Root/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
28struct 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 */
91static inline void
92scsi_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}
98static inline void
99scsi_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}
105static inline void *
106scsi_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}
113static inline void *
114scsi_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 */
122

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