/*
 133 * struct nvmf_transport_ops - used to register a specific
 134 *                             fabric implementation of NVMe fabrics.
 135 * @entry:              Used by the fabrics library to add the new
 136 *                      registration entry to its linked-list internal tree.
 137 * @module:             Transport module reference
 138 * @name:               Name of the NVMe fabric driver implementation.
 139 * @required_opts:      sysfs command-line options that must be specified
 140 *                      when adding a new NVMe controller.
 141 * @allowed_opts:       sysfs command-line options that can be specified
 142 *                      when adding a new NVMe controller.
 143 * @create_ctrl():      function pointer that points to a non-NVMe
 144 *                      implementation-specific fabric technology
 145 *                      that would go into starting up that fabric
 146 *                      for the purpose of conneciton to an NVMe controller
 147 *                      using that fabric technology.
 148 *
 149 * Notes:
 150 *      1. At minimum, 'required_opts' and 'allowed_opts' should
 151 *         be set to the same enum parsing options defined earlier.
 152 *      2. create_ctrl() must be defined (even if it does nothing)
 153 *      3. struct nvmf_transport_ops must be statically allocated in the
 154 *         modules .bss section so that a pure module_get on @module
 155 *         prevents the memory from beeing freed.
 156 */
 157struct nvmf_transport_ops {
 158        struct list_head        entry;
 159        struct module           *module;
 160        const char              *name;
 161        int                     required_opts;
 162        int                     allowed_opts;
 163        struct nvme_ctrl        *(*create_ctrl)(struct device *dev,
 164                                        struct nvmf_ctrl_options *opts);
 165};
 166
 167static inline bool
 168nvmf_ctlr_matches_baseopts(struct nvme_ctrl *ctrl,
 169                        struct nvmf_ctrl_options *opts)
 170{
 171        if (ctrl->state == NVME_CTRL_DELETING ||
 172            ctrl->state == NVME_CTRL_DEAD ||
 173            strcmp(opts->subsysnqn, ctrl->opts->subsysnqn) ||
 174            strcmp(opts->host->nqn, ctrl->opts->host->nqn) ||
 175            memcmp(&opts->host->id, &ctrl->opts->host->id, sizeof(uuid_t)))
 176                return false;
 177
 178        return true;
 179}
 180
 181int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val);
 182int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val);
 183int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val);
 184int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl);
 185int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid);
 186int nvmf_register_transport(struct nvmf_transport_ops *ops);
 187void nvmf_unregister_transport(struct nvmf_transport_ops *ops);
 188void nvmf_free_options(struct nvmf_ctrl_options *opts);
 189int nvmf_get_address(struct nvme_ctrl *ctrl, char *buf, int size);
 190bool nvmf_should_reconnect(struct nvme_ctrl *ctrl);
 191bool nvmf_ip_options_match(struct nvme_ctrl *ctrl,
 192                struct nvmf_ctrl_options *opts);
 193
 194#endif /* _NVME_FABRICS_H */
 195
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