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xen/gntdev: Fix sleep-inside-spinlock
[linux-btrfs-devel.git] / drivers / xen / gntdev.c
blob880798aae2f2ae868bc9cc3206517901c1560afa
1 /******************************************************************************
2 * gntdev.c
3 *
4 * Device for accessing (in user-space) pages that have been granted by other
5 * domains.
6 *
7 * Copyright (c) 2006-2007, D G Murray.
8 * (c) 2009 Gerd Hoffmann <kraxel@redhat.com>
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20 #undef DEBUG
21
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/miscdevice.h>
26 #include <linux/fs.h>
27 #include <linux/mm.h>
28 #include <linux/mman.h>
29 #include <linux/mmu_notifier.h>
30 #include <linux/types.h>
31 #include <linux/uaccess.h>
32 #include <linux/sched.h>
33 #include <linux/spinlock.h>
34 #include <linux/slab.h>
35 #include <linux/highmem.h>
36
37 #include <xen/xen.h>
38 #include <xen/grant_table.h>
39 #include <xen/balloon.h>
40 #include <xen/gntdev.h>
41 #include <xen/events.h>
42 #include <asm/xen/hypervisor.h>
43 #include <asm/xen/hypercall.h>
44 #include <asm/xen/page.h>
45
46 MODULE_LICENSE("GPL");
47 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
48 "Gerd Hoffmann <kraxel@redhat.com>");
49 MODULE_DESCRIPTION("User-space granted page access driver");
50
51 static int limit = 1024*1024;
52 module_param(limit, int, 0644);
53 MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by "
54 "the gntdev device");
55
56 static atomic_t pages_mapped = ATOMIC_INIT(0);
57
58 static int use_ptemod;
59
60 struct gntdev_priv {
61 struct list_head maps;
62 /* lock protects maps from concurrent changes */
63 spinlock_t lock;
64 struct mm_struct *mm;
65 struct mmu_notifier mn;
66 };
67
68 struct unmap_notify {
69 int flags;
70 /* Address relative to the start of the grant_map */
71 int addr;
72 int event;
73 };
74
75 struct grant_map {
76 struct list_head next;
77 struct vm_area_struct *vma;
78 int index;
79 int count;
80 int flags;
81 atomic_t users;
82 struct unmap_notify notify;
83 struct ioctl_gntdev_grant_ref *grants;
84 struct gnttab_map_grant_ref *map_ops;
85 struct gnttab_unmap_grant_ref *unmap_ops;
86 struct gnttab_map_grant_ref *kmap_ops;
87 struct page **pages;
88 };
89
90 static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
91
92 /* ------------------------------------------------------------------ */
93
94 static void gntdev_print_maps(struct gntdev_priv *priv,
95 char *text, int text_index)
96 {
97 #ifdef DEBUG
98 struct grant_map *map;
99
100 pr_debug("%s: maps list (priv %p)\n", __func__, priv);
101 list_for_each_entry(map, &priv->maps, next)
102 pr_debug(" index %2d, count %2d %s\n",
103 map->index, map->count,
104 map->index == text_index && text ? text : "");
105 #endif
106 }
107
108 static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
109 {
110 struct grant_map *add;
111 int i;
112
113 add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
114 if (NULL == add)
115 return NULL;
116
117 add->grants = kzalloc(sizeof(add->grants[0]) * count, GFP_KERNEL);
118 add->map_ops = kzalloc(sizeof(add->map_ops[0]) * count, GFP_KERNEL);
119 add->unmap_ops = kzalloc(sizeof(add->unmap_ops[0]) * count, GFP_KERNEL);
120 add->kmap_ops = kzalloc(sizeof(add->kmap_ops[0]) * count, GFP_KERNEL);
121 add->pages = kzalloc(sizeof(add->pages[0]) * count, GFP_KERNEL);
122 if (NULL == add->grants ||
123 NULL == add->map_ops ||
124 NULL == add->unmap_ops ||
125 NULL == add->kmap_ops ||
126 NULL == add->pages)
127 goto err;
128
129 if (alloc_xenballooned_pages(count, add->pages, false /* lowmem */))
130 goto err;
131
132 for (i = 0; i < count; i++) {
133 add->map_ops[i].handle = -1;
134 add->unmap_ops[i].handle = -1;
135 add->kmap_ops[i].handle = -1;
136 }
137
138 add->index = 0;
139 add->count = count;
140 atomic_set(&add->users, 1);
141
142 return add;
143
144 err:
145 kfree(add->pages);
146 kfree(add->grants);
147 kfree(add->map_ops);
148 kfree(add->unmap_ops);
149 kfree(add->kmap_ops);
150 kfree(add);
151 return NULL;
152 }
153
154 static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
155 {
156 struct grant_map *map;
157
158 list_for_each_entry(map, &priv->maps, next) {
159 if (add->index + add->count < map->index) {
160 list_add_tail(&add->next, &map->next);
161 goto done;
162 }
163 add->index = map->index + map->count;
164 }
165 list_add_tail(&add->next, &priv->maps);
166
167 done:
168 gntdev_print_maps(priv, "[new]", add->index);
169 }
170
171 static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
172 int index, int count)
173 {
174 struct grant_map *map;
175
176 list_for_each_entry(map, &priv->maps, next) {
177 if (map->index != index)
178 continue;
179 if (count && map->count != count)
180 continue;
181 return map;
182 }
183 return NULL;
184 }
185
186 static void gntdev_put_map(struct grant_map *map)
187 {
188 if (!map)
189 return;
190
191 if (!atomic_dec_and_test(&map->users))
192 return;
193
194 atomic_sub(map->count, &pages_mapped);
195
196 if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
197 notify_remote_via_evtchn(map->notify.event);
198 }
199
200 if (map->pages) {
201 if (!use_ptemod)
202 unmap_grant_pages(map, 0, map->count);
203
204 free_xenballooned_pages(map->count, map->pages);
205 }
206 kfree(map->pages);
207 kfree(map->grants);
208 kfree(map->map_ops);
209 kfree(map->unmap_ops);
210 kfree(map);
211 }
212
213 /* ------------------------------------------------------------------ */
214
215 static int find_grant_ptes(pte_t *pte, pgtable_t token,
216 unsigned long addr, void *data)
217 {
218 struct grant_map *map = data;
219 unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
220 int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
221 u64 pte_maddr;
222
223 BUG_ON(pgnr >= map->count);
224 pte_maddr = arbitrary_virt_to_machine(pte).maddr;
225
226 gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
227 map->grants[pgnr].ref,
228 map->grants[pgnr].domid);
229 gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
230 -1 /* handle */);
231 return 0;
232 }
233
234 static int map_grant_pages(struct grant_map *map)
235 {
236 int i, err = 0;
237
238 if (!use_ptemod) {
239 /* Note: it could already be mapped */
240 if (map->map_ops[0].handle != -1)
241 return 0;
242 for (i = 0; i < map->count; i++) {
243 unsigned long addr = (unsigned long)
244 pfn_to_kaddr(page_to_pfn(map->pages[i]));
245 gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
246 map->grants[i].ref,
247 map->grants[i].domid);
248 gnttab_set_unmap_op(&map->unmap_ops[i], addr,
249 map->flags, -1 /* handle */);
250 }
251 } else {
252 /*
253 * Setup the map_ops corresponding to the pte entries pointing
254 * to the kernel linear addresses of the struct pages.
255 * These ptes are completely different from the user ptes dealt
256 * with find_grant_ptes.
257 */
258 for (i = 0; i < map->count; i++) {
259 unsigned level;
260 unsigned long address = (unsigned long)
261 pfn_to_kaddr(page_to_pfn(map->pages[i]));
262 pte_t *ptep;
263 u64 pte_maddr = 0;
264 BUG_ON(PageHighMem(map->pages[i]));
265
266 ptep = lookup_address(address, &level);
267 pte_maddr = arbitrary_virt_to_machine(ptep).maddr;
268 gnttab_set_map_op(&map->kmap_ops[i], pte_maddr,
269 map->flags |
270 GNTMAP_host_map |
271 GNTMAP_contains_pte,
272 map->grants[i].ref,
273 map->grants[i].domid);
274 }
275 }
276
277 pr_debug("map %d+%d\n", map->index, map->count);
278 err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
279 map->pages, map->count);
280 if (err)
281 return err;
282
283 for (i = 0; i < map->count; i++) {
284 if (map->map_ops[i].status)
285 err = -EINVAL;
286 else {
287 BUG_ON(map->map_ops[i].handle == -1);
288 map->unmap_ops[i].handle = map->map_ops[i].handle;
289 pr_debug("map handle=%d\n", map->map_ops[i].handle);
290 }
291 }
292 return err;
293 }
294
295 static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
296 {
297 int i, err = 0;
298
299 if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
300 int pgno = (map->notify.addr >> PAGE_SHIFT);
301 if (pgno >= offset && pgno < offset + pages && use_ptemod) {
302 void __user *tmp = (void __user *)
303 map->vma->vm_start + map->notify.addr;
304 err = copy_to_user(tmp, &err, 1);
305 if (err)
306 return -EFAULT;
307 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
308 } else if (pgno >= offset && pgno < offset + pages) {
309 uint8_t *tmp = kmap(map->pages[pgno]);
310 tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
311 kunmap(map->pages[pgno]);
312 map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
313 }
314 }
315
316 err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages + offset, pages);
317 if (err)
318 return err;
319
320 for (i = 0; i < pages; i++) {
321 if (map->unmap_ops[offset+i].status)
322 err = -EINVAL;
323 pr_debug("unmap handle=%d st=%d\n",
324 map->unmap_ops[offset+i].handle,
325 map->unmap_ops[offset+i].status);
326 map->unmap_ops[offset+i].handle = -1;
327 }
328 return err;
329 }
330
331 static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
332 {
333 int range, err = 0;
334
335 pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
336
337 /* It is possible the requested range will have a "hole" where we
338 * already unmapped some of the grants. Only unmap valid ranges.
339 */
340 while (pages && !err) {
341 while (pages && map->unmap_ops[offset].handle == -1) {
342 offset++;
343 pages--;
344 }
345 range = 0;
346 while (range < pages) {
347 if (map->unmap_ops[offset+range].handle == -1) {
348 range--;
349 break;
350 }
351 range++;
352 }
353 err = __unmap_grant_pages(map, offset, range);
354 offset += range;
355 pages -= range;
356 }
357
358 return err;
359 }
360
361 /* ------------------------------------------------------------------ */
362
363 static void gntdev_vma_open(struct vm_area_struct *vma)
364 {
365 struct grant_map *map = vma->vm_private_data;
366
367 pr_debug("gntdev_vma_open %p\n", vma);
368 atomic_inc(&map->users);
369 }
370
371 static void gntdev_vma_close(struct vm_area_struct *vma)
372 {
373 struct grant_map *map = vma->vm_private_data;
374
375 pr_debug("gntdev_vma_close %p\n", vma);
376 map->vma = NULL;
377 vma->vm_private_data = NULL;
378 gntdev_put_map(map);
379 }
380
381 static struct vm_operations_struct gntdev_vmops = {
382 .open = gntdev_vma_open,
383 .close = gntdev_vma_close,
384 };
385
386 /* ------------------------------------------------------------------ */
387
388 static void mn_invl_range_start(struct mmu_notifier *mn,
389 struct mm_struct *mm,
390 unsigned long start, unsigned long end)
391 {
392 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
393 struct grant_map *map;
394 unsigned long mstart, mend;
395 int err;
396
397 spin_lock(&priv->lock);
398 list_for_each_entry(map, &priv->maps, next) {
399 if (!map->vma)
400 continue;
401 if (map->vma->vm_start >= end)
402 continue;
403 if (map->vma->vm_end <= start)
404 continue;
405 mstart = max(start, map->vma->vm_start);
406 mend = min(end, map->vma->vm_end);
407 pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
408 map->index, map->count,
409 map->vma->vm_start, map->vma->vm_end,
410 start, end, mstart, mend);
411 err = unmap_grant_pages(map,
412 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
413 (mend - mstart) >> PAGE_SHIFT);
414 WARN_ON(err);
415 }
416 spin_unlock(&priv->lock);
417 }
418
419 static void mn_invl_page(struct mmu_notifier *mn,
420 struct mm_struct *mm,
421 unsigned long address)
422 {
423 mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
424 }
425
426 static void mn_release(struct mmu_notifier *mn,
427 struct mm_struct *mm)
428 {
429 struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
430 struct grant_map *map;
431 int err;
432
433 spin_lock(&priv->lock);
434 list_for_each_entry(map, &priv->maps, next) {
435 if (!map->vma)
436 continue;
437 pr_debug("map %d+%d (%lx %lx)\n",
438 map->index, map->count,
439 map->vma->vm_start, map->vma->vm_end);
440 err = unmap_grant_pages(map, /* offset */ 0, map->count);
441 WARN_ON(err);
442 }
443 spin_unlock(&priv->lock);
444 }
445
446 struct mmu_notifier_ops gntdev_mmu_ops = {
447 .release = mn_release,
448 .invalidate_page = mn_invl_page,
449 .invalidate_range_start = mn_invl_range_start,
450 };
451
452 /* ------------------------------------------------------------------ */
453
454 static int gntdev_open(struct inode *inode, struct file *flip)
455 {
456 struct gntdev_priv *priv;
457 int ret = 0;
458
459 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
460 if (!priv)
461 return -ENOMEM;
462
463 INIT_LIST_HEAD(&priv->maps);
464 spin_lock_init(&priv->lock);
465
466 if (use_ptemod) {
467 priv->mm = get_task_mm(current);
468 if (!priv->mm) {
469 kfree(priv);
470 return -ENOMEM;
471 }
472 priv->mn.ops = &gntdev_mmu_ops;
473 ret = mmu_notifier_register(&priv->mn, priv->mm);
474 mmput(priv->mm);
475 }
476
477 if (ret) {
478 kfree(priv);
479 return ret;
480 }
481
482 flip->private_data = priv;
483 pr_debug("priv %p\n", priv);
484
485 return 0;
486 }
487
488 static int gntdev_release(struct inode *inode, struct file *flip)
489 {
490 struct gntdev_priv *priv = flip->private_data;
491 struct grant_map *map;
492
493 pr_debug("priv %p\n", priv);
494
495 while (!list_empty(&priv->maps)) {
496 map = list_entry(priv->maps.next, struct grant_map, next);
497 list_del(&map->next);
498 gntdev_put_map(map);
499 }
500
501 if (use_ptemod)
502 mmu_notifier_unregister(&priv->mn, priv->mm);
503 kfree(priv);
504 return 0;
505 }
506
507 static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
508 struct ioctl_gntdev_map_grant_ref __user *u)
509 {
510 struct ioctl_gntdev_map_grant_ref op;
511 struct grant_map *map;
512 int err;
513
514 if (copy_from_user(&op, u, sizeof(op)) != 0)
515 return -EFAULT;
516 pr_debug("priv %p, add %d\n", priv, op.count);
517 if (unlikely(op.count <= 0))
518 return -EINVAL;
519
520 err = -ENOMEM;
521 map = gntdev_alloc_map(priv, op.count);
522 if (!map)
523 return err;
524
525 if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) {
526 pr_debug("can't map: over limit\n");
527 gntdev_put_map(map);
528 return err;
529 }
530
531 if (copy_from_user(map->grants, &u->refs,
532 sizeof(map->grants[0]) * op.count) != 0) {
533 gntdev_put_map(map);
534 return err;
535 }
536
537 spin_lock(&priv->lock);
538 gntdev_add_map(priv, map);
539 op.index = map->index << PAGE_SHIFT;
540 spin_unlock(&priv->lock);
541
542 if (copy_to_user(u, &op, sizeof(op)) != 0)
543 return -EFAULT;
544
545 return 0;
546 }
547
548 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
549 struct ioctl_gntdev_unmap_grant_ref __user *u)
550 {
551 struct ioctl_gntdev_unmap_grant_ref op;
552 struct grant_map *map;
553 int err = -ENOENT;
554
555 if (copy_from_user(&op, u, sizeof(op)) != 0)
556 return -EFAULT;
557 pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
558
559 spin_lock(&priv->lock);
560 map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
561 if (map) {
562 list_del(&map->next);
563 err = 0;
564 }
565 spin_unlock(&priv->lock);
566 if (map)
567 gntdev_put_map(map);
568 return err;
569 }
570
571 static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
572 struct ioctl_gntdev_get_offset_for_vaddr __user *u)
573 {
574 struct ioctl_gntdev_get_offset_for_vaddr op;
575 struct vm_area_struct *vma;
576 struct grant_map *map;
577
578 if (copy_from_user(&op, u, sizeof(op)) != 0)
579 return -EFAULT;
580 pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
581
582 vma = find_vma(current->mm, op.vaddr);
583 if (!vma || vma->vm_ops != &gntdev_vmops)
584 return -EINVAL;
585
586 map = vma->vm_private_data;
587 if (!map)
588 return -EINVAL;
589
590 op.offset = map->index << PAGE_SHIFT;
591 op.count = map->count;
592
593 if (copy_to_user(u, &op, sizeof(op)) != 0)
594 return -EFAULT;
595 return 0;
596 }
597
598 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
599 {
600 struct ioctl_gntdev_unmap_notify op;
601 struct grant_map *map;
602 int rc;
603
604 if (copy_from_user(&op, u, sizeof(op)))
605 return -EFAULT;
606
607 if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
608 return -EINVAL;
609
610 spin_lock(&priv->lock);
611
612 list_for_each_entry(map, &priv->maps, next) {
613 uint64_t begin = map->index << PAGE_SHIFT;
614 uint64_t end = (map->index + map->count) << PAGE_SHIFT;
615 if (op.index >= begin && op.index < end)
616 goto found;
617 }
618 rc = -ENOENT;
619 goto unlock_out;
620
621 found:
622 if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
623 (map->flags & GNTMAP_readonly)) {
624 rc = -EINVAL;
625 goto unlock_out;
626 }
627
628 map->notify.flags = op.action;
629 map->notify.addr = op.index - (map->index << PAGE_SHIFT);
630 map->notify.event = op.event_channel_port;
631 rc = 0;
632 unlock_out:
633 spin_unlock(&priv->lock);
634 return rc;
635 }
636
637 static long gntdev_ioctl(struct file *flip,
638 unsigned int cmd, unsigned long arg)
639 {
640 struct gntdev_priv *priv = flip->private_data;
641 void __user *ptr = (void __user *)arg;
642
643 switch (cmd) {
644 case IOCTL_GNTDEV_MAP_GRANT_REF:
645 return gntdev_ioctl_map_grant_ref(priv, ptr);
646
647 case IOCTL_GNTDEV_UNMAP_GRANT_REF:
648 return gntdev_ioctl_unmap_grant_ref(priv, ptr);
649
650 case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
651 return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
652
653 case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
654 return gntdev_ioctl_notify(priv, ptr);
655
656 default:
657 pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
658 return -ENOIOCTLCMD;
659 }
660
661 return 0;
662 }
663
664 static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
665 {
666 struct gntdev_priv *priv = flip->private_data;
667 int index = vma->vm_pgoff;
668 int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
669 struct grant_map *map;
670 int i, err = -EINVAL;
671
672 if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
673 return -EINVAL;
674
675 pr_debug("map %d+%d at %lx (pgoff %lx)\n",
676 index, count, vma->vm_start, vma->vm_pgoff);
677
678 spin_lock(&priv->lock);
679 map = gntdev_find_map_index(priv, index, count);
680 if (!map)
681 goto unlock_out;
682 if (use_ptemod && map->vma)
683 goto unlock_out;
684 if (use_ptemod && priv->mm != vma->vm_mm) {
685 printk(KERN_WARNING "Huh? Other mm?\n");
686 goto unlock_out;
687 }
688
689 atomic_inc(&map->users);
690
691 vma->vm_ops = &gntdev_vmops;
692
693 vma->vm_flags |= VM_RESERVED|VM_DONTEXPAND;
694
695 if (use_ptemod)
696 vma->vm_flags |= VM_DONTCOPY|VM_PFNMAP;
697
698 vma->vm_private_data = map;
699
700 if (use_ptemod)
701 map->vma = vma;
702
703 if (map->flags) {
704 if ((vma->vm_flags & VM_WRITE) &&
705 (map->flags & GNTMAP_readonly))
706 goto out_unlock_put;
707 } else {
708 map->flags = GNTMAP_host_map;
709 if (!(vma->vm_flags & VM_WRITE))
710 map->flags |= GNTMAP_readonly;
711 }
712
713 spin_unlock(&priv->lock);
714
715 if (use_ptemod) {
716 err = apply_to_page_range(vma->vm_mm, vma->vm_start,
717 vma->vm_end - vma->vm_start,
718 find_grant_ptes, map);
719 if (err) {
720 printk(KERN_WARNING "find_grant_ptes() failure.\n");
721 goto out_put_map;
722 }
723 }
724
725 err = map_grant_pages(map);
726 if (err)
727 goto out_put_map;
728
729 if (!use_ptemod) {
730 for (i = 0; i < count; i++) {
731 err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE,
732 map->pages[i]);
733 if (err)
734 goto out_put_map;
735 }
736 }
737
738 return 0;
739
740 unlock_out:
741 spin_unlock(&priv->lock);
742 return err;
743
744 out_unlock_put:
745 spin_unlock(&priv->lock);
746 out_put_map:
747 if (use_ptemod)
748 map->vma = NULL;
749 gntdev_put_map(map);
750 return err;
751 }
752
753 static const struct file_operations gntdev_fops = {
754 .owner = THIS_MODULE,
755 .open = gntdev_open,
756 .release = gntdev_release,
757 .mmap = gntdev_mmap,
758 .unlocked_ioctl = gntdev_ioctl
759 };
760
761 static struct miscdevice gntdev_miscdev = {
762 .minor = MISC_DYNAMIC_MINOR,
763 .name = "xen/gntdev",
764 .fops = &gntdev_fops,
765 };
766
767 /* ------------------------------------------------------------------ */
768
769 static int __init gntdev_init(void)
770 {
771 int err;
772
773 if (!xen_domain())
774 return -ENODEV;
775
776 use_ptemod = xen_pv_domain();
777
778 err = misc_register(&gntdev_miscdev);
779 if (err != 0) {
780 printk(KERN_ERR "Could not register gntdev device\n");
781 return err;
782 }
783 return 0;
784 }
785
786 static void __exit gntdev_exit(void)
787 {
788 misc_deregister(&gntdev_miscdev);
789 }
790
791 module_init(gntdev_init);
792 module_exit(gntdev_exit);
793
794 /* ------------------------------------------------------------------ */
Linux Btrfs Development