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dd314058 DDG |
1 | /****************************************************************************** |
2 | * gntalloc.c | |
3 | * | |
4 | * Device for creating grant references (in user-space) that may be shared | |
5 | * with other domains. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this program; if not, write to the Free Software | |
14 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
15 | */ | |
16 | ||
17 | /* | |
18 | * This driver exists to allow userspace programs in Linux to allocate kernel | |
19 | * memory that will later be shared with another domain. Without this device, | |
20 | * Linux userspace programs cannot create grant references. | |
21 | * | |
22 | * How this stuff works: | |
23 | * X -> granting a page to Y | |
24 | * Y -> mapping the grant from X | |
25 | * | |
26 | * 1. X uses the gntalloc device to allocate a page of kernel memory, P. | |
27 | * 2. X creates an entry in the grant table that says domid(Y) can access P. | |
28 | * This is done without a hypercall unless the grant table needs expansion. | |
29 | * 3. X gives the grant reference identifier, GREF, to Y. | |
30 | * 4. Y maps the page, either directly into kernel memory for use in a backend | |
31 | * driver, or via a the gntdev device to map into the address space of an | |
32 | * application running in Y. This is the first point at which Xen does any | |
33 | * tracking of the page. | |
34 | * 5. A program in X mmap()s a segment of the gntalloc device that corresponds | |
35 | * to the shared page, and can now communicate with Y over the shared page. | |
36 | * | |
37 | * | |
38 | * NOTE TO USERSPACE LIBRARIES: | |
39 | * The grant allocation and mmap()ing are, naturally, two separate operations. | |
40 | * You set up the sharing by calling the create ioctl() and then the mmap(). | |
41 | * Teardown requires munmap() and either close() or ioctl(). | |
42 | * | |
43 | * WARNING: Since Xen does not allow a guest to forcibly end the use of a grant | |
44 | * reference, this device can be used to consume kernel memory by leaving grant | |
45 | * references mapped by another domain when an application exits. Therefore, | |
46 | * there is a global limit on the number of pages that can be allocated. When | |
47 | * all references to the page are unmapped, it will be freed during the next | |
48 | * grant operation. | |
49 | */ | |
50 | ||
51 | #include <linux/atomic.h> | |
52 | #include <linux/module.h> | |
53 | #include <linux/miscdevice.h> | |
54 | #include <linux/kernel.h> | |
55 | #include <linux/init.h> | |
56 | #include <linux/slab.h> | |
57 | #include <linux/fs.h> | |
58 | #include <linux/device.h> | |
59 | #include <linux/mm.h> | |
60 | #include <linux/uaccess.h> | |
61 | #include <linux/types.h> | |
62 | #include <linux/list.h> | |
bdc612dc | 63 | #include <linux/highmem.h> |
dd314058 DDG |
64 | |
65 | #include <xen/xen.h> | |
66 | #include <xen/page.h> | |
67 | #include <xen/grant_table.h> | |
68 | #include <xen/gntalloc.h> | |
bdc612dc | 69 | #include <xen/events.h> |
dd314058 DDG |
70 | |
71 | static int limit = 1024; | |
72 | module_param(limit, int, 0644); | |
73 | MODULE_PARM_DESC(limit, "Maximum number of grants that may be allocated by " | |
74 | "the gntalloc device"); | |
75 | ||
76 | static LIST_HEAD(gref_list); | |
8ca19a89 | 77 | static DEFINE_MUTEX(gref_mutex); |
dd314058 DDG |
78 | static int gref_size; |
79 | ||
bdc612dc DDG |
80 | struct notify_info { |
81 | uint16_t pgoff:12; /* Bits 0-11: Offset of the byte to clear */ | |
82 | uint16_t flags:2; /* Bits 12-13: Unmap notification flags */ | |
83 | int event; /* Port (event channel) to notify */ | |
84 | }; | |
85 | ||
dd314058 DDG |
86 | /* Metadata on a grant reference. */ |
87 | struct gntalloc_gref { | |
88 | struct list_head next_gref; /* list entry gref_list */ | |
89 | struct list_head next_file; /* list entry file->list, if open */ | |
90 | struct page *page; /* The shared page */ | |
91 | uint64_t file_index; /* File offset for mmap() */ | |
92 | unsigned int users; /* Use count - when zero, waiting on Xen */ | |
93 | grant_ref_t gref_id; /* The grant reference number */ | |
bdc612dc | 94 | struct notify_info notify; /* Unmap notification */ |
dd314058 DDG |
95 | }; |
96 | ||
97 | struct gntalloc_file_private_data { | |
98 | struct list_head list; | |
99 | uint64_t index; | |
100 | }; | |
101 | ||
102 | static void __del_gref(struct gntalloc_gref *gref); | |
103 | ||
104 | static void do_cleanup(void) | |
105 | { | |
106 | struct gntalloc_gref *gref, *n; | |
107 | list_for_each_entry_safe(gref, n, &gref_list, next_gref) { | |
108 | if (!gref->users) | |
109 | __del_gref(gref); | |
110 | } | |
111 | } | |
112 | ||
113 | static int add_grefs(struct ioctl_gntalloc_alloc_gref *op, | |
114 | uint32_t *gref_ids, struct gntalloc_file_private_data *priv) | |
115 | { | |
116 | int i, rc, readonly; | |
117 | LIST_HEAD(queue_gref); | |
118 | LIST_HEAD(queue_file); | |
119 | struct gntalloc_gref *gref; | |
120 | ||
121 | readonly = !(op->flags & GNTALLOC_FLAG_WRITABLE); | |
122 | rc = -ENOMEM; | |
123 | for (i = 0; i < op->count; i++) { | |
124 | gref = kzalloc(sizeof(*gref), GFP_KERNEL); | |
125 | if (!gref) | |
126 | goto undo; | |
127 | list_add_tail(&gref->next_gref, &queue_gref); | |
128 | list_add_tail(&gref->next_file, &queue_file); | |
129 | gref->users = 1; | |
130 | gref->file_index = op->index + i * PAGE_SIZE; | |
131 | gref->page = alloc_page(GFP_KERNEL|__GFP_ZERO); | |
132 | if (!gref->page) | |
133 | goto undo; | |
134 | ||
135 | /* Grant foreign access to the page. */ | |
136 | gref->gref_id = gnttab_grant_foreign_access(op->domid, | |
137 | pfn_to_mfn(page_to_pfn(gref->page)), readonly); | |
138 | if (gref->gref_id < 0) { | |
139 | rc = gref->gref_id; | |
140 | goto undo; | |
141 | } | |
142 | gref_ids[i] = gref->gref_id; | |
143 | } | |
144 | ||
145 | /* Add to gref lists. */ | |
8ca19a89 | 146 | mutex_lock(&gref_mutex); |
dd314058 DDG |
147 | list_splice_tail(&queue_gref, &gref_list); |
148 | list_splice_tail(&queue_file, &priv->list); | |
8ca19a89 | 149 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
150 | |
151 | return 0; | |
152 | ||
153 | undo: | |
8ca19a89 | 154 | mutex_lock(&gref_mutex); |
dd314058 DDG |
155 | gref_size -= (op->count - i); |
156 | ||
157 | list_for_each_entry(gref, &queue_file, next_file) { | |
158 | /* __del_gref does not remove from queue_file */ | |
159 | __del_gref(gref); | |
160 | } | |
161 | ||
162 | /* It's possible for the target domain to map the just-allocated grant | |
163 | * references by blindly guessing their IDs; if this is done, then | |
164 | * __del_gref will leave them in the queue_gref list. They need to be | |
165 | * added to the global list so that we can free them when they are no | |
166 | * longer referenced. | |
167 | */ | |
168 | if (unlikely(!list_empty(&queue_gref))) | |
169 | list_splice_tail(&queue_gref, &gref_list); | |
8ca19a89 | 170 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
171 | return rc; |
172 | } | |
173 | ||
174 | static void __del_gref(struct gntalloc_gref *gref) | |
175 | { | |
bdc612dc DDG |
176 | if (gref->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { |
177 | uint8_t *tmp = kmap(gref->page); | |
178 | tmp[gref->notify.pgoff] = 0; | |
179 | kunmap(gref->page); | |
180 | } | |
0cc678f8 | 181 | if (gref->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { |
bdc612dc | 182 | notify_remote_via_evtchn(gref->notify.event); |
0cc678f8 DDG |
183 | evtchn_put(gref->notify.event); |
184 | } | |
bdc612dc DDG |
185 | |
186 | gref->notify.flags = 0; | |
187 | ||
dd314058 DDG |
188 | if (gref->gref_id > 0) { |
189 | if (gnttab_query_foreign_access(gref->gref_id)) | |
190 | return; | |
191 | ||
192 | if (!gnttab_end_foreign_access_ref(gref->gref_id, 0)) | |
193 | return; | |
194 | } | |
195 | ||
196 | gref_size--; | |
197 | list_del(&gref->next_gref); | |
198 | ||
199 | if (gref->page) | |
200 | __free_page(gref->page); | |
201 | ||
202 | kfree(gref); | |
203 | } | |
204 | ||
205 | /* finds contiguous grant references in a file, returns the first */ | |
206 | static struct gntalloc_gref *find_grefs(struct gntalloc_file_private_data *priv, | |
207 | uint64_t index, uint32_t count) | |
208 | { | |
209 | struct gntalloc_gref *rv = NULL, *gref; | |
210 | list_for_each_entry(gref, &priv->list, next_file) { | |
211 | if (gref->file_index == index && !rv) | |
212 | rv = gref; | |
213 | if (rv) { | |
214 | if (gref->file_index != index) | |
215 | return NULL; | |
216 | index += PAGE_SIZE; | |
217 | count--; | |
218 | if (count == 0) | |
219 | return rv; | |
220 | } | |
221 | } | |
222 | return NULL; | |
223 | } | |
224 | ||
225 | /* | |
226 | * ------------------------------------- | |
227 | * File operations. | |
228 | * ------------------------------------- | |
229 | */ | |
230 | static int gntalloc_open(struct inode *inode, struct file *filp) | |
231 | { | |
232 | struct gntalloc_file_private_data *priv; | |
233 | ||
234 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
235 | if (!priv) | |
236 | goto out_nomem; | |
237 | INIT_LIST_HEAD(&priv->list); | |
238 | ||
239 | filp->private_data = priv; | |
240 | ||
241 | pr_debug("%s: priv %p\n", __func__, priv); | |
242 | ||
243 | return 0; | |
244 | ||
245 | out_nomem: | |
246 | return -ENOMEM; | |
247 | } | |
248 | ||
249 | static int gntalloc_release(struct inode *inode, struct file *filp) | |
250 | { | |
251 | struct gntalloc_file_private_data *priv = filp->private_data; | |
252 | struct gntalloc_gref *gref; | |
253 | ||
254 | pr_debug("%s: priv %p\n", __func__, priv); | |
255 | ||
8ca19a89 | 256 | mutex_lock(&gref_mutex); |
dd314058 DDG |
257 | while (!list_empty(&priv->list)) { |
258 | gref = list_entry(priv->list.next, | |
259 | struct gntalloc_gref, next_file); | |
260 | list_del(&gref->next_file); | |
261 | gref->users--; | |
262 | if (gref->users == 0) | |
263 | __del_gref(gref); | |
264 | } | |
265 | kfree(priv); | |
8ca19a89 | 266 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
267 | |
268 | return 0; | |
269 | } | |
270 | ||
271 | static long gntalloc_ioctl_alloc(struct gntalloc_file_private_data *priv, | |
272 | struct ioctl_gntalloc_alloc_gref __user *arg) | |
273 | { | |
274 | int rc = 0; | |
275 | struct ioctl_gntalloc_alloc_gref op; | |
276 | uint32_t *gref_ids; | |
277 | ||
278 | pr_debug("%s: priv %p\n", __func__, priv); | |
279 | ||
280 | if (copy_from_user(&op, arg, sizeof(op))) { | |
281 | rc = -EFAULT; | |
282 | goto out; | |
283 | } | |
284 | ||
285 | gref_ids = kzalloc(sizeof(gref_ids[0]) * op.count, GFP_TEMPORARY); | |
286 | if (!gref_ids) { | |
287 | rc = -ENOMEM; | |
288 | goto out; | |
289 | } | |
290 | ||
8ca19a89 | 291 | mutex_lock(&gref_mutex); |
dd314058 DDG |
292 | /* Clean up pages that were at zero (local) users but were still mapped |
293 | * by remote domains. Since those pages count towards the limit that we | |
294 | * are about to enforce, removing them here is a good idea. | |
295 | */ | |
296 | do_cleanup(); | |
297 | if (gref_size + op.count > limit) { | |
8ca19a89 | 298 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
299 | rc = -ENOSPC; |
300 | goto out_free; | |
301 | } | |
302 | gref_size += op.count; | |
303 | op.index = priv->index; | |
304 | priv->index += op.count * PAGE_SIZE; | |
8ca19a89 | 305 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
306 | |
307 | rc = add_grefs(&op, gref_ids, priv); | |
308 | if (rc < 0) | |
309 | goto out_free; | |
310 | ||
311 | /* Once we finish add_grefs, it is unsafe to touch the new reference, | |
312 | * since it is possible for a concurrent ioctl to remove it (by guessing | |
313 | * its index). If the userspace application doesn't provide valid memory | |
314 | * to write the IDs to, then it will need to close the file in order to | |
315 | * release - which it will do by segfaulting when it tries to access the | |
316 | * IDs to close them. | |
317 | */ | |
318 | if (copy_to_user(arg, &op, sizeof(op))) { | |
319 | rc = -EFAULT; | |
320 | goto out_free; | |
321 | } | |
322 | if (copy_to_user(arg->gref_ids, gref_ids, | |
323 | sizeof(gref_ids[0]) * op.count)) { | |
324 | rc = -EFAULT; | |
325 | goto out_free; | |
326 | } | |
327 | ||
328 | out_free: | |
329 | kfree(gref_ids); | |
330 | out: | |
331 | return rc; | |
332 | } | |
333 | ||
334 | static long gntalloc_ioctl_dealloc(struct gntalloc_file_private_data *priv, | |
335 | void __user *arg) | |
336 | { | |
337 | int i, rc = 0; | |
338 | struct ioctl_gntalloc_dealloc_gref op; | |
339 | struct gntalloc_gref *gref, *n; | |
340 | ||
341 | pr_debug("%s: priv %p\n", __func__, priv); | |
342 | ||
343 | if (copy_from_user(&op, arg, sizeof(op))) { | |
344 | rc = -EFAULT; | |
345 | goto dealloc_grant_out; | |
346 | } | |
347 | ||
8ca19a89 | 348 | mutex_lock(&gref_mutex); |
dd314058 DDG |
349 | gref = find_grefs(priv, op.index, op.count); |
350 | if (gref) { | |
351 | /* Remove from the file list only, and decrease reference count. | |
352 | * The later call to do_cleanup() will remove from gref_list and | |
353 | * free the memory if the pages aren't mapped anywhere. | |
354 | */ | |
355 | for (i = 0; i < op.count; i++) { | |
356 | n = list_entry(gref->next_file.next, | |
357 | struct gntalloc_gref, next_file); | |
358 | list_del(&gref->next_file); | |
359 | gref->users--; | |
360 | gref = n; | |
361 | } | |
362 | } else { | |
363 | rc = -EINVAL; | |
364 | } | |
365 | ||
366 | do_cleanup(); | |
367 | ||
8ca19a89 | 368 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
369 | dealloc_grant_out: |
370 | return rc; | |
371 | } | |
372 | ||
bdc612dc DDG |
373 | static long gntalloc_ioctl_unmap_notify(struct gntalloc_file_private_data *priv, |
374 | void __user *arg) | |
375 | { | |
376 | struct ioctl_gntalloc_unmap_notify op; | |
377 | struct gntalloc_gref *gref; | |
378 | uint64_t index; | |
379 | int pgoff; | |
380 | int rc; | |
381 | ||
382 | if (copy_from_user(&op, arg, sizeof(op))) | |
383 | return -EFAULT; | |
384 | ||
385 | index = op.index & ~(PAGE_SIZE - 1); | |
386 | pgoff = op.index & (PAGE_SIZE - 1); | |
387 | ||
8ca19a89 | 388 | mutex_lock(&gref_mutex); |
bdc612dc DDG |
389 | |
390 | gref = find_grefs(priv, index, 1); | |
391 | if (!gref) { | |
392 | rc = -ENOENT; | |
393 | goto unlock_out; | |
394 | } | |
395 | ||
396 | if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) { | |
397 | rc = -EINVAL; | |
398 | goto unlock_out; | |
399 | } | |
400 | ||
0cc678f8 DDG |
401 | /* We need to grab a reference to the event channel we are going to use |
402 | * to send the notify before releasing the reference we may already have | |
403 | * (if someone has called this ioctl twice). This is required so that | |
404 | * it is possible to change the clear_byte part of the notification | |
405 | * without disturbing the event channel part, which may now be the last | |
406 | * reference to that event channel. | |
407 | */ | |
408 | if (op.action & UNMAP_NOTIFY_SEND_EVENT) { | |
409 | if (evtchn_get(op.event_channel_port)) { | |
410 | rc = -EINVAL; | |
411 | goto unlock_out; | |
412 | } | |
413 | } | |
414 | ||
415 | if (gref->notify.flags & UNMAP_NOTIFY_SEND_EVENT) | |
416 | evtchn_put(gref->notify.event); | |
417 | ||
bdc612dc DDG |
418 | gref->notify.flags = op.action; |
419 | gref->notify.pgoff = pgoff; | |
420 | gref->notify.event = op.event_channel_port; | |
421 | rc = 0; | |
8ca19a89 | 422 | |
bdc612dc | 423 | unlock_out: |
8ca19a89 | 424 | mutex_unlock(&gref_mutex); |
bdc612dc DDG |
425 | return rc; |
426 | } | |
427 | ||
dd314058 DDG |
428 | static long gntalloc_ioctl(struct file *filp, unsigned int cmd, |
429 | unsigned long arg) | |
430 | { | |
431 | struct gntalloc_file_private_data *priv = filp->private_data; | |
432 | ||
433 | switch (cmd) { | |
434 | case IOCTL_GNTALLOC_ALLOC_GREF: | |
435 | return gntalloc_ioctl_alloc(priv, (void __user *)arg); | |
436 | ||
437 | case IOCTL_GNTALLOC_DEALLOC_GREF: | |
438 | return gntalloc_ioctl_dealloc(priv, (void __user *)arg); | |
439 | ||
bdc612dc DDG |
440 | case IOCTL_GNTALLOC_SET_UNMAP_NOTIFY: |
441 | return gntalloc_ioctl_unmap_notify(priv, (void __user *)arg); | |
442 | ||
dd314058 DDG |
443 | default: |
444 | return -ENOIOCTLCMD; | |
445 | } | |
446 | ||
447 | return 0; | |
448 | } | |
449 | ||
d79647ae DDG |
450 | static void gntalloc_vma_open(struct vm_area_struct *vma) |
451 | { | |
452 | struct gntalloc_gref *gref = vma->vm_private_data; | |
453 | if (!gref) | |
454 | return; | |
455 | ||
8ca19a89 | 456 | mutex_lock(&gref_mutex); |
d79647ae | 457 | gref->users++; |
8ca19a89 | 458 | mutex_unlock(&gref_mutex); |
d79647ae DDG |
459 | } |
460 | ||
dd314058 DDG |
461 | static void gntalloc_vma_close(struct vm_area_struct *vma) |
462 | { | |
463 | struct gntalloc_gref *gref = vma->vm_private_data; | |
464 | if (!gref) | |
465 | return; | |
466 | ||
8ca19a89 | 467 | mutex_lock(&gref_mutex); |
dd314058 DDG |
468 | gref->users--; |
469 | if (gref->users == 0) | |
470 | __del_gref(gref); | |
8ca19a89 | 471 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
472 | } |
473 | ||
474 | static struct vm_operations_struct gntalloc_vmops = { | |
d79647ae | 475 | .open = gntalloc_vma_open, |
dd314058 DDG |
476 | .close = gntalloc_vma_close, |
477 | }; | |
478 | ||
479 | static int gntalloc_mmap(struct file *filp, struct vm_area_struct *vma) | |
480 | { | |
481 | struct gntalloc_file_private_data *priv = filp->private_data; | |
482 | struct gntalloc_gref *gref; | |
483 | int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
484 | int rv, i; | |
485 | ||
486 | pr_debug("%s: priv %p, page %lu+%d\n", __func__, | |
487 | priv, vma->vm_pgoff, count); | |
488 | ||
489 | if (!(vma->vm_flags & VM_SHARED)) { | |
490 | printk(KERN_ERR "%s: Mapping must be shared.\n", __func__); | |
491 | return -EINVAL; | |
492 | } | |
493 | ||
8ca19a89 | 494 | mutex_lock(&gref_mutex); |
dd314058 DDG |
495 | gref = find_grefs(priv, vma->vm_pgoff << PAGE_SHIFT, count); |
496 | if (gref == NULL) { | |
497 | rv = -ENOENT; | |
498 | pr_debug("%s: Could not find grant reference", | |
499 | __func__); | |
500 | goto out_unlock; | |
501 | } | |
502 | ||
503 | vma->vm_private_data = gref; | |
504 | ||
505 | vma->vm_flags |= VM_RESERVED; | |
dd314058 DDG |
506 | |
507 | vma->vm_ops = &gntalloc_vmops; | |
508 | ||
509 | for (i = 0; i < count; i++) { | |
510 | gref->users++; | |
511 | rv = vm_insert_page(vma, vma->vm_start + i * PAGE_SIZE, | |
512 | gref->page); | |
513 | if (rv) | |
514 | goto out_unlock; | |
515 | ||
516 | gref = list_entry(gref->next_file.next, | |
517 | struct gntalloc_gref, next_file); | |
518 | } | |
519 | rv = 0; | |
520 | ||
521 | out_unlock: | |
8ca19a89 | 522 | mutex_unlock(&gref_mutex); |
dd314058 DDG |
523 | return rv; |
524 | } | |
525 | ||
526 | static const struct file_operations gntalloc_fops = { | |
527 | .owner = THIS_MODULE, | |
528 | .open = gntalloc_open, | |
529 | .release = gntalloc_release, | |
530 | .unlocked_ioctl = gntalloc_ioctl, | |
531 | .mmap = gntalloc_mmap | |
532 | }; | |
533 | ||
534 | /* | |
535 | * ------------------------------------- | |
536 | * Module creation/destruction. | |
537 | * ------------------------------------- | |
538 | */ | |
539 | static struct miscdevice gntalloc_miscdev = { | |
540 | .minor = MISC_DYNAMIC_MINOR, | |
541 | .name = "xen/gntalloc", | |
542 | .fops = &gntalloc_fops, | |
543 | }; | |
544 | ||
545 | static int __init gntalloc_init(void) | |
546 | { | |
547 | int err; | |
548 | ||
549 | if (!xen_domain()) | |
550 | return -ENODEV; | |
551 | ||
552 | err = misc_register(&gntalloc_miscdev); | |
553 | if (err != 0) { | |
554 | printk(KERN_ERR "Could not register misc gntalloc device\n"); | |
555 | return err; | |
556 | } | |
557 | ||
558 | pr_debug("Created grant allocation device at %d,%d\n", | |
559 | MISC_MAJOR, gntalloc_miscdev.minor); | |
560 | ||
561 | return 0; | |
562 | } | |
563 | ||
564 | static void __exit gntalloc_exit(void) | |
565 | { | |
566 | misc_deregister(&gntalloc_miscdev); | |
567 | } | |
568 | ||
569 | module_init(gntalloc_init); | |
570 | module_exit(gntalloc_exit); | |
571 | ||
572 | MODULE_LICENSE("GPL"); | |
573 | MODULE_AUTHOR("Carter Weatherly <carter.weatherly@jhuapl.edu>, " | |
574 | "Daniel De Graaf <dgdegra@tycho.nsa.gov>"); | |
575 | MODULE_DESCRIPTION("User-space grant reference allocator driver"); |