drivers/nvme/host/fabrics.h

   1 /*
   2  * NVMe over Fabrics common host code.
   3  * Copyright (c) 2015-2016 HGST, a Western Digital Company.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  */
  14 #ifndef _NVME_FABRICS_H
  15 #define _NVME_FABRICS_H 1
  16
  17 #include <linux/in.h>
  18 #include <linux/inet.h>
  19
  20 #define NVMF_MIN_QUEUE_SIZE     16
  21 #define NVMF_MAX_QUEUE_SIZE     1024
  22 #define NVMF_DEF_QUEUE_SIZE     128
  23 #define NVMF_DEF_RECONNECT_DELAY        10
  24 /* default to 600 seconds of reconnect attempts before giving up */
  25 #define NVMF_DEF_CTRL_LOSS_TMO          600
  26
  27 /*
  28  * Define a host as seen by the target.  We allocate one at boot, but also
  29  * allow the override it when creating controllers.  This is both to provide
  30  * persistence of the Host NQN over multiple boots, and to allow using
  31  * multiple ones, for example in a container scenario.  Because we must not
  32  * use different Host NQNs with the same Host ID we generate a Host ID and
  33  * use this structure to keep track of the relation between the two.
  34  */
  35 struct nvmf_host {
  36         struct kref             ref;
  37         struct list_head        list;
  38         char                    nqn[NVMF_NQN_SIZE];
  39         uuid_t                  id;
  40 };
  41
  42 /**
  43  * enum nvmf_parsing_opts - used to define the sysfs parsing options used.
  44  */
  45 enum {
  46         NVMF_OPT_ERR            = 0,
  47         NVMF_OPT_TRANSPORT      = 1 << 0,
  48         NVMF_OPT_NQN            = 1 << 1,
  49         NVMF_OPT_TRADDR         = 1 << 2,
  50         NVMF_OPT_TRSVCID        = 1 << 3,
  51         NVMF_OPT_QUEUE_SIZE     = 1 << 4,
  52         NVMF_OPT_NR_IO_QUEUES   = 1 << 5,
  53         NVMF_OPT_TL_RETRY_COUNT = 1 << 6,
  54         NVMF_OPT_KATO           = 1 << 7,
  55         NVMF_OPT_HOSTNQN        = 1 << 8,
  56         NVMF_OPT_RECONNECT_DELAY = 1 << 9,
  57         NVMF_OPT_HOST_TRADDR    = 1 << 10,
  58         NVMF_OPT_CTRL_LOSS_TMO  = 1 << 11,
  59         NVMF_OPT_HOST_ID        = 1 << 12,
  60         NVMF_OPT_DUP_CONNECT    = 1 << 13,
  61 };
  62
  63 /**
  64  * struct nvmf_ctrl_options - Used to hold the options specified
  65  *                            with the parsing opts enum.
  66  * @mask:       Used by the fabrics library to parse through sysfs options
  67  *              on adding a NVMe controller.
  68  * @transport:  Holds the fabric transport "technology name" (for a lack of
  69  *              better description) that will be used by an NVMe controller
  70  *              being added.
  71  * @subsysnqn:  Hold the fully qualified NQN subystem name (format defined
  72  *              in the NVMe specification, "NVMe Qualified Names").
  73  * @traddr:     The transport-specific TRADDR field for a port on the
  74  *              subsystem which is adding a controller.
  75  * @trsvcid:    The transport-specific TRSVCID field for a port on the
  76  *              subsystem which is adding a controller.
  77  * @host_traddr: A transport-specific field identifying the NVME host port
  78  *              to use for the connection to the controller.
  79  * @queue_size: Number of IO queue elements.
  80  * @nr_io_queues: Number of controller IO queues that will be established.
  81  * @reconnect_delay: Time between two consecutive reconnect attempts.
  82  * @discovery_nqn: indicates if the subsysnqn is the well-known discovery NQN.
  83  * @kato:       Keep-alive timeout.
  84  * @host:       Virtual NVMe host, contains the NQN and Host ID.
  85  * @max_reconnects: maximum number of allowed reconnect attempts before removing
  86  *              the controller, (-1) means reconnect forever, zero means remove
  87  *              immediately;
  88  */
  89 struct nvmf_ctrl_options {
  90         unsigned                mask;
  91         char                    *transport;
  92         char                    *subsysnqn;
  93         char                    *traddr;
  94         char                    *trsvcid;
  95         char                    *host_traddr;
  96         size_t                  queue_size;
  97         unsigned int            nr_io_queues;
  98         unsigned int            reconnect_delay;
  99         bool                    discovery_nqn;
 100         bool                    duplicate_connect;
 101         unsigned int            kato;
 102         struct nvmf_host        *host;
 103         int                     max_reconnects;
 104 };
 105
 106 /*
 107  * struct nvmf_transport_ops - used to register a specific
 108  *                             fabric implementation of NVMe fabrics.
 109  * @entry:              Used by the fabrics library to add the new
 110  *                      registration entry to its linked-list internal tree.
 111  * @name:               Name of the NVMe fabric driver implementation.
 112  * @required_opts:      sysfs command-line options that must be specified
 113  *                      when adding a new NVMe controller.
 114  * @allowed_opts:       sysfs command-line options that can be specified
 115  *                      when adding a new NVMe controller.
 116  * @create_ctrl():      function pointer that points to a non-NVMe
 117  *                      implementation-specific fabric technology
 118  *                      that would go into starting up that fabric
 119  *                      for the purpose of conneciton to an NVMe controller
 120  *                      using that fabric technology.
 121  *
 122  * Notes:
 123  *      1. At minimum, 'required_opts' and 'allowed_opts' should
 124  *         be set to the same enum parsing options defined earlier.
 125  *      2. create_ctrl() must be defined (even if it does nothing)
 126  */
 127 struct nvmf_transport_ops {
 128         struct list_head        entry;
 129         const char              *name;
 130         int                     required_opts;
 131         int                     allowed_opts;
 132         struct nvme_ctrl        *(*create_ctrl)(struct device *dev,
 133                                         struct nvmf_ctrl_options *opts);
 134 };
 135
 136 static inline bool
 137 nvmf_ctlr_matches_baseopts(struct nvme_ctrl *ctrl,
 138                         struct nvmf_ctrl_options *opts)
 139 {
 140         if (strcmp(opts->subsysnqn, ctrl->opts->subsysnqn) ||
 141             strcmp(opts->host->nqn, ctrl->opts->host->nqn) ||
 142             memcmp(&opts->host->id, &ctrl->opts->host->id, sizeof(uuid_t)))
 143                 return false;
 144
 145         return true;
 146 }
 147
 148 int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val);
 149 int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val);
 150 int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val);
 151 int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl);
 152 int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid);
 153 int nvmf_register_transport(struct nvmf_transport_ops *ops);
 154 void nvmf_unregister_transport(struct nvmf_transport_ops *ops);
 155 void nvmf_free_options(struct nvmf_ctrl_options *opts);
 156 int nvmf_get_address(struct nvme_ctrl *ctrl, char *buf, int size);
 157 bool nvmf_should_reconnect(struct nvme_ctrl *ctrl);
 158
 159 static inline blk_status_t nvmf_check_init_req(struct nvme_ctrl *ctrl,
 160                 struct request *rq)
 161 {
 162         struct nvme_command *cmd = nvme_req(rq)->cmd;
 163
 164         /*
 165          * We cannot accept any other command until the connect command has
 166          * completed, so only allow connect to pass.
 167          */
 168         if (!blk_rq_is_passthrough(rq) ||
 169             cmd->common.opcode != nvme_fabrics_command ||
 170             cmd->fabrics.fctype != nvme_fabrics_type_connect) {
 171                 /*
 172                  * Reconnecting state means transport disruption, which can take
 173                  * a long time and even might fail permanently, fail fast to
 174                  * give upper layers a chance to failover.
 175                  * Deleting state means that the ctrl will never accept commands
 176                  * again, fail it permanently.
 177                  */
 178                 if (ctrl->state == NVME_CTRL_RECONNECTING ||
 179                     ctrl->state == NVME_CTRL_DELETING) {
 180                         nvme_req(rq)->status = NVME_SC_ABORT_REQ;
 181                         return BLK_STS_IOERR;
 182                 }
 183                 return BLK_STS_RESOURCE; /* try again later */
 184         }
 185
 186         return BLK_STS_OK;
 187 }
 188
 189 #endif /* _NVME_FABRICS_H */