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 match_busid_show(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 match_busid_store(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_RW(match_busid);
 215
 216 static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
 217 {
 218         int ret;
 219
 220         /* device_attach() callers should hold parent lock for USB */
 221         if (busid_priv->udev->dev.parent)
 222                 device_lock(busid_priv->udev->dev.parent);
 223         ret = device_attach(&busid_priv->udev->dev);
 224         if (busid_priv->udev->dev.parent)
 225                 device_unlock(busid_priv->udev->dev.parent);
 226         if (ret < 0) {
 227                 dev_err(&busid_priv->udev->dev, "rebind failed\n");
 228                 return ret;
 229         }
 230         return 0;
 231 }
 232
 233 static void stub_device_rebind(void)
 234 {
 235 #if IS_MODULE(CONFIG_USBIP_HOST)
 236         struct bus_id_priv *busid_priv;
 237         int i;
 238
 239         /* update status to STUB_BUSID_OTHER so probe ignores the device */
 240         spin_lock(&busid_table_lock);
 241         for (i = 0; i < MAX_BUSID; i++) {
 242                 if (busid_table[i].name[0] &&
 243                     busid_table[i].shutdown_busid) {
 244                         busid_priv = &(busid_table[i]);
 245                         busid_priv->status = STUB_BUSID_OTHER;
 246                 }
 247         }
 248         spin_unlock(&busid_table_lock);
 249
 250         /* now run rebind - no need to hold locks. driver files are removed */
 251         for (i = 0; i < MAX_BUSID; i++) {
 252                 if (busid_table[i].name[0] &&
 253                     busid_table[i].shutdown_busid) {
 254                         busid_priv = &(busid_table[i]);
 255                         do_rebind(busid_table[i].name, busid_priv);
 256                 }
 257         }
 258 #endif
 259 }
 260
 261 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
 262                                  size_t count)
 263 {
 264         int ret;
 265         int len;
 266         struct bus_id_priv *bid;
 267
 268         /* buf length should be less that BUSID_SIZE */
 269         len = strnlen(buf, BUSID_SIZE);
 270
 271         if (!(len < BUSID_SIZE))
 272                 return -EINVAL;
 273
 274         bid = get_busid_priv(buf);
 275         if (!bid)
 276                 return -ENODEV;
 277
 278         /* mark the device for deletion so probe ignores it during rescan */
 279         bid->status = STUB_BUSID_OTHER;
 280         /* release the busid lock */
 281         put_busid_priv(bid);
 282
 283         ret = do_rebind((char *) buf, bid);
 284         if (ret < 0)
 285                 return ret;
 286
 287         /* delete device from busid_table */
 288         del_match_busid((char *) buf);
 289
 290         return count;
 291 }
 292
 293 static DRIVER_ATTR_WO(rebind);
 294
 295 static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
 296 {
 297         struct stub_priv *priv, *tmp;
 298
 299         list_for_each_entry_safe(priv, tmp, listhead, list) {
 300                 list_del(&priv->list);
 301                 return priv;
 302         }
 303
 304         return NULL;
 305 }
 306
 307 static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
 308 {
 309         unsigned long flags;
 310         struct stub_priv *priv;
 311
 312         spin_lock_irqsave(&sdev->priv_lock, flags);
 313
 314         priv = stub_priv_pop_from_listhead(&sdev->priv_init);
 315         if (priv)
 316                 goto done;
 317
 318         priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
 319         if (priv)
 320                 goto done;
 321
 322         priv = stub_priv_pop_from_listhead(&sdev->priv_free);
 323
 324 done:
 325         spin_unlock_irqrestore(&sdev->priv_lock, flags);
 326
 327         return priv;
 328 }
 329
 330 void stub_device_cleanup_urbs(struct stub_device *sdev)
 331 {
 332         struct stub_priv *priv;
 333         struct urb *urb;
 334
 335         dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
 336
 337         while ((priv = stub_priv_pop(sdev))) {
 338                 urb = priv->urb;
 339                 dev_dbg(&sdev->udev->dev, "free urb seqnum %lu\n",
 340                         priv->seqnum);
 341                 usb_kill_urb(urb);
 342
 343                 kmem_cache_free(stub_priv_cache, priv);
 344
 345                 kfree(urb->transfer_buffer);
 346                 urb->transfer_buffer = NULL;
 347
 348                 kfree(urb->setup_packet);
 349                 urb->setup_packet = NULL;
 350
 351                 usb_free_urb(urb);
 352         }
 353 }
 354
 355 static int __init usbip_host_init(void)
 356 {
 357         int ret;
 358
 359         init_busid_table();
 360
 361         stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
 362         if (!stub_priv_cache) {
 363                 pr_err("kmem_cache_create failed\n");
 364                 return -ENOMEM;
 365         }
 366
 367         ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
 368         if (ret) {
 369                 pr_err("usb_register failed %d\n", ret);
 370                 goto err_usb_register;
 371         }
 372
 373         ret = driver_create_file(&stub_driver.drvwrap.driver,
 374                                  &driver_attr_match_busid);
 375         if (ret) {
 376                 pr_err("driver_create_file failed\n");
 377                 goto err_create_file;
 378         }
 379
 380         ret = driver_create_file(&stub_driver.drvwrap.driver,
 381                                  &driver_attr_rebind);
 382         if (ret) {
 383                 pr_err("driver_create_file failed\n");
 384                 goto err_create_file;
 385         }
 386
 387         return ret;
 388
 389 err_create_file:
 390         usb_deregister_device_driver(&stub_driver);
 391 err_usb_register:
 392         kmem_cache_destroy(stub_priv_cache);
 393         return ret;
 394 }
 395
 396 static void __exit usbip_host_exit(void)
 397 {
 398         driver_remove_file(&stub_driver.drvwrap.driver,
 399                            &driver_attr_match_busid);
 400
 401         driver_remove_file(&stub_driver.drvwrap.driver,
 402                            &driver_attr_rebind);
 403
 404         /*
 405          * deregister() calls stub_disconnect() for all devices. Device
 406          * specific data is cleared in stub_disconnect().
 407          */
 408         usb_deregister_device_driver(&stub_driver);
 409
 410         /* initiate scan to attach devices */
 411         stub_device_rebind();
 412
 413         kmem_cache_destroy(stub_priv_cache);
 414 }
 415
 416 module_init(usbip_host_init);
 417 module_exit(usbip_host_exit);
 418
 419 MODULE_AUTHOR(DRIVER_AUTHOR);
 420 MODULE_DESCRIPTION(DRIVER_DESC);
 421 MODULE_LICENSE("GPL");