include/scsi/scsi_transport.h

   1 /*
   2  *  Transport specific attributes.
   3  *
   4  *  Copyright (c) 2003 Silicon Graphics, Inc.  All rights reserved.
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #ifndef SCSI_TRANSPORT_H
  21 #define SCSI_TRANSPORT_H
  22
  23 #include <linux/transport_class.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/bug.h>
  26 #include <scsi/scsi_host.h>
  27 #include <scsi/scsi_device.h>
  28
  29 struct scsi_transport_template {
  30         /* the attribute containers */
  31         struct transport_container host_attrs;
  32         struct transport_container target_attrs;
  33         struct transport_container device_attrs;
  34
  35         /*
  36          * If set, called from sysfs and legacy procfs rescanning code.
  37          */
  38         int (*user_scan)(struct Scsi_Host *, uint, uint, u64);
  39
  40         /* The size of the specific transport attribute structure (a
  41          * space of this size will be left at the end of the
  42          * scsi_* structure */
  43         int     device_size;
  44         int     device_private_offset;
  45         int     target_size;
  46         int     target_private_offset;
  47         int     host_size;
  48         /* no private offset for the host; there's an alternative mechanism */
  49
  50         /*
  51          * True if the transport wants to use a host-based work-queue
  52          */
  53         unsigned int create_work_queue : 1;
  54
  55         /*
  56          * Allows a transport to override the default error handler.
  57          */
  58         void (* eh_strategy_handler)(struct Scsi_Host *);
  59
  60         /*
  61          * This is an optional routine that allows the transport to become
  62          * involved when a scsi io timer fires. The return value tells the
  63          * timer routine how to finish the io timeout handling:
  64          * EH_HANDLED:          I fixed the error, please complete the command
  65          * EH_RESET_TIMER:      I need more time, reset the timer and
  66          *                      begin counting again
  67          * EH_NOT_HANDLED       Begin normal error recovery
  68          */
  69         enum blk_eh_timer_return (*eh_timed_out)(struct scsi_cmnd *);
  70
  71         /*
  72          * Used as callback for the completion of i_t_nexus request
  73          * for target drivers.
  74          */
  75         int (* it_nexus_response)(struct Scsi_Host *, u64, int);
  76
  77         /*
  78          * Used as callback for the completion of task management
  79          * request for target drivers.
  80          */
  81         int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
  82 };
  83
  84 #define transport_class_to_shost(tc) \
  85         dev_to_shost((tc)->parent)
  86
  87
  88 /* Private area maintenance. The driver requested allocations come
  89  * directly after the transport class allocations (if any).  The idea
  90  * is that you *must* call these only once.  The code assumes that the
  91  * initial values are the ones the transport specific code requires */
  92 static inline void
  93 scsi_transport_reserve_target(struct scsi_transport_template * t, int space)
  94 {
  95         BUG_ON(t->target_private_offset != 0);
  96         t->target_private_offset = ALIGN(t->target_size, sizeof(void *));
  97         t->target_size = t->target_private_offset + space;
  98 }
  99 static inline void
 100 scsi_transport_reserve_device(struct scsi_transport_template * t, int space)
 101 {
 102         BUG_ON(t->device_private_offset != 0);
 103         t->device_private_offset = ALIGN(t->device_size, sizeof(void *));
 104         t->device_size = t->device_private_offset + space;
 105 }
 106 static inline void *
 107 scsi_transport_target_data(struct scsi_target *starget)
 108 {
 109         struct Scsi_Host *shost = dev_to_shost(&starget->dev);
 110         return (u8 *)starget->starget_data
 111                 + shost->transportt->target_private_offset;
 112
 113 }
 114 static inline void *
 115 scsi_transport_device_data(struct scsi_device *sdev)
 116 {
 117         struct Scsi_Host *shost = sdev->host;
 118         return (u8 *)sdev->sdev_data
 119                 + shost->transportt->device_private_offset;
 120 }
 121
 122 #endif /* SCSI_TRANSPORT_H */