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1/*
2 * SCSI device handler infrastruture.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the
6 * Free Software Foundation; either version 2 of the License, or (at your
7 * option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright IBM Corporation, 2007
19 * Authors:
20 * Chandra Seetharaman <sekharan@us.ibm.com>
21 * Mike Anderson <andmike@linux.vnet.ibm.com>
22 */
23
24#include <linux/slab.h>
25#include <linux/module.h>
26#include <scsi/scsi_dh.h>
27#include "scsi_priv.h"
28
29static DEFINE_SPINLOCK(list_lock);
30static LIST_HEAD(scsi_dh_list);
31
32struct scsi_dh_blist {
33 const char *vendor;
34 const char *model;
35 const char *driver;
36};
37
38static const struct scsi_dh_blist scsi_dh_blist[] = {
39 {"DGC", "RAID", "clariion" },
40 {"DGC", "DISK", "clariion" },
41 {"DGC", "VRAID", "clariion" },
42
43 {"COMPAQ", "MSA1000 VOLUME", "hp_sw" },
44 {"COMPAQ", "HSV110", "hp_sw" },
45 {"HP", "HSV100", "hp_sw"},
46 {"DEC", "HSG80", "hp_sw"},
47
48 {"IBM", "1722", "rdac", },
49 {"IBM", "1724", "rdac", },
50 {"IBM", "1726", "rdac", },
51 {"IBM", "1742", "rdac", },
52 {"IBM", "1745", "rdac", },
53 {"IBM", "1746", "rdac", },
54 {"IBM", "1813", "rdac", },
55 {"IBM", "1814", "rdac", },
56 {"IBM", "1815", "rdac", },
57 {"IBM", "1818", "rdac", },
58 {"IBM", "3526", "rdac", },
59 {"SGI", "TP9", "rdac", },
60 {"SGI", "IS", "rdac", },
61 {"STK", "OPENstorage D280", "rdac", },
62 {"STK", "FLEXLINE 380", "rdac", },
63 {"SUN", "CSM", "rdac", },
64 {"SUN", "LCSM100", "rdac", },
65 {"SUN", "STK6580_6780", "rdac", },
66 {"SUN", "SUN_6180", "rdac", },
67 {"SUN", "ArrayStorage", "rdac", },
68 {"DELL", "MD3", "rdac", },
69 {"NETAPP", "INF-01-00", "rdac", },
70 {"LSI", "INF-01-00", "rdac", },
71 {"ENGENIO", "INF-01-00", "rdac", },
72 {NULL, NULL, NULL },
73};
74
75static const char *
76scsi_dh_find_driver(struct scsi_device *sdev)
77{
78 const struct scsi_dh_blist *b;
79
80 if (scsi_device_tpgs(sdev))
81 return "alua";
82
83 for (b = scsi_dh_blist; b->vendor; b++) {
84 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
85 !strncmp(sdev->model, b->model, strlen(b->model))) {
86 return b->driver;
87 }
88 }
89 return NULL;
90}
91
92
93static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
94{
95 struct scsi_device_handler *tmp, *found = NULL;
96
97 spin_lock(&list_lock);
98 list_for_each_entry(tmp, &scsi_dh_list, list) {
99 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
100 found = tmp;
101 break;
102 }
103 }
104 spin_unlock(&list_lock);
105 return found;
106}
107
108static struct scsi_device_handler *scsi_dh_lookup(const char *name)
109{
110 struct scsi_device_handler *dh;
111
112 dh = __scsi_dh_lookup(name);
113 if (!dh) {
114 request_module("scsi_dh_%s", name);
115 dh = __scsi_dh_lookup(name);
116 }
117
118 return dh;
119}
120
121/*
122 * scsi_dh_handler_attach - Attach a device handler to a device
123 * @sdev - SCSI device the device handler should attach to
124 * @scsi_dh - The device handler to attach
125 */
126static int scsi_dh_handler_attach(struct scsi_device *sdev,
127 struct scsi_device_handler *scsi_dh)
128{
129 int error;
130
131 if (!try_module_get(scsi_dh->module))
132 return -EINVAL;
133
134 error = scsi_dh->attach(sdev);
135 if (error) {
136 sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
137 scsi_dh->name, error);
138 module_put(scsi_dh->module);
139 } else
140 sdev->handler = scsi_dh;
141
142 return error;
143}
144
145/*
146 * scsi_dh_handler_detach - Detach a device handler from a device
147 * @sdev - SCSI device the device handler should be detached from
148 */
149static void scsi_dh_handler_detach(struct scsi_device *sdev)
150{
151 sdev->handler->detach(sdev);
152 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
153 module_put(sdev->handler->module);
154}
155
156int scsi_dh_add_device(struct scsi_device *sdev)
157{
158 struct scsi_device_handler *devinfo = NULL;
159 const char *drv;
160 int err = 0;
161
162 drv = scsi_dh_find_driver(sdev);
163 if (drv)
164 devinfo = __scsi_dh_lookup(drv);
165 if (devinfo)
166 err = scsi_dh_handler_attach(sdev, devinfo);
167 return err;
168}
169
170void scsi_dh_release_device(struct scsi_device *sdev)
171{
172 if (sdev->handler)
173 scsi_dh_handler_detach(sdev);
174}
175
176/*
177 * scsi_register_device_handler - register a device handler personality
178 * module.
179 * @scsi_dh - device handler to be registered.
180 *
181 * Returns 0 on success, -EBUSY if handler already registered.
182 */
183int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
184{
185 if (__scsi_dh_lookup(scsi_dh->name))
186 return -EBUSY;
187
188 if (!scsi_dh->attach || !scsi_dh->detach)
189 return -EINVAL;
190
191 spin_lock(&list_lock);
192 list_add(&scsi_dh->list, &scsi_dh_list);
193 spin_unlock(&list_lock);
194
195 printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
196
197 return SCSI_DH_OK;
198}
199EXPORT_SYMBOL_GPL(scsi_register_device_handler);
200
201/*
202 * scsi_unregister_device_handler - register a device handler personality
203 * module.
204 * @scsi_dh - device handler to be unregistered.
205 *
206 * Returns 0 on success, -ENODEV if handler not registered.
207 */
208int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
209{
210 if (!__scsi_dh_lookup(scsi_dh->name))
211 return -ENODEV;
212
213 spin_lock(&list_lock);
214 list_del(&scsi_dh->list);
215 spin_unlock(&list_lock);
216 printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
217
218 return SCSI_DH_OK;
219}
220EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
221
222static struct scsi_device *get_sdev_from_queue(struct request_queue *q)
223{
224 struct scsi_device *sdev;
225 unsigned long flags;
226
227 spin_lock_irqsave(q->queue_lock, flags);
228 sdev = q->queuedata;
229 if (!sdev || !get_device(&sdev->sdev_gendev))
230 sdev = NULL;
231 spin_unlock_irqrestore(q->queue_lock, flags);
232
233 return sdev;
234}
235
236/*
237 * scsi_dh_activate - activate the path associated with the scsi_device
238 * corresponding to the given request queue.
239 * Returns immediately without waiting for activation to be completed.
240 * @q - Request queue that is associated with the scsi_device to be
241 * activated.
242 * @fn - Function to be called upon completion of the activation.
243 * Function fn is called with data (below) and the error code.
244 * Function fn may be called from the same calling context. So,
245 * do not hold the lock in the caller which may be needed in fn.
246 * @data - data passed to the function fn upon completion.
247 *
248 */
249int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
250{
251 struct scsi_device *sdev;
252 int err = SCSI_DH_NOSYS;
253
254 sdev = get_sdev_from_queue(q);
255 if (!sdev) {
256 if (fn)
257 fn(data, err);
258 return err;
259 }
260
261 if (!sdev->handler)
262 goto out_fn;
263 err = SCSI_DH_NOTCONN;
264 if (sdev->sdev_state == SDEV_CANCEL ||
265 sdev->sdev_state == SDEV_DEL)
266 goto out_fn;
267
268 err = SCSI_DH_DEV_OFFLINED;
269 if (sdev->sdev_state == SDEV_OFFLINE)
270 goto out_fn;
271
272 if (sdev->handler->activate)
273 err = sdev->handler->activate(sdev, fn, data);
274
275out_put_device:
276 put_device(&sdev->sdev_gendev);
277 return err;
278
279out_fn:
280 if (fn)
281 fn(data, err);
282 goto out_put_device;
283}
284EXPORT_SYMBOL_GPL(scsi_dh_activate);
285
286/*
287 * scsi_dh_set_params - set the parameters for the device as per the
288 * string specified in params.
289 * @q - Request queue that is associated with the scsi_device for
290 * which the parameters to be set.
291 * @params - parameters in the following format
292 * "no_of_params\0param1\0param2\0param3\0...\0"
293 * for example, string for 2 parameters with value 10 and 21
294 * is specified as "2\010\021\0".
295 */
296int scsi_dh_set_params(struct request_queue *q, const char *params)
297{
298 struct scsi_device *sdev;
299 int err = -SCSI_DH_NOSYS;
300
301 sdev = get_sdev_from_queue(q);
302 if (!sdev)
303 return err;
304
305 if (sdev->handler && sdev->handler->set_params)
306 err = sdev->handler->set_params(sdev, params);
307 put_device(&sdev->sdev_gendev);
308 return err;
309}
310EXPORT_SYMBOL_GPL(scsi_dh_set_params);
311
312/*
313 * scsi_dh_attach - Attach device handler
314 * @q - Request queue that is associated with the scsi_device
315 * the handler should be attached to
316 * @name - name of the handler to attach
317 */
318int scsi_dh_attach(struct request_queue *q, const char *name)
319{
320 struct scsi_device *sdev;
321 struct scsi_device_handler *scsi_dh;
322 int err = 0;
323
324 sdev = get_sdev_from_queue(q);
325 if (!sdev)
326 return -ENODEV;
327
328 scsi_dh = scsi_dh_lookup(name);
329 if (!scsi_dh) {
330 err = -EINVAL;
331 goto out_put_device;
332 }
333
334 if (sdev->handler) {
335 if (sdev->handler != scsi_dh)
336 err = -EBUSY;
337 goto out_put_device;
338 }
339
340 err = scsi_dh_handler_attach(sdev, scsi_dh);
341
342out_put_device:
343 put_device(&sdev->sdev_gendev);
344 return err;
345}
346EXPORT_SYMBOL_GPL(scsi_dh_attach);
347
348/*
349 * scsi_dh_attached_handler_name - Get attached device handler's name
350 * @q - Request queue that is associated with the scsi_device
351 * that may have a device handler attached
352 * @gfp - the GFP mask used in the kmalloc() call when allocating memory
353 *
354 * Returns name of attached handler, NULL if no handler is attached.
355 * Caller must take care to free the returned string.
356 */
357const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
358{
359 struct scsi_device *sdev;
360 const char *handler_name = NULL;
361
362 sdev = get_sdev_from_queue(q);
363 if (!sdev)
364 return NULL;
365
366 if (sdev->handler)
367 handler_name = kstrdup(sdev->handler->name, gfp);
368 put_device(&sdev->sdev_gendev);
369 return handler_name;
370}
371EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);