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 <scsi/scsi_host.h>
  26 #include <scsi/scsi_device.h>
  27
  28 struct scsi_transport_template {
  29         /* the attribute containers */
  30         struct transport_container host_attrs;
  31         struct transport_container target_attrs;
  32         struct transport_container device_attrs;
  33
  34         /*
  35          * If set, called from sysfs and legacy procfs rescanning code.
  36          */
  37         int (*user_scan)(struct Scsi_Host *, uint, uint, uint);
  38
  39         /* The size of the specific transport attribute structure (a
  40          * space of this size will be left at the end of the
  41          * scsi_* structure */
  42         int     device_size;
  43         int     device_private_offset;
  44         int     target_size;
  45         int     target_private_offset;
  46         int     host_size;
  47         /* no private offset for the host; there's an alternative mechanism */
  48
  49         /*
  50          * True if the transport wants to use a host-based work-queue
  51          */
  52         unsigned int create_work_queue : 1;
  53
  54         /*
  55          * Allows a transport to override the default error handler.
  56          */
  57         void (* eh_strategy_handler)(struct Scsi_Host *);
  58
  59         /*
  60          * This is an optional routine that allows the transport to become
  61          * involved when a scsi io timer fires. The return value tells the
  62          * timer routine how to finish the io timeout handling:
  63          * EH_HANDLED:          I fixed the error, please complete the command
  64          * EH_RESET_TIMER:      I need more time, reset the timer and
  65          *                      begin counting again
  66          * EH_NOT_HANDLED       Begin normal error recovery
  67          */
  68         enum blk_eh_timer_return (*eh_timed_out)(struct scsi_cmnd *);
  69
  70         /*
  71          * Used as callback for the completion of i_t_nexus request
  72          * for target drivers.
  73          */
  74         int (* it_nexus_response)(struct Scsi_Host *, u64, int);
  75
  76         /*
  77          * Used as callback for the completion of task management
  78          * request for target drivers.
  79          */
  80         int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
  81 };
  82
  83 #define transport_class_to_shost(tc) \
  84         dev_to_shost((tc)->parent)
  85
  86
  87 /* Private area maintenance. The driver requested allocations come
  88  * directly after the transport class allocations (if any).  The idea
  89  * is that you *must* call these only once.  The code assumes that the
  90  * initial values are the ones the transport specific code requires */
  91 static inline void
  92 scsi_transport_reserve_target(struct scsi_transport_template * t, int space)
  93 {
  94         BUG_ON(t->target_private_offset != 0);
  95         t->target_private_offset = ALIGN(t->target_size, sizeof(void *));
  96         t->target_size = t->target_private_offset + space;
  97 }
  98 static inline void
  99 scsi_transport_reserve_device(struct scsi_transport_template * t, int space)
 100 {
 101         BUG_ON(t->device_private_offset != 0);
 102         t->device_private_offset = ALIGN(t->device_size, sizeof(void *));
 103         t->device_size = t->device_private_offset + space;
 104 }
 105 static inline void *
 106 scsi_transport_target_data(struct scsi_target *starget)
 107 {
 108         struct Scsi_Host *shost = dev_to_shost(&starget->dev);
 109         return (u8 *)starget->starget_data
 110                 + shost->transportt->target_private_offset;
 111
 112 }
 113 static inline void *
 114 scsi_transport_device_data(struct scsi_device *sdev)
 115 {
 116         struct Scsi_Host *shost = sdev->host;
 117         return (u8 *)sdev->sdev_data
 118                 + shost->transportt->device_private_offset;
 119 }
 120
 121 #endif /* SCSI_TRANSPORT_H */