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