scsi_dh: Verify "dev" is a sdev before accessing it.
[linux-2.6] / drivers / scsi / device_handler / scsi_dh_hp_sw.c
1 /*
2  * Basic HP/COMPAQ MSA 1000 support. This is only needed if your HW cannot be
3  * upgraded.
4  *
5  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
6  * Copyright (C) 2006 Mike Christie
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2, or (at your option)
11  * any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; see the file COPYING.  If not, write to
20  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
21  */
22
23 #include <scsi/scsi.h>
24 #include <scsi/scsi_dbg.h>
25 #include <scsi/scsi_eh.h>
26 #include <scsi/scsi_dh.h>
27
28 #define HP_SW_NAME      "hp_sw"
29
30 #define HP_SW_TIMEOUT (60 * HZ)
31 #define HP_SW_RETRIES 3
32
33 struct hp_sw_dh_data {
34         unsigned char sense[SCSI_SENSE_BUFFERSIZE];
35         int retries;
36 };
37
38 static inline struct hp_sw_dh_data *get_hp_sw_data(struct scsi_device *sdev)
39 {
40         struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
41         BUG_ON(scsi_dh_data == NULL);
42         return ((struct hp_sw_dh_data *) scsi_dh_data->buf);
43 }
44
45 static int hp_sw_done(struct scsi_device *sdev)
46 {
47         struct hp_sw_dh_data *h = get_hp_sw_data(sdev);
48         struct scsi_sense_hdr sshdr;
49         int rc;
50
51         sdev_printk(KERN_INFO, sdev, "hp_sw_done\n");
52
53         rc = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE, &sshdr);
54         if (!rc)
55                 goto done;
56         switch (sshdr.sense_key) {
57         case NOT_READY:
58                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 3)) {
59                         rc = SCSI_DH_RETRY;
60                         h->retries++;
61                         break;
62                 }
63                 /* fall through */
64         default:
65                 h->retries++;
66                 rc = SCSI_DH_IMM_RETRY;
67         }
68
69 done:
70         if (rc == SCSI_DH_OK || rc == SCSI_DH_IO)
71                 h->retries = 0;
72         else if (h->retries > HP_SW_RETRIES) {
73                 h->retries = 0;
74                 rc = SCSI_DH_IO;
75         }
76         return rc;
77 }
78
79 static int hp_sw_activate(struct scsi_device *sdev)
80 {
81         struct hp_sw_dh_data *h = get_hp_sw_data(sdev);
82         struct request *req;
83         int ret = SCSI_DH_RES_TEMP_UNAVAIL;
84
85         req = blk_get_request(sdev->request_queue, WRITE, GFP_ATOMIC);
86         if (!req)
87                 goto done;
88
89         sdev_printk(KERN_INFO, sdev, "sending START_STOP.");
90
91         req->cmd_type = REQ_TYPE_BLOCK_PC;
92         req->cmd_flags |= REQ_FAILFAST;
93         req->cmd_len = COMMAND_SIZE(START_STOP);
94         memset(req->cmd, 0, MAX_COMMAND_SIZE);
95         req->cmd[0] = START_STOP;
96         req->cmd[4] = 1;        /* Start spin cycle */
97         req->timeout = HP_SW_TIMEOUT;
98         req->sense = h->sense;
99         memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
100         req->sense_len = 0;
101
102         ret = blk_execute_rq(req->q, NULL, req, 1);
103         if (!ret) /* SUCCESS */
104                 ret = hp_sw_done(sdev);
105         else
106                 ret = SCSI_DH_IO;
107 done:
108         return ret;
109 }
110
111 static const struct {
112         char *vendor;
113         char *model;
114 } hp_sw_dh_data_list[] = {
115         {"COMPAQ", "MSA"},
116         {"HP", "HSV"},
117         {"DEC", "HSG80"},
118         {NULL, NULL},
119 };
120
121 static int hp_sw_bus_notify(struct notifier_block *, unsigned long, void *);
122
123 static struct scsi_device_handler hp_sw_dh = {
124         .name           = HP_SW_NAME,
125         .module         = THIS_MODULE,
126         .nb.notifier_call = hp_sw_bus_notify,
127         .activate       = hp_sw_activate,
128 };
129
130 static int hp_sw_bus_notify(struct notifier_block *nb,
131                             unsigned long action, void *data)
132 {
133         struct device *dev = data;
134         struct scsi_device *sdev;
135         struct scsi_dh_data *scsi_dh_data;
136         int i, found = 0;
137         unsigned long flags;
138
139         if (!scsi_is_sdev_device(dev))
140                 return 0;
141
142         sdev = to_scsi_device(dev);
143
144         if (action == BUS_NOTIFY_ADD_DEVICE) {
145                 for (i = 0; hp_sw_dh_data_list[i].vendor; i++) {
146                         if (!strncmp(sdev->vendor, hp_sw_dh_data_list[i].vendor,
147                                      strlen(hp_sw_dh_data_list[i].vendor)) &&
148                             !strncmp(sdev->model, hp_sw_dh_data_list[i].model,
149                                      strlen(hp_sw_dh_data_list[i].model))) {
150                                 found = 1;
151                                 break;
152                         }
153                 }
154                 if (!found)
155                         goto out;
156
157                 scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
158                                 + sizeof(struct hp_sw_dh_data) , GFP_KERNEL);
159                 if (!scsi_dh_data) {
160                         sdev_printk(KERN_ERR, sdev, "Attach Failed %s.\n",
161                                     HP_SW_NAME);
162                         goto out;
163                 }
164
165                 scsi_dh_data->scsi_dh = &hp_sw_dh;
166                 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
167                 sdev->scsi_dh_data = scsi_dh_data;
168                 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
169                 try_module_get(THIS_MODULE);
170
171                 sdev_printk(KERN_NOTICE, sdev, "Attached %s.\n", HP_SW_NAME);
172         } else if (action == BUS_NOTIFY_DEL_DEVICE) {
173                 if (sdev->scsi_dh_data == NULL ||
174                                 sdev->scsi_dh_data->scsi_dh != &hp_sw_dh)
175                         goto out;
176
177                 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
178                 scsi_dh_data = sdev->scsi_dh_data;
179                 sdev->scsi_dh_data = NULL;
180                 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
181                 module_put(THIS_MODULE);
182
183                 sdev_printk(KERN_NOTICE, sdev, "Dettached %s.\n", HP_SW_NAME);
184
185                 kfree(scsi_dh_data);
186         }
187
188 out:
189         return 0;
190 }
191
192 static int __init hp_sw_init(void)
193 {
194         return scsi_register_device_handler(&hp_sw_dh);
195 }
196
197 static void __exit hp_sw_exit(void)
198 {
199         scsi_unregister_device_handler(&hp_sw_dh);
200 }
201
202 module_init(hp_sw_init);
203 module_exit(hp_sw_exit);
204
205 MODULE_DESCRIPTION("HP MSA 1000");
206 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu");
207 MODULE_LICENSE("GPL");