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", "emc" },
40 {"DGC", "DISK", "emc" },
41 {"DGC", "VRAID", "emc" },
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 {"IBM", "3542", "rdac", },
60 {"IBM", "3552", "rdac", },
61 {"SGI", "TP9300", "rdac", },
62 {"SGI", "TP9400", "rdac", },
63 {"SGI", "TP9500", "rdac", },
64 {"SGI", "TP9700", "rdac", },
65 {"SGI", "IS", "rdac", },
66 {"STK", "OPENstorage", "rdac", },
67 {"STK", "FLEXLINE 380", "rdac", },
68 {"STK", "BladeCtlr", "rdac", },
69 {"SUN", "CSM", "rdac", },
70 {"SUN", "LCSM100", "rdac", },
71 {"SUN", "STK6580_6780", "rdac", },
72 {"SUN", "SUN_6180", "rdac", },
73 {"SUN", "ArrayStorage", "rdac", },
74 {"DELL", "MD3", "rdac", },
75 {"NETAPP", "INF-01-00", "rdac", },
76 {"LSI", "INF-01-00", "rdac", },
77 {"ENGENIO", "INF-01-00", "rdac", },
78 {NULL, NULL, NULL },
79};
80
81static const char *
82scsi_dh_find_driver(struct scsi_device *sdev)
83{
84 const struct scsi_dh_blist *b;
85
86 if (scsi_device_tpgs(sdev))
87 return "alua";
88
89 for (b = scsi_dh_blist; b->vendor; b++) {
90 if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
91 !strncmp(sdev->model, b->model, strlen(b->model))) {
92 return b->driver;
93 }
94 }
95 return NULL;
96}
97
98
99static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
100{
101 struct scsi_device_handler *tmp, *found = NULL;
102
103 spin_lock(&list_lock);
104 list_for_each_entry(tmp, &scsi_dh_list, list) {
105 if (!strncmp(tmp->name, name, strlen(tmp->name))) {
106 found = tmp;
107 break;
108 }
109 }
110 spin_unlock(&list_lock);
111 return found;
112}
113
114static struct scsi_device_handler *scsi_dh_lookup(const char *name)
115{
116 struct scsi_device_handler *dh;
117
118 if (!name || strlen(name) == 0)
119 return NULL;
120
121 dh = __scsi_dh_lookup(name);
122 if (!dh) {
123 request_module("scsi_dh_%s", name);
124 dh = __scsi_dh_lookup(name);
125 }
126
127 return dh;
128}
129
130/*
131 * scsi_dh_handler_attach - Attach a device handler to a device
132 * @sdev - SCSI device the device handler should attach to
133 * @scsi_dh - The device handler to attach
134 */
135static int scsi_dh_handler_attach(struct scsi_device *sdev,
136 struct scsi_device_handler *scsi_dh)
137{
138 int error, ret = 0;
139
140 if (!try_module_get(scsi_dh->module))
141 return -EINVAL;
142
143 error = scsi_dh->attach(sdev);
144 if (error != SCSI_DH_OK) {
145 switch (error) {
146 case SCSI_DH_NOMEM:
147 ret = -ENOMEM;
148 break;
149 case SCSI_DH_RES_TEMP_UNAVAIL:
150 ret = -EAGAIN;
151 break;
152 case SCSI_DH_DEV_UNSUPP:
153 case SCSI_DH_NOSYS:
154 ret = -ENODEV;
155 break;
156 default:
157 ret = -EINVAL;
158 break;
159 }
160 if (ret != -ENODEV)
161 sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
162 scsi_dh->name, error);
163 module_put(scsi_dh->module);
164 } else
165 sdev->handler = scsi_dh;
166
167 return ret;
168}
169
170/*
171 * scsi_dh_handler_detach - Detach a device handler from a device
172 * @sdev - SCSI device the device handler should be detached from
173 */
174static void scsi_dh_handler_detach(struct scsi_device *sdev)
175{
176 sdev->handler->detach(sdev);
177 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
178 module_put(sdev->handler->module);
179}
180
181void scsi_dh_add_device(struct scsi_device *sdev)
182{
183 struct scsi_device_handler *devinfo = NULL;
184 const char *drv;
185
186 drv = scsi_dh_find_driver(sdev);
187 if (drv)
188 devinfo = __scsi_dh_lookup(drv);
189 /*
190 * device_handler is optional, so ignore errors
191 * from scsi_dh_handler_attach()
192 */
193 if (devinfo)
194 (void)scsi_dh_handler_attach(sdev, devinfo);
195}
196
197void scsi_dh_release_device(struct scsi_device *sdev)
198{
199 if (sdev->handler)
200 scsi_dh_handler_detach(sdev);
201}
202
203/*
204 * scsi_register_device_handler - register a device handler personality
205 * module.
206 * @scsi_dh - device handler to be registered.
207 *
208 * Returns 0 on success, -EBUSY if handler already registered.
209 */
210int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
211{
212 if (__scsi_dh_lookup(scsi_dh->name))
213 return -EBUSY;
214
215 if (!scsi_dh->attach || !scsi_dh->detach)
216 return -EINVAL;
217
218 spin_lock(&list_lock);
219 list_add(&scsi_dh->list, &scsi_dh_list);
220 spin_unlock(&list_lock);
221
222 printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);
223
224 return SCSI_DH_OK;
225}
226EXPORT_SYMBOL_GPL(scsi_register_device_handler);
227
228/*
229 * scsi_unregister_device_handler - register a device handler personality
230 * module.
231 * @scsi_dh - device handler to be unregistered.
232 *
233 * Returns 0 on success, -ENODEV if handler not registered.
234 */
235int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
236{
237 if (!__scsi_dh_lookup(scsi_dh->name))
238 return -ENODEV;
239
240 spin_lock(&list_lock);
241 list_del(&scsi_dh->list);
242 spin_unlock(&list_lock);
243 printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);
244
245 return SCSI_DH_OK;
246}
247EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
248
249/*
250 * scsi_dh_activate - activate the path associated with the scsi_device
251 * corresponding to the given request queue.
252 * Returns immediately without waiting for activation to be completed.
253 * @q - Request queue that is associated with the scsi_device to be
254 * activated.
255 * @fn - Function to be called upon completion of the activation.
256 * Function fn is called with data (below) and the error code.
257 * Function fn may be called from the same calling context. So,
258 * do not hold the lock in the caller which may be needed in fn.
259 * @data - data passed to the function fn upon completion.
260 *
261 */
262int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
263{
264 struct scsi_device *sdev;
265 int err = SCSI_DH_NOSYS;
266
267 sdev = scsi_device_from_queue(q);
268 if (!sdev) {
269 if (fn)
270 fn(data, err);
271 return err;
272 }
273
274 if (!sdev->handler)
275 goto out_fn;
276 err = SCSI_DH_NOTCONN;
277 if (sdev->sdev_state == SDEV_CANCEL ||
278 sdev->sdev_state == SDEV_DEL)
279 goto out_fn;
280
281 err = SCSI_DH_DEV_OFFLINED;
282 if (sdev->sdev_state == SDEV_OFFLINE)
283 goto out_fn;
284
285 if (sdev->handler->activate)
286 err = sdev->handler->activate(sdev, fn, data);
287
288out_put_device:
289 put_device(&sdev->sdev_gendev);
290 return err;
291
292out_fn:
293 if (fn)
294 fn(data, err);
295 goto out_put_device;
296}
297EXPORT_SYMBOL_GPL(scsi_dh_activate);
298
299/*
300 * scsi_dh_set_params - set the parameters for the device as per the
301 * string specified in params.
302 * @q - Request queue that is associated with the scsi_device for
303 * which the parameters to be set.
304 * @params - parameters in the following format
305 * "no_of_params\0param1\0param2\0param3\0...\0"
306 * for example, string for 2 parameters with value 10 and 21
307 * is specified as "2\010\021\0".
308 */
309int scsi_dh_set_params(struct request_queue *q, const char *params)
310{
311 struct scsi_device *sdev;
312 int err = -SCSI_DH_NOSYS;
313
314 sdev = scsi_device_from_queue(q);
315 if (!sdev)
316 return err;
317
318 if (sdev->handler && sdev->handler->set_params)
319 err = sdev->handler->set_params(sdev, params);
320 put_device(&sdev->sdev_gendev);
321 return err;
322}
323EXPORT_SYMBOL_GPL(scsi_dh_set_params);
324
325/*
326 * scsi_dh_attach - Attach device handler
327 * @q - Request queue that is associated with the scsi_device
328 * the handler should be attached to
329 * @name - name of the handler to attach
330 */
331int scsi_dh_attach(struct request_queue *q, const char *name)
332{
333 struct scsi_device *sdev;
334 struct scsi_device_handler *scsi_dh;
335 int err = 0;
336
337 sdev = scsi_device_from_queue(q);
338 if (!sdev)
339 return -ENODEV;
340
341 scsi_dh = scsi_dh_lookup(name);
342 if (!scsi_dh) {
343 err = -EINVAL;
344 goto out_put_device;
345 }
346
347 if (sdev->handler) {
348 if (sdev->handler != scsi_dh)
349 err = -EBUSY;
350 goto out_put_device;
351 }
352
353 err = scsi_dh_handler_attach(sdev, scsi_dh);
354
355out_put_device:
356 put_device(&sdev->sdev_gendev);
357 return err;
358}
359EXPORT_SYMBOL_GPL(scsi_dh_attach);
360
361/*
362 * scsi_dh_attached_handler_name - Get attached device handler's name
363 * @q - Request queue that is associated with the scsi_device
364 * that may have a device handler attached
365 * @gfp - the GFP mask used in the kmalloc() call when allocating memory
366 *
367 * Returns name of attached handler, NULL if no handler is attached.
368 * Caller must take care to free the returned string.
369 */
370const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
371{
372 struct scsi_device *sdev;
373 const char *handler_name = NULL;
374
375 sdev = scsi_device_from_queue(q);
376 if (!sdev)
377 return NULL;
378
379 if (sdev->handler)
380 handler_name = kstrdup(sdev->handler->name, gfp);
381 put_device(&sdev->sdev_gendev);
382 return handler_name;
383}
384EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);
385