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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/vmalloc.c | |
3 | * | |
4 | * Copyright (C) 1993 Linus Torvalds | |
5 | * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 | |
6 | * SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000 | |
7 | * Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002 | |
930fc45a | 8 | * Numa awareness, Christoph Lameter, SGI, June 2005 |
1da177e4 LT |
9 | */ |
10 | ||
11 | #include <linux/mm.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/highmem.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/spinlock.h> | |
16 | #include <linux/interrupt.h> | |
17 | ||
18 | #include <linux/vmalloc.h> | |
19 | ||
20 | #include <asm/uaccess.h> | |
21 | #include <asm/tlbflush.h> | |
22 | ||
23 | ||
24 | DEFINE_RWLOCK(vmlist_lock); | |
25 | struct vm_struct *vmlist; | |
26 | ||
27 | static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end) | |
28 | { | |
29 | pte_t *pte; | |
30 | ||
31 | pte = pte_offset_kernel(pmd, addr); | |
32 | do { | |
33 | pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte); | |
34 | WARN_ON(!pte_none(ptent) && !pte_present(ptent)); | |
35 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
36 | } | |
37 | ||
38 | static inline void vunmap_pmd_range(pud_t *pud, unsigned long addr, | |
39 | unsigned long end) | |
40 | { | |
41 | pmd_t *pmd; | |
42 | unsigned long next; | |
43 | ||
44 | pmd = pmd_offset(pud, addr); | |
45 | do { | |
46 | next = pmd_addr_end(addr, end); | |
47 | if (pmd_none_or_clear_bad(pmd)) | |
48 | continue; | |
49 | vunmap_pte_range(pmd, addr, next); | |
50 | } while (pmd++, addr = next, addr != end); | |
51 | } | |
52 | ||
53 | static inline void vunmap_pud_range(pgd_t *pgd, unsigned long addr, | |
54 | unsigned long end) | |
55 | { | |
56 | pud_t *pud; | |
57 | unsigned long next; | |
58 | ||
59 | pud = pud_offset(pgd, addr); | |
60 | do { | |
61 | next = pud_addr_end(addr, end); | |
62 | if (pud_none_or_clear_bad(pud)) | |
63 | continue; | |
64 | vunmap_pmd_range(pud, addr, next); | |
65 | } while (pud++, addr = next, addr != end); | |
66 | } | |
67 | ||
68 | void unmap_vm_area(struct vm_struct *area) | |
69 | { | |
70 | pgd_t *pgd; | |
71 | unsigned long next; | |
72 | unsigned long addr = (unsigned long) area->addr; | |
73 | unsigned long end = addr + area->size; | |
74 | ||
75 | BUG_ON(addr >= end); | |
76 | pgd = pgd_offset_k(addr); | |
77 | flush_cache_vunmap(addr, end); | |
78 | do { | |
79 | next = pgd_addr_end(addr, end); | |
80 | if (pgd_none_or_clear_bad(pgd)) | |
81 | continue; | |
82 | vunmap_pud_range(pgd, addr, next); | |
83 | } while (pgd++, addr = next, addr != end); | |
84 | flush_tlb_kernel_range((unsigned long) area->addr, end); | |
85 | } | |
86 | ||
87 | static int vmap_pte_range(pmd_t *pmd, unsigned long addr, | |
88 | unsigned long end, pgprot_t prot, struct page ***pages) | |
89 | { | |
90 | pte_t *pte; | |
91 | ||
872fec16 | 92 | pte = pte_alloc_kernel(pmd, addr); |
1da177e4 LT |
93 | if (!pte) |
94 | return -ENOMEM; | |
95 | do { | |
96 | struct page *page = **pages; | |
97 | WARN_ON(!pte_none(*pte)); | |
98 | if (!page) | |
99 | return -ENOMEM; | |
100 | set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); | |
101 | (*pages)++; | |
102 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | static inline int vmap_pmd_range(pud_t *pud, unsigned long addr, | |
107 | unsigned long end, pgprot_t prot, struct page ***pages) | |
108 | { | |
109 | pmd_t *pmd; | |
110 | unsigned long next; | |
111 | ||
112 | pmd = pmd_alloc(&init_mm, pud, addr); | |
113 | if (!pmd) | |
114 | return -ENOMEM; | |
115 | do { | |
116 | next = pmd_addr_end(addr, end); | |
117 | if (vmap_pte_range(pmd, addr, next, prot, pages)) | |
118 | return -ENOMEM; | |
119 | } while (pmd++, addr = next, addr != end); | |
120 | return 0; | |
121 | } | |
122 | ||
123 | static inline int vmap_pud_range(pgd_t *pgd, unsigned long addr, | |
124 | unsigned long end, pgprot_t prot, struct page ***pages) | |
125 | { | |
126 | pud_t *pud; | |
127 | unsigned long next; | |
128 | ||
129 | pud = pud_alloc(&init_mm, pgd, addr); | |
130 | if (!pud) | |
131 | return -ENOMEM; | |
132 | do { | |
133 | next = pud_addr_end(addr, end); | |
134 | if (vmap_pmd_range(pud, addr, next, prot, pages)) | |
135 | return -ENOMEM; | |
136 | } while (pud++, addr = next, addr != end); | |
137 | return 0; | |
138 | } | |
139 | ||
140 | int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages) | |
141 | { | |
142 | pgd_t *pgd; | |
143 | unsigned long next; | |
144 | unsigned long addr = (unsigned long) area->addr; | |
145 | unsigned long end = addr + area->size - PAGE_SIZE; | |
146 | int err; | |
147 | ||
148 | BUG_ON(addr >= end); | |
149 | pgd = pgd_offset_k(addr); | |
1da177e4 LT |
150 | do { |
151 | next = pgd_addr_end(addr, end); | |
152 | err = vmap_pud_range(pgd, addr, next, prot, pages); | |
153 | if (err) | |
154 | break; | |
155 | } while (pgd++, addr = next, addr != end); | |
1da177e4 LT |
156 | flush_cache_vmap((unsigned long) area->addr, end); |
157 | return err; | |
158 | } | |
159 | ||
930fc45a CL |
160 | struct vm_struct *__get_vm_area_node(unsigned long size, unsigned long flags, |
161 | unsigned long start, unsigned long end, int node) | |
1da177e4 LT |
162 | { |
163 | struct vm_struct **p, *tmp, *area; | |
164 | unsigned long align = 1; | |
165 | unsigned long addr; | |
166 | ||
167 | if (flags & VM_IOREMAP) { | |
168 | int bit = fls(size); | |
169 | ||
170 | if (bit > IOREMAP_MAX_ORDER) | |
171 | bit = IOREMAP_MAX_ORDER; | |
172 | else if (bit < PAGE_SHIFT) | |
173 | bit = PAGE_SHIFT; | |
174 | ||
175 | align = 1ul << bit; | |
176 | } | |
177 | addr = ALIGN(start, align); | |
178 | size = PAGE_ALIGN(size); | |
179 | ||
930fc45a | 180 | area = kmalloc_node(sizeof(*area), GFP_KERNEL, node); |
1da177e4 LT |
181 | if (unlikely(!area)) |
182 | return NULL; | |
183 | ||
184 | if (unlikely(!size)) { | |
185 | kfree (area); | |
186 | return NULL; | |
187 | } | |
188 | ||
189 | /* | |
190 | * We always allocate a guard page. | |
191 | */ | |
192 | size += PAGE_SIZE; | |
193 | ||
194 | write_lock(&vmlist_lock); | |
195 | for (p = &vmlist; (tmp = *p) != NULL ;p = &tmp->next) { | |
196 | if ((unsigned long)tmp->addr < addr) { | |
197 | if((unsigned long)tmp->addr + tmp->size >= addr) | |
198 | addr = ALIGN(tmp->size + | |
199 | (unsigned long)tmp->addr, align); | |
200 | continue; | |
201 | } | |
202 | if ((size + addr) < addr) | |
203 | goto out; | |
204 | if (size + addr <= (unsigned long)tmp->addr) | |
205 | goto found; | |
206 | addr = ALIGN(tmp->size + (unsigned long)tmp->addr, align); | |
207 | if (addr > end - size) | |
208 | goto out; | |
209 | } | |
210 | ||
211 | found: | |
212 | area->next = *p; | |
213 | *p = area; | |
214 | ||
215 | area->flags = flags; | |
216 | area->addr = (void *)addr; | |
217 | area->size = size; | |
218 | area->pages = NULL; | |
219 | area->nr_pages = 0; | |
220 | area->phys_addr = 0; | |
221 | write_unlock(&vmlist_lock); | |
222 | ||
223 | return area; | |
224 | ||
225 | out: | |
226 | write_unlock(&vmlist_lock); | |
227 | kfree(area); | |
228 | if (printk_ratelimit()) | |
229 | printk(KERN_WARNING "allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.\n"); | |
230 | return NULL; | |
231 | } | |
232 | ||
930fc45a CL |
233 | struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, |
234 | unsigned long start, unsigned long end) | |
235 | { | |
236 | return __get_vm_area_node(size, flags, start, end, -1); | |
237 | } | |
238 | ||
1da177e4 LT |
239 | /** |
240 | * get_vm_area - reserve a contingous kernel virtual area | |
241 | * | |
242 | * @size: size of the area | |
243 | * @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC | |
244 | * | |
245 | * Search an area of @size in the kernel virtual mapping area, | |
246 | * and reserved it for out purposes. Returns the area descriptor | |
247 | * on success or %NULL on failure. | |
248 | */ | |
249 | struct vm_struct *get_vm_area(unsigned long size, unsigned long flags) | |
250 | { | |
251 | return __get_vm_area(size, flags, VMALLOC_START, VMALLOC_END); | |
252 | } | |
253 | ||
930fc45a CL |
254 | struct vm_struct *get_vm_area_node(unsigned long size, unsigned long flags, int node) |
255 | { | |
256 | return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END, node); | |
257 | } | |
258 | ||
7856dfeb AK |
259 | /* Caller must hold vmlist_lock */ |
260 | struct vm_struct *__remove_vm_area(void *addr) | |
1da177e4 LT |
261 | { |
262 | struct vm_struct **p, *tmp; | |
263 | ||
1da177e4 LT |
264 | for (p = &vmlist ; (tmp = *p) != NULL ;p = &tmp->next) { |
265 | if (tmp->addr == addr) | |
266 | goto found; | |
267 | } | |
1da177e4 LT |
268 | return NULL; |
269 | ||
270 | found: | |
271 | unmap_vm_area(tmp); | |
272 | *p = tmp->next; | |
1da177e4 LT |
273 | |
274 | /* | |
275 | * Remove the guard page. | |
276 | */ | |
277 | tmp->size -= PAGE_SIZE; | |
278 | return tmp; | |
279 | } | |
280 | ||
7856dfeb AK |
281 | /** |
282 | * remove_vm_area - find and remove a contingous kernel virtual area | |
283 | * | |
284 | * @addr: base address | |
285 | * | |
286 | * Search for the kernel VM area starting at @addr, and remove it. | |
287 | * This function returns the found VM area, but using it is NOT safe | |
288 | * on SMP machines, except for its size or flags. | |
289 | */ | |
290 | struct vm_struct *remove_vm_area(void *addr) | |
291 | { | |
292 | struct vm_struct *v; | |
293 | write_lock(&vmlist_lock); | |
294 | v = __remove_vm_area(addr); | |
295 | write_unlock(&vmlist_lock); | |
296 | return v; | |
297 | } | |
298 | ||
1da177e4 LT |
299 | void __vunmap(void *addr, int deallocate_pages) |
300 | { | |
301 | struct vm_struct *area; | |
302 | ||
303 | if (!addr) | |
304 | return; | |
305 | ||
306 | if ((PAGE_SIZE-1) & (unsigned long)addr) { | |
307 | printk(KERN_ERR "Trying to vfree() bad address (%p)\n", addr); | |
308 | WARN_ON(1); | |
309 | return; | |
310 | } | |
311 | ||
312 | area = remove_vm_area(addr); | |
313 | if (unlikely(!area)) { | |
314 | printk(KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n", | |
315 | addr); | |
316 | WARN_ON(1); | |
317 | return; | |
318 | } | |
319 | ||
320 | if (deallocate_pages) { | |
321 | int i; | |
322 | ||
323 | for (i = 0; i < area->nr_pages; i++) { | |
5aae277e | 324 | BUG_ON(!area->pages[i]); |
1da177e4 LT |
325 | __free_page(area->pages[i]); |
326 | } | |
327 | ||
328 | if (area->nr_pages > PAGE_SIZE/sizeof(struct page *)) | |
329 | vfree(area->pages); | |
330 | else | |
331 | kfree(area->pages); | |
332 | } | |
333 | ||
334 | kfree(area); | |
335 | return; | |
336 | } | |
337 | ||
338 | /** | |
339 | * vfree - release memory allocated by vmalloc() | |
340 | * | |
341 | * @addr: memory base address | |
342 | * | |
343 | * Free the virtually contiguous memory area starting at @addr, as | |
80e93eff PE |
344 | * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is |
345 | * NULL, no operation is performed. | |
1da177e4 | 346 | * |
80e93eff | 347 | * Must not be called in interrupt context. |
1da177e4 LT |
348 | */ |
349 | void vfree(void *addr) | |
350 | { | |
351 | BUG_ON(in_interrupt()); | |
352 | __vunmap(addr, 1); | |
353 | } | |
1da177e4 LT |
354 | EXPORT_SYMBOL(vfree); |
355 | ||
356 | /** | |
357 | * vunmap - release virtual mapping obtained by vmap() | |
358 | * | |
359 | * @addr: memory base address | |
360 | * | |
361 | * Free the virtually contiguous memory area starting at @addr, | |
362 | * which was created from the page array passed to vmap(). | |
363 | * | |
80e93eff | 364 | * Must not be called in interrupt context. |
1da177e4 LT |
365 | */ |
366 | void vunmap(void *addr) | |
367 | { | |
368 | BUG_ON(in_interrupt()); | |
369 | __vunmap(addr, 0); | |
370 | } | |
1da177e4 LT |
371 | EXPORT_SYMBOL(vunmap); |
372 | ||
373 | /** | |
374 | * vmap - map an array of pages into virtually contiguous space | |
375 | * | |
376 | * @pages: array of page pointers | |
377 | * @count: number of pages to map | |
378 | * @flags: vm_area->flags | |
379 | * @prot: page protection for the mapping | |
380 | * | |
381 | * Maps @count pages from @pages into contiguous kernel virtual | |
382 | * space. | |
383 | */ | |
384 | void *vmap(struct page **pages, unsigned int count, | |
385 | unsigned long flags, pgprot_t prot) | |
386 | { | |
387 | struct vm_struct *area; | |
388 | ||
389 | if (count > num_physpages) | |
390 | return NULL; | |
391 | ||
392 | area = get_vm_area((count << PAGE_SHIFT), flags); | |
393 | if (!area) | |
394 | return NULL; | |
395 | if (map_vm_area(area, prot, &pages)) { | |
396 | vunmap(area->addr); | |
397 | return NULL; | |
398 | } | |
399 | ||
400 | return area->addr; | |
401 | } | |
1da177e4 LT |
402 | EXPORT_SYMBOL(vmap); |
403 | ||
930fc45a CL |
404 | void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, |
405 | pgprot_t prot, int node) | |
1da177e4 LT |
406 | { |
407 | struct page **pages; | |
408 | unsigned int nr_pages, array_size, i; | |
409 | ||
410 | nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT; | |
411 | array_size = (nr_pages * sizeof(struct page *)); | |
412 | ||
413 | area->nr_pages = nr_pages; | |
414 | /* Please note that the recursion is strictly bounded. */ | |
415 | if (array_size > PAGE_SIZE) | |
930fc45a | 416 | pages = __vmalloc_node(array_size, gfp_mask, PAGE_KERNEL, node); |
1da177e4 | 417 | else |
930fc45a | 418 | pages = kmalloc_node(array_size, (gfp_mask & ~__GFP_HIGHMEM), node); |
1da177e4 LT |
419 | area->pages = pages; |
420 | if (!area->pages) { | |
421 | remove_vm_area(area->addr); | |
422 | kfree(area); | |
423 | return NULL; | |
424 | } | |
425 | memset(area->pages, 0, array_size); | |
426 | ||
427 | for (i = 0; i < area->nr_pages; i++) { | |
930fc45a CL |
428 | if (node < 0) |
429 | area->pages[i] = alloc_page(gfp_mask); | |
430 | else | |
431 | area->pages[i] = alloc_pages_node(node, gfp_mask, 0); | |
1da177e4 LT |
432 | if (unlikely(!area->pages[i])) { |
433 | /* Successfully allocated i pages, free them in __vunmap() */ | |
434 | area->nr_pages = i; | |
435 | goto fail; | |
436 | } | |
437 | } | |
438 | ||
439 | if (map_vm_area(area, prot, &pages)) | |
440 | goto fail; | |
441 | return area->addr; | |
442 | ||
443 | fail: | |
444 | vfree(area->addr); | |
445 | return NULL; | |
446 | } | |
447 | ||
930fc45a CL |
448 | void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot) |
449 | { | |
450 | return __vmalloc_area_node(area, gfp_mask, prot, -1); | |
451 | } | |
452 | ||
1da177e4 | 453 | /** |
930fc45a | 454 | * __vmalloc_node - allocate virtually contiguous memory |
1da177e4 LT |
455 | * |
456 | * @size: allocation size | |
457 | * @gfp_mask: flags for the page level allocator | |
458 | * @prot: protection mask for the allocated pages | |
d44e0780 | 459 | * @node: node to use for allocation or -1 |
1da177e4 LT |
460 | * |
461 | * Allocate enough pages to cover @size from the page level | |
462 | * allocator with @gfp_mask flags. Map them into contiguous | |
463 | * kernel virtual space, using a pagetable protection of @prot. | |
464 | */ | |
930fc45a CL |
465 | void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot, |
466 | int node) | |
1da177e4 LT |
467 | { |
468 | struct vm_struct *area; | |
469 | ||
470 | size = PAGE_ALIGN(size); | |
471 | if (!size || (size >> PAGE_SHIFT) > num_physpages) | |
472 | return NULL; | |
473 | ||
930fc45a | 474 | area = get_vm_area_node(size, VM_ALLOC, node); |
1da177e4 LT |
475 | if (!area) |
476 | return NULL; | |
477 | ||
930fc45a | 478 | return __vmalloc_area_node(area, gfp_mask, prot, node); |
1da177e4 | 479 | } |
930fc45a | 480 | EXPORT_SYMBOL(__vmalloc_node); |
1da177e4 | 481 | |
930fc45a CL |
482 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
483 | { | |
484 | return __vmalloc_node(size, gfp_mask, prot, -1); | |
485 | } | |
1da177e4 LT |
486 | EXPORT_SYMBOL(__vmalloc); |
487 | ||
488 | /** | |
489 | * vmalloc - allocate virtually contiguous memory | |
490 | * | |
491 | * @size: allocation size | |
492 | * | |
493 | * Allocate enough pages to cover @size from the page level | |
494 | * allocator and map them into contiguous kernel virtual space. | |
495 | * | |
496 | * For tight cotrol over page level allocator and protection flags | |
497 | * use __vmalloc() instead. | |
498 | */ | |
499 | void *vmalloc(unsigned long size) | |
500 | { | |
501 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); | |
502 | } | |
1da177e4 LT |
503 | EXPORT_SYMBOL(vmalloc); |
504 | ||
930fc45a CL |
505 | /** |
506 | * vmalloc_node - allocate memory on a specific node | |
507 | * | |
508 | * @size: allocation size | |
d44e0780 | 509 | * @node: numa node |
930fc45a CL |
510 | * |
511 | * Allocate enough pages to cover @size from the page level | |
512 | * allocator and map them into contiguous kernel virtual space. | |
513 | * | |
514 | * For tight cotrol over page level allocator and protection flags | |
515 | * use __vmalloc() instead. | |
516 | */ | |
517 | void *vmalloc_node(unsigned long size, int node) | |
518 | { | |
519 | return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL, node); | |
520 | } | |
521 | EXPORT_SYMBOL(vmalloc_node); | |
522 | ||
4dc3b16b PP |
523 | #ifndef PAGE_KERNEL_EXEC |
524 | # define PAGE_KERNEL_EXEC PAGE_KERNEL | |
525 | #endif | |
526 | ||
1da177e4 LT |
527 | /** |
528 | * vmalloc_exec - allocate virtually contiguous, executable memory | |
529 | * | |
530 | * @size: allocation size | |
531 | * | |
532 | * Kernel-internal function to allocate enough pages to cover @size | |
533 | * the page level allocator and map them into contiguous and | |
534 | * executable kernel virtual space. | |
535 | * | |
536 | * For tight cotrol over page level allocator and protection flags | |
537 | * use __vmalloc() instead. | |
538 | */ | |
539 | ||
1da177e4 LT |
540 | void *vmalloc_exec(unsigned long size) |
541 | { | |
542 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC); | |
543 | } | |
544 | ||
545 | /** | |
546 | * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) | |
547 | * | |
548 | * @size: allocation size | |
549 | * | |
550 | * Allocate enough 32bit PA addressable pages to cover @size from the | |
551 | * page level allocator and map them into contiguous kernel virtual space. | |
552 | */ | |
553 | void *vmalloc_32(unsigned long size) | |
554 | { | |
555 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); | |
556 | } | |
1da177e4 LT |
557 | EXPORT_SYMBOL(vmalloc_32); |
558 | ||
559 | long vread(char *buf, char *addr, unsigned long count) | |
560 | { | |
561 | struct vm_struct *tmp; | |
562 | char *vaddr, *buf_start = buf; | |
563 | unsigned long n; | |
564 | ||
565 | /* Don't allow overflow */ | |
566 | if ((unsigned long) addr + count < count) | |
567 | count = -(unsigned long) addr; | |
568 | ||
569 | read_lock(&vmlist_lock); | |
570 | for (tmp = vmlist; tmp; tmp = tmp->next) { | |
571 | vaddr = (char *) tmp->addr; | |
572 | if (addr >= vaddr + tmp->size - PAGE_SIZE) | |
573 | continue; | |
574 | while (addr < vaddr) { | |
575 | if (count == 0) | |
576 | goto finished; | |
577 | *buf = '\0'; | |
578 | buf++; | |
579 | addr++; | |
580 | count--; | |
581 | } | |
582 | n = vaddr + tmp->size - PAGE_SIZE - addr; | |
583 | do { | |
584 | if (count == 0) | |
585 | goto finished; | |
586 | *buf = *addr; | |
587 | buf++; | |
588 | addr++; | |
589 | count--; | |
590 | } while (--n > 0); | |
591 | } | |
592 | finished: | |
593 | read_unlock(&vmlist_lock); | |
594 | return buf - buf_start; | |
595 | } | |
596 | ||
597 | long vwrite(char *buf, char *addr, unsigned long count) | |
598 | { | |
599 | struct vm_struct *tmp; | |
600 | char *vaddr, *buf_start = buf; | |
601 | unsigned long n; | |
602 | ||
603 | /* Don't allow overflow */ | |
604 | if ((unsigned long) addr + count < count) | |
605 | count = -(unsigned long) addr; | |
606 | ||
607 | read_lock(&vmlist_lock); | |
608 | for (tmp = vmlist; tmp; tmp = tmp->next) { | |
609 | vaddr = (char *) tmp->addr; | |
610 | if (addr >= vaddr + tmp->size - PAGE_SIZE) | |
611 | continue; | |
612 | while (addr < vaddr) { | |
613 | if (count == 0) | |
614 | goto finished; | |
615 | buf++; | |
616 | addr++; | |
617 | count--; | |
618 | } | |
619 | n = vaddr + tmp->size - PAGE_SIZE - addr; | |
620 | do { | |
621 | if (count == 0) | |
622 | goto finished; | |
623 | *addr = *buf; | |
624 | buf++; | |
625 | addr++; | |
626 | count--; | |
627 | } while (--n > 0); | |
628 | } | |
629 | finished: | |
630 | read_unlock(&vmlist_lock); | |
631 | return buf - buf_start; | |
632 | } |