drivers/usb/usbip/stub_main.c

   1 /*
   2  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   3  *
   4  * This is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  17  * USA.
  18  */
  19
  20 #include <linux/string.h>
  21 #include <linux/module.h>
  22 #include <linux/device.h>
  23
  24 #include "usbip_common.h"
  25 #include "stub.h"
  26
  27 #define DRIVER_AUTHOR "Takahiro Hirofuchi"
  28 #define DRIVER_DESC "USB/IP Host Driver"
  29
  30 struct kmem_cache *stub_priv_cache;
  31
  32 /*
  33  * busid_tables defines matching busids that usbip can grab. A user can change
  34  * dynamically what device is locally used and what device is exported to a
  35  * remote host.
  36  */
  37 #define MAX_BUSID 16
  38 static struct bus_id_priv busid_table[MAX_BUSID];
  39 static spinlock_t busid_table_lock;
  40
  41 static void init_busid_table(void)
  42 {
  43         int i;
  44
  45         /*
  46          * This also sets the bus_table[i].status to
  47          * STUB_BUSID_OTHER, which is 0.
  48          */
  49         memset(busid_table, 0, sizeof(busid_table));
  50
  51         spin_lock_init(&busid_table_lock);
  52
  53         for (i = 0; i < MAX_BUSID; i++)
  54                 spin_lock_init(&busid_table[i].busid_lock);
  55 }
  56
  57 /*
  58  * Find the index of the busid by name.
  59  * Must be called with busid_table_lock held.
  60  */
  61 static int get_busid_idx(const char *busid)
  62 {
  63         int i;
  64         int idx = -1;
  65
  66         for (i = 0; i < MAX_BUSID; i++) {
  67                 spin_lock(&busid_table[i].busid_lock);
  68                 if (busid_table[i].name[0])
  69                         if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
  70                                 idx = i;
  71                                 spin_unlock(&busid_table[i].busid_lock);
  72                                 break;
  73                         }
  74                 spin_unlock(&busid_table[i].busid_lock);
  75         }
  76         return idx;
  77 }
  78
  79 /* Returns holding busid_lock. Should call put_busid_priv() to unlock */
  80 struct bus_id_priv *get_busid_priv(const char *busid)
  81 {
  82         int idx;
  83         struct bus_id_priv *bid = NULL;
  84
  85         spin_lock(&busid_table_lock);
  86         idx = get_busid_idx(busid);
  87         if (idx >= 0) {
  88                 bid = &(busid_table[idx]);
  89                 /* get busid_lock before returning */
  90                 spin_lock(&bid->busid_lock);
  91         }
  92         spin_unlock(&busid_table_lock);
  93
  94         return bid;
  95 }
  96
  97 void put_busid_priv(struct bus_id_priv *bid)
  98 {
  99         if (bid)
 100                 spin_unlock(&bid->busid_lock);
 101 }
 102
 103 static int add_match_busid(char *busid)
 104 {
 105         int i;
 106         int ret = -1;
 107
 108         spin_lock(&busid_table_lock);
 109         /* already registered? */
 110         if (get_busid_idx(busid) >= 0) {
 111                 ret = 0;
 112                 goto out;
 113         }
 114
 115         for (i = 0; i < MAX_BUSID; i++) {
 116                 spin_lock(&busid_table[i].busid_lock);
 117                 if (!busid_table[i].name[0]) {
 118                         strlcpy(busid_table[i].name, busid, BUSID_SIZE);
 119                         if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
 120                             (busid_table[i].status != STUB_BUSID_REMOV))
 121                                 busid_table[i].status = STUB_BUSID_ADDED;
 122                         ret = 0;
 123                         spin_unlock(&busid_table[i].busid_lock);
 124                         break;
 125                 }
 126                 spin_unlock(&busid_table[i].busid_lock);
 127         }
 128
 129 out:
 130         spin_unlock(&busid_table_lock);
 131
 132         return ret;
 133 }
 134
 135 int del_match_busid(char *busid)
 136 {
 137         int idx;
 138         int ret = -1;
 139
 140         spin_lock(&busid_table_lock);
 141         idx = get_busid_idx(busid);
 142         if (idx < 0)
 143                 goto out;
 144
 145         /* found */
 146         ret = 0;
 147
 148         spin_lock(&busid_table[idx].busid_lock);
 149
 150         if (busid_table[idx].status == STUB_BUSID_OTHER)
 151                 memset(busid_table[idx].name, 0, BUSID_SIZE);
 152
 153         if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
 154             (busid_table[idx].status != STUB_BUSID_ADDED))
 155                 busid_table[idx].status = STUB_BUSID_REMOV;
 156
 157         spin_unlock(&busid_table[idx].busid_lock);
 158 out:
 159         spin_unlock(&busid_table_lock);
 160
 161         return ret;
 162 }
 163
 164 static ssize_t show_match_busid(struct device_driver *drv, char *buf)
 165 {
 166         int i;
 167         char *out = buf;
 168
 169         spin_lock(&busid_table_lock);
 170         for (i = 0; i < MAX_BUSID; i++) {
 171                 spin_lock(&busid_table[i].busid_lock);
 172                 if (busid_table[i].name[0])
 173                         out += sprintf(out, "%s ", busid_table[i].name);
 174                 spin_unlock(&busid_table[i].busid_lock);
 175         }
 176         spin_unlock(&busid_table_lock);
 177         out += sprintf(out, "\n");
 178
 179         return out - buf;
 180 }
 181
 182 static ssize_t store_match_busid(struct device_driver *dev, const char *buf,
 183                                  size_t count)
 184 {
 185         int len;
 186         char busid[BUSID_SIZE];
 187
 188         if (count < 5)
 189                 return -EINVAL;
 190
 191         /* busid needs to include \0 termination */
 192         len = strlcpy(busid, buf + 4, BUSID_SIZE);
 193         if (sizeof(busid) <= len)
 194                 return -EINVAL;
 195
 196         if (!strncmp(buf, "add ", 4)) {
 197                 if (add_match_busid(busid) < 0)
 198                         return -ENOMEM;
 199
 200                 pr_debug("add busid %s\n", busid);
 201                 return count;
 202         }
 203
 204         if (!strncmp(buf, "del ", 4)) {
 205                 if (del_match_busid(busid) < 0)
 206                         return -ENODEV;
 207
 208                 pr_debug("del busid %s\n", busid);
 209                 return count;
 210         }
 211
 212         return -EINVAL;
 213 }
 214 static DRIVER_ATTR(match_busid, S_IRUSR | S_IWUSR, show_match_busid,
 215                    store_match_busid);
 216
 217 static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
 218 {
 219         int ret;
 220
 221         /* device_attach() callers should hold parent lock for USB */
 222         if (busid_priv->udev->dev.parent)
 223                 device_lock(busid_priv->udev->dev.parent);
 224         ret = device_attach(&busid_priv->udev->dev);
 225         if (busid_priv->udev->dev.parent)
 226                 device_unlock(busid_priv->udev->dev.parent);
 227         if (ret < 0) {
 228                 dev_err(&busid_priv->udev->dev, "rebind failed\n");
 229                 return ret;
 230         }
 231         return 0;
 232 }
 233
 234 static void stub_device_rebind(void)
 235 {
 236 #if IS_MODULE(CONFIG_USBIP_HOST)
 237         struct bus_id_priv *busid_priv;
 238         int i;
 239
 240         /* update status to STUB_BUSID_OTHER so probe ignores the device */
 241         spin_lock(&busid_table_lock);
 242         for (i = 0; i < MAX_BUSID; i++) {
 243                 if (busid_table[i].name[0] &&
 244                     busid_table[i].shutdown_busid) {
 245                         busid_priv = &(busid_table[i]);
 246                         busid_priv->status = STUB_BUSID_OTHER;
 247                 }
 248         }
 249         spin_unlock(&busid_table_lock);
 250
 251         /* now run rebind - no need to hold locks. driver files are removed */
 252         for (i = 0; i < MAX_BUSID; i++) {
 253                 if (busid_table[i].name[0] &&
 254                     busid_table[i].shutdown_busid) {
 255                         busid_priv = &(busid_table[i]);
 256                         do_rebind(busid_table[i].name, busid_priv);
 257                 }
 258         }
 259 #endif
 260 }
 261
 262 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 263                                  size_t count)
 264 {
 265         int ret;
 266         int len;
 267         struct bus_id_priv *bid;
 268
 269         /* buf length should be less that BUSID_SIZE */
 270         len = strnlen(buf, BUSID_SIZE);
 271
 272         if (!(len < BUSID_SIZE))
 273                 return -EINVAL;
 274
 275         bid = get_busid_priv(buf);
 276         if (!bid)
 277                 return -ENODEV;
 278
 279         /* mark the device for deletion so probe ignores it during rescan */
 280         bid->status = STUB_BUSID_OTHER;
 281         /* release the busid lock */
 282         put_busid_priv(bid);
 283
 284         ret = do_rebind((char *) buf, bid);
 285         if (ret < 0)
 286                 return ret;
 287
 288         /* delete device from busid_table */
 289         del_match_busid((char *) buf);
 290
 291         return count;
 292 }
 293
 294 static DRIVER_ATTR_WO(rebind);
 295
 296 static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
 297 {
 298         struct stub_priv *priv, *tmp;
 299
 300         list_for_each_entry_safe(priv, tmp, listhead, list) {
 301                 list_del(&priv->list);
 302                 return priv;
 303         }
 304
 305         return NULL;
 306 }
 307
 308 static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
 309 {
 310         unsigned long flags;
 311         struct stub_priv *priv;
 312
 313         spin_lock_irqsave(&sdev->priv_lock, flags);
 314
 315         priv = stub_priv_pop_from_listhead(&sdev->priv_init);
 316         if (priv)
 317                 goto done;
 318
 319         priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
 320         if (priv)
 321                 goto done;
 322
 323         priv = stub_priv_pop_from_listhead(&sdev->priv_free);
 324
 325 done:
 326         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 327
 328         return priv;
 329 }
 330
 331 void stub_device_cleanup_urbs(struct stub_device *sdev)
 332 {
 333         struct stub_priv *priv;
 334         struct urb *urb;
 335
 336         dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
 337
 338         while ((priv = stub_priv_pop(sdev))) {
 339                 urb = priv->urb;
 340                 dev_dbg(&sdev->udev->dev, "free urb seqnum %lu\n",
 341                         priv->seqnum);
 342                 usb_kill_urb(urb);
 343
 344                 kmem_cache_free(stub_priv_cache, priv);
 345
 346                 kfree(urb->transfer_buffer);
 347                 urb->transfer_buffer = NULL;
 348
 349                 kfree(urb->setup_packet);
 350                 urb->setup_packet = NULL;
 351
 352                 usb_free_urb(urb);
 353         }
 354 }
 355
 356 static int __init usbip_host_init(void)
 357 {
 358         int ret;
 359
 360         init_busid_table();
 361
 362         stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
 363         if (!stub_priv_cache) {
 364                 pr_err("kmem_cache_create failed\n");
 365                 return -ENOMEM;
 366         }
 367
 368         ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
 369         if (ret) {
 370                 pr_err("usb_register failed %d\n", ret);
 371                 goto err_usb_register;
 372         }
 373
 374         ret = driver_create_file(&stub_driver.drvwrap.driver,
 375                                  &driver_attr_match_busid);
 376         if (ret) {
 377                 pr_err("driver_create_file failed\n");
 378                 goto err_create_file;
 379         }
 380
 381         ret = driver_create_file(&stub_driver.drvwrap.driver,
 382                                  &driver_attr_rebind);
 383         if (ret) {
 384                 pr_err("driver_create_file failed\n");
 385                 goto err_create_file;
 386         }
 387
 388         pr_info(DRIVER_DESC " v" USBIP_VERSION "\n");
 389         return ret;
 390
 391 err_create_file:
 392         usb_deregister_device_driver(&stub_driver);
 393 err_usb_register:
 394         kmem_cache_destroy(stub_priv_cache);
 395         return ret;
 396 }
 397
 398 static void __exit usbip_host_exit(void)
 399 {
 400         driver_remove_file(&stub_driver.drvwrap.driver,
 401                            &driver_attr_match_busid);
 402
 403         driver_remove_file(&stub_driver.drvwrap.driver,
 404                            &driver_attr_rebind);
 405
 406         /*
 407          * deregister() calls stub_disconnect() for all devices. Device
 408          * specific data is cleared in stub_disconnect().
 409          */
 410         usb_deregister_device_driver(&stub_driver);
 411
 412         /* initiate scan to attach devices */
 413         stub_device_rebind();
 414
 415         kmem_cache_destroy(stub_priv_cache);
 416 }
 417
 418 module_init(usbip_host_init);
 419 module_exit(usbip_host_exit);
 420
 421 MODULE_AUTHOR(DRIVER_AUTHOR);
 422 MODULE_DESCRIPTION(DRIVER_DESC);
 423 MODULE_LICENSE("GPL");
 424 MODULE_VERSION(USBIP_VERSION);