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 <scsi/scsi_host.h>
  25
  26 struct scsi_transport_template {
  27         /* the attribute containers */
  28         struct transport_container host_attrs;
  29         struct transport_container target_attrs;
  30         struct transport_container device_attrs;
  31
  32         /*
  33          * If set, called from sysfs and legacy procfs rescanning code.
  34          */
  35         int (*user_scan)(struct Scsi_Host *, uint, uint, uint);
  36
  37         /* The size of the specific transport attribute structure (a
  38          * space of this size will be left at the end of the
  39          * scsi_* structure */
  40         int     device_size;
  41         int     device_private_offset;
  42         int     target_size;
  43         int     target_private_offset;
  44         int     host_size;
  45         /* no private offset for the host; there's an alternative mechanism */
  46
  47         /*
  48          * True if the transport wants to use a host-based work-queue
  49          */
  50         unsigned int create_work_queue : 1;
  51
  52         /*
  53          * Allows a transport to override the default error handler.
  54          */
  55         void (* eh_strategy_handler)(struct Scsi_Host *);
  56
  57         /*
  58          * This is an optional routine that allows the transport to become
  59          * involved when a scsi io timer fires. The return value tells the
  60          * timer routine how to finish the io timeout handling:
  61          * EH_HANDLED:          I fixed the error, please complete the command
  62          * EH_RESET_TIMER:      I need more time, reset the timer and
  63          *                      begin counting again
  64          * EH_NOT_HANDLED       Begin normal error recovery
  65          */
  66         enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
  67 };
  68
  69 #define transport_class_to_shost(tc) \
  70         dev_to_shost((tc)->dev)
  71
  72
  73 /* Private area maintenance. The driver requested allocations come
  74  * directly after the transport class allocations (if any).  The idea
  75  * is that you *must* call these only once.  The code assumes that the
  76  * initial values are the ones the transport specific code requires */
  77 static inline void
  78 scsi_transport_reserve_target(struct scsi_transport_template * t, int space)
  79 {
  80         BUG_ON(t->target_private_offset != 0);
  81         t->target_private_offset = ALIGN(t->target_size, sizeof(void *));
  82         t->target_size = t->target_private_offset + space;
  83 }
  84 static inline void
  85 scsi_transport_reserve_device(struct scsi_transport_template * t, int space)
  86 {
  87         BUG_ON(t->device_private_offset != 0);
  88         t->device_private_offset = ALIGN(t->device_size, sizeof(void *));
  89         t->device_size = t->device_private_offset + space;
  90 }
  91 static inline void *
  92 scsi_transport_target_data(struct scsi_target *starget)
  93 {
  94         struct Scsi_Host *shost = dev_to_shost(&starget->dev);
  95         return (u8 *)starget->starget_data
  96                 + shost->transportt->target_private_offset;
  97
  98 }
  99 static inline void *
 100 scsi_transport_device_data(struct scsi_device *sdev)
 101 {
 102         struct Scsi_Host *shost = sdev->host;
 103         return (u8 *)sdev->sdev_data
 104                 + shost->transportt->device_private_offset;
 105 }
 106
 107 #endif /* SCSI_TRANSPORT_H */