aboutsummaryrefslogtreecommitdiffstats
path: root/mm/vmalloc.c
blob: 1133dd3aafcf4c02e5b2d109b02f45013b7d9d11 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
/*
 *  linux/mm/vmalloc.c
 *
 *  Copyright (C) 1993  Linus Torvalds
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 *  SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
 *  Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
 *  Numa awareness, Christoph Lameter, SGI, June 2005
 */

#include <linux/mm.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>

#include <linux/vmalloc.h>

#include <asm/uaccess.h>
#include <asm/tlbflush.h>


DEFINE_RWLOCK(vmlist_lock);
struct vm_struct *vmlist;

static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
			    int node);

static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
{
	pte_t *pte;

	pte = pte_offset_kernel(pmd, addr);
	do {
		pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
		WARN_ON(!pte_none(ptent) && !pte_present(ptent));
	} while (pte++, addr += PAGE_SIZE, addr != end);
}

static inline void vunmap_pmd_range(pud_t *pud, unsigned long addr,
						unsigned long end)
{
	pmd_t *pmd;
	unsigned long next;

	pmd = pmd_offset(pud, addr);
	do {
		next = pmd_addr_end(addr, end);
		if (pmd_none_or_clear_bad(pmd))
			continue;
		vunmap_pte_range(pmd, addr, next);
	} while (pmd++, addr = next, addr != end);
}

static inline void vunmap_pud_range(pgd_t *pgd, unsigned long addr,
						unsigned long end)
{
	pud_t *pud;
	unsigned long next;

	pud = pud_offset(pgd, addr);
	do {
		next = pud_addr_end(addr, end);
		if (pud_none_or_clear_bad(pud))
			continue;
		vunmap_pmd_range(pud, addr, next);
	} while (pud++, addr = next, addr != end);
}

void unmap_vm_area(struct vm_struct *area)
{
	pgd_t *pgd;
	unsigned long next;
	unsigned long addr = (unsigned long) area->addr;
	unsigned long end = addr + area->size;

	BUG_ON(addr >= end);
	pgd = pgd_offset_k(addr);
	flush_cache_vunmap(addr, end);
	do {
		next = pgd_addr_end(addr, end);
		if (pgd_none_or_clear_bad(pgd))
			continue;
		vunmap_pud_range(pgd, addr, next);
	} while (pgd++, addr = next, addr != end);
	flush_tlb_kernel_range((unsigned long) area->addr, end);
}

static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
			unsigned long end, pgprot_t prot, struct page ***pages)
{
	pte_t *pte;

	pte = pte_alloc_kernel(pmd, addr);
	if (!pte)
		return -ENOMEM;
	do {
		struct page *page = **pages;
		WARN_ON(!pte_none(*pte));
		if (!page)
			return -ENOMEM;
		set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
		(*pages)++;
	} while (pte++, addr += PAGE_SIZE, addr != end);
	return 0;
}

static inline int vmap_pmd_range(pud_t *pud, unsigned long addr,
			unsigned long end, pgprot_t prot, struct page ***pages)
{
	pmd_t *pmd;
	unsigned long next;

	pmd = pmd_alloc(&init_mm, pud, addr);
	if (!pmd)
		return -ENOMEM;
	do {
		next = pmd_addr_end(addr, end);
		if (vmap_pte_range(pmd, addr, next, prot, pages))
			return -ENOMEM;
	} while (pmd++, addr = next, addr != end);
	return 0;
}

static inline int vmap_pud_range(pgd_t *pgd, unsigned long addr,
			unsigned long end, pgprot_t prot, struct page ***pages)
{
	pud_t *pud;
	unsigned long next;

	pud = pud_alloc(&init_mm, pgd, addr);
	if (!pud)
		return -ENOMEM;
	do {
		next = pud_addr_end(addr, end);
		if (vmap_pmd_range(pud, addr, next, prot, pages))
			return -ENOMEM;
	} while (pud++, addr = next, addr != end);
	return 0;
}

int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
{
	pgd_t *pgd;
	unsigned long next;
	unsigned long addr = (unsigned long) area->addr;
	unsigned long end = addr + area->size - PAGE_SIZE;
	int err;

	BUG_ON(addr >= end);
	pgd = pgd_offset_k(addr);
	do {
		next = pgd_addr_end(addr, end);
		err = vmap_pud_range(pgd, addr, next, prot, pages);
		if (err)
			break;
	} while (pgd++, addr = next, addr != end);
	flush_cache_vmap((unsigned long) area->addr, end);
	return err;
}

struct vm_struct *__get_vm_area_node(unsigned long size, unsigned long flags,
				unsigned long start, unsigned long end, int node)
{
	struct vm_struct **p, *tmp, *area;
	unsigned long align = 1;
	unsigned long addr;

	if (flags & VM_IOREMAP) {
		int bit = fls(size);

		if (bit > IOREMAP_MAX_ORDER)
			bit = IOREMAP_MAX_ORDER;
		else if (bit < PAGE_SHIFT)
			bit = PAGE_SHIFT;

		align = 1ul << bit;
	}
	addr = ALIGN(start, align);
	size = PAGE_ALIGN(size);

	area = kmalloc_node(sizeof(*area), GFP_KERNEL, node);
	if (unlikely(!area))
		return NULL;

	if (unlikely(!size)) {
		kfree (area);
		return NULL;
	}

	/*
	 * We always allocate a guard page.
	 */
	size += PAGE_SIZE;

	write_lock(&vmlist_lock);
	for (p = &vmlist; (tmp = *p) != NULL ;p = &tmp->next) {
		if ((unsigned long)tmp->addr < addr) {
			if((unsigned long)tmp->addr + tmp->size >= addr)
				addr = ALIGN(tmp->size + 
					     (unsigned long)tmp->addr, align);
			continue;
		}
		if ((size + addr) < addr)
			goto out;
		if (size + addr <= (unsigned long)tmp->addr)
			goto found;
		addr = ALIGN(tmp->size + (unsigned long)tmp->addr, align);
		if (addr > end - size)
			goto out;
	}

found:
	area->next = *p;
	*p = area;

	area->flags = flags;
	area->addr = (void *)addr;
	area->size = size;
	area->pages = NULL;
	area->nr_pages = 0;
	area->phys_addr = 0;
	write_unlock(&vmlist_lock);

	return area;

out:
	write_unlock(&vmlist_lock);
	kfree(area);
	if (printk_ratelimit())
		printk(KERN_WARNING "allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.\n");
	return NULL;
}

struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
				unsigned long start, unsigned long end)
{
	return __get_vm_area_node(size, flags, start, end, -1);
}

/**
 *	get_vm_area  -  reserve a contingous kernel virtual area
 *	@size:		size of the area
 *	@flags:		%VM_IOREMAP for I/O mappings or VM_ALLOC
 *
 *	Search an area of @size in the kernel virtual mapping area,
 *	and reserved it for out purposes.  Returns the area descriptor
 *	on success or %NULL on failure.
 */
struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
{
	return __get_vm_area(size, flags, VMALLOC_START, VMALLOC_END);
}

struct vm_struct *get_vm_area_node(unsigned long size, unsigned long flags, int node)
{
	return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END, node);
}

/* Caller must hold vmlist_lock */
static struct vm_struct *__find_vm_area(void *addr)
{
	struct vm_struct *tmp;

	for (tmp = vmlist; tmp != NULL; tmp = tmp->next) {
		 if (tmp->addr == addr)
			break;
	}

	return tmp;
}

/* Caller must hold vmlist_lock */
static struct vm_struct *__remove_vm_area(void *addr)
{
	struct vm_struct **p, *tmp;

	for (p = &vmlist ; (tmp = *p) != NULL ;p = &tmp->next) {
		 if (tmp->addr == addr)
			 goto found;
	}
	return NULL;

found:
	unmap_vm_area(tmp);
	*p = tmp->next;

	/*
	 * Remove the guard page.
	 */
	tmp->size -= PAGE_SIZE;
	return tmp;
}

/**
 *	remove_vm_area  -  find and remove a contingous kernel virtual area
 *	@addr:		base address
 *
 *	Search for the kernel VM area starting at @addr, and remove it.
 *	This function returns the found VM area, but using it is NOT safe
 *	on SMP machines, except for its size or flags.
 */
struct vm_struct *remove_vm_area(void *addr)
{
	struct vm_struct *v;
	write_lock(&vmlist_lock);
	v = __remove_vm_area(addr);
	write_unlock(&vmlist_lock);
	return v;
}

void __vunmap(void *addr, int deallocate_pages)
{
	struct vm_struct *area;

	if (!addr)
		return;

	if ((PAGE_SIZE-1) & (unsigned long)addr) {
		printk(KERN_ERR "Trying to vfree() bad address (%p)\n", addr);
		WARN_ON(1);
		return;
	}

	area = remove_vm_area(addr);
	if (unlikely(!area)) {
		printk(KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
				addr);
		WARN_ON(1);
		return;
	}

	debug_check_no_locks_freed(addr, area->size);

	if (deallocate_pages) {
		int i;

		for (i = 0; i < area->nr_pages; i++) {
			BUG_ON(!area->pages[i]);
			__free_page(area->pages[i]);
		}

		if (area->flags & VM_VPAGES)
			vfree(area->pages);
		else
			kfree(area->pages);
	}

	kfree(area);
	return;
}

/**
 *	vfree  -  release memory allocated by vmalloc()
 *	@addr:		memory base address
 *
 *	Free the virtually contiguous memory area starting at @addr, as
 *	obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
 *	NULL, no operation is performed.
 *
 *	Must not be called in interrupt context.
 */
void vfree(void *addr)
{
	BUG_ON(in_interrupt());
	__vunmap(addr, 1);
}
EXPORT_SYMBOL(vfree);

/**
 *	vunmap  -  release virtual mapping obtained by vmap()
 *	@addr:		memory base address
 *
 *	Free the virtually contiguous memory area starting at @addr,
 *	which was created from the page array passed to vmap().
 *
 *	Must not be called in interrupt context.
 */
void vunmap(void *addr)
{
	BUG_ON(in_interrupt());
	__vunmap(addr, 0);
}
EXPORT_SYMBOL(vunmap);

/**
 *	vmap  -  map an array of pages into virtually contiguous space
 *	@pages:		array of page pointers
 *	@count:		number of pages to map
 *	@flags:		vm_area->flags
 *	@prot:		page protection for the mapping
 *
 *	Maps @count pages from @pages into contiguous kernel virtual
 *	space.
 */
void *vmap(struct page **pages, unsigned int count,
		unsigned long flags, pgprot_t prot)
{
	struct vm_struct *area;

	if (count > num_physpages)
		return NULL;

	area = get_vm_area((count << PAGE_SHIFT), flags);
	if (!area)
		return NULL;
	if (map_vm_area(area, prot, &pages)) {
		vunmap(area->addr);
		return NULL;
	}

	return area->addr;
}
EXPORT_SYMBOL(vmap);

void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
				pgprot_t prot, int node)
{
	struct page **pages;
	unsigned int nr_pages, array_size, i;

	nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
	array_size = (nr_pages * sizeof(struct page *));

	area->nr_pages = nr_pages;
	/* Please note that the recursion is strictly bounded. */
	if (array_size > PAGE_SIZE) {
		pages = __vmalloc_node(array_size, gfp_mask, PAGE_KERNEL, node);
		area->flags |= VM_VPAGES;
	} else {
		pages = kmalloc_node(array_size,
				(gfp_mask & ~(__GFP_HIGHMEM | __GFP_ZERO)),
				node);
	}
	area->pages = pages;
	if (!area->pages) {
		remove_vm_area(area->addr);
		kfree(area);
		return NULL;
	}
	memset(area->pages, 0, array_size);

	for (i = 0; i < area->nr_pages; i++) {
		if (node < 0)
			area->pages[i] = alloc_page(gfp_mask);
		else
			area->pages[i] = alloc_pages_node(node, gfp_mask, 0);
		if (unlikely(!area->pages[i])) {
			/* Successfully allocated i pages, free them in __vunmap() */
			area->nr_pages = i;
			goto fail;
		}
	}

	if (map_vm_area(area, prot, &pages))
		goto fail;
	return area->addr;

fail:
	vfree(area->addr);
	return NULL;
}

void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
{
	return __vmalloc_area_node(area, gfp_mask, prot, -1);
}

/**
 *	__vmalloc_node  -  allocate virtually contiguous memory
 *	@size:		allocation size
 *	@gfp_mask:	flags for the page level allocator
 *	@prot:		protection mask for the allocated pages
 *	@node:		node to use for allocation or -1
 *
 *	Allocate enough pages to cover @size from the page level
 *	allocator with @gfp_mask flags.  Map them into contiguous
 *	kernel virtual space, using a pagetable protection of @prot.
 */
static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
			    int node)
{
	struct vm_struct *area;

	size = PAGE_ALIGN(size);
	if (!size || (size >> PAGE_SHIFT) > num_physpages)
		return NULL;

	area = get_vm_area_node(size, VM_ALLOC, node);
	if (!area)
		return NULL;

	return __vmalloc_area_node(area, gfp_mask, prot, node);
}

void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
{
	return __vmalloc_node(size, gfp_mask, prot, -1);
}
EXPORT_SYMBOL(__vmalloc);

/**
 *	vmalloc  -  allocate virtually contiguous memory
 *	@size:		allocation size
 *	Allocate enough pages to cover @size from the page level
 *	allocator and map them into contiguous kernel virtual space.
 *
 *	For tight control over page level allocator and protection flags
 *	use __vmalloc() instead.
 */
void *vmalloc(unsigned long size)
{
	return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
}
EXPORT_SYMBOL(vmalloc);

/**
 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
 * @size: allocation size
 *
 * The resulting memory area is zeroed so it can be mapped to userspace
 * without leaking data.
 */
void *vmalloc_user(unsigned long size)
{
	struct vm_struct *area;
	void *ret;

	ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
	write_lock(&vmlist_lock);
	area = __find_vm_area(ret);
	area->flags |= VM_USERMAP;
	write_unlock(&vmlist_lock);

	return ret;
}
EXPORT_SYMBOL(vmalloc_user);

/**
 *	vmalloc_node  -  allocate memory on a specific node
 *	@size:		allocation size
 *	@node:		numa node
 *
 *	Allocate enough pages to cover @size from the page level
 *	allocator and map them into contiguous kernel virtual space.
 *
 *	For tight control over page level allocator and protection flags
 *	use __vmalloc() instead.
 */
void *vmalloc_node(unsigned long size, int node)
{
	return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL, node);
}
EXPORT_SYMBOL(vmalloc_node);

#ifndef PAGE_KERNEL_EXEC
# define PAGE_KERNEL_EXEC PAGE_KERNEL
#endif

/**
 *	vmalloc_exec  -  allocate virtually contiguous, executable memory
 *	@size:		allocation size
 *
 *	Kernel-internal function to allocate enough pages to cover @size
 *	the page level allocator and map them into contiguous and
 *	executable kernel virtual space.
 *
 *	For tight control over page level allocator and protection flags
 *	use __vmalloc() instead.
 */

void *vmalloc_exec(unsigned long size)
{
	return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
}

/**
 *	vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
 *	@size:		allocation size
 *
 *	Allocate enough 32bit PA addressable pages to cover @size from the
 *	page level allocator and map them into contiguous kernel virtual space.
 */
void *vmalloc_32(unsigned long size)
{
	return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
}
EXPORT_SYMBOL(vmalloc_32);

/**
 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
 *	@size:		allocation size
 *
 * The resulting memory area is 32bit addressable and zeroed so it can be
 * mapped to userspace without leaking data.
 */
void *vmalloc_32_user(unsigned long size)
{
	struct vm_struct *area;
	void *ret;

	ret = __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
	write_lock(&vmlist_lock);
	area = __find_vm_area(ret);
	area->flags |= VM_USERMAP;
	write_unlock(&vmlist_lock);

	return ret;
}
EXPORT_SYMBOL(vmalloc_32_user);

long vread(char *buf, char *addr, unsigned long count)
{
	struct vm_struct *tmp;
	char *vaddr, *buf_start = buf;
	unsigned long n;

	/* Don't allow overflow */
	if ((unsigned long) addr + count < count)
		count = -(unsigned long) addr;

	read_lock(&vmlist_lock);
	for (tmp = vmlist; tmp; tmp = tmp->next) {
		vaddr = (char *) tmp->addr;
		if (addr >= vaddr + tmp->size - PAGE_SIZE)
			continue;
		while (addr < vaddr) {
			if (count == 0)
				goto finished;
			*buf = '\0';
			buf++;
			addr++;
			count--;
		}
		n = vaddr + tmp->size - PAGE_SIZE - addr;
		do {
			if (count == 0)
				goto finished;
			*buf = *addr;
			buf++;
			addr++;
			count--;
		} while (--n > 0);
	}
finished:
	read_unlock(&vmlist_lock);
	return buf - buf_start;
}

long vwrite(char *buf, char *addr, unsigned long count)
{
	struct vm_struct *tmp;
	char *vaddr, *buf_start = buf;
	unsigned long n;

	/* Don't allow overflow */
	if ((unsigned long) addr + count < count)
		count = -(unsigned long) addr;

	read_lock(&vmlist_lock);
	for (tmp = vmlist; tmp; tmp = tmp->next) {
		vaddr = (char *) tmp->addr;
		if (addr >= vaddr + tmp->size - PAGE_SIZE)
			continue;
		while (addr < vaddr) {
			if (count == 0)
				goto finished;
			buf++;
			addr++;
			count--;
		}
		n = vaddr + tmp->size - PAGE_SIZE - addr;
		do {
			if (count == 0)
				goto finished;
			*addr = *buf;
			buf++;
			addr++;
			count--;
		} while (--n > 0);
	}
finished:
	read_unlock(&vmlist_lock);
	return buf - buf_start;
}

/**
 *	remap_vmalloc_range  -  map vmalloc pages to userspace
 *	@vma:		vma to cover (map full range of vma)
 *	@addr:		vmalloc memory
 *	@pgoff:		number of pages into addr before first page to map
 *	@returns:	0 for success, -Exxx on failure
 *
 *	This function checks that addr is a valid vmalloc'ed area, and
 *	that it is big enough to cover the vma. Will return failure if
 *	that criteria isn't met.
 *
 *	Similar to remap_pfn_range (see mm/memory.c)
 */
int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
						unsigned long pgoff)
{
	struct vm_struct *area;
	unsigned long uaddr = vma->vm_start;
	unsigned long usize = vma->vm_end - vma->vm_start;
	int ret;

	if ((PAGE_SIZE-1) & (unsigned long)addr)
		return -EINVAL;

	read_lock(&vmlist_lock);
	area = __find_vm_area(addr);
	if (!area)
		goto out_einval_locked;

	if (!(area->flags & VM_USERMAP))
		goto out_einval_locked;

	if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
		goto out_einval_locked;
	read_unlock(&vmlist_lock);

	addr += pgoff << PAGE_SHIFT;
	do {
		struct page *page = vmalloc_to_page(addr);
		ret = vm_insert_page(vma, uaddr, page);
		if (ret)
			return ret;

		uaddr += PAGE_SIZE;
		addr += PAGE_SIZE;
		usize -= PAGE_SIZE;
	} while (usize > 0);

	/* Prevent "things" like memory migration? VM_flags need a cleanup... */
	vma->vm_flags |= VM_RESERVED;

	return ret;

out_einval_locked:
	read_unlock(&vmlist_lock);
	return -EINVAL;
}
EXPORT_SYMBOL(remap_vmalloc_range);