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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * High memory handling common code and variables. | |
3 | * | |
4 | * (C) 1999 Andrea Arcangeli, SuSE GmbH, andrea@suse.de | |
5 | * Gerhard Wichert, Siemens AG, Gerhard.Wichert@pdb.siemens.de | |
6 | * | |
7 | * | |
8 | * Redesigned the x86 32-bit VM architecture to deal with | |
9 | * 64-bit physical space. With current x86 CPUs this | |
10 | * means up to 64 Gigabytes physical RAM. | |
11 | * | |
12 | * Rewrote high memory support to move the page cache into | |
13 | * high memory. Implemented permanent (schedulable) kmaps | |
14 | * based on Linus' idea. | |
15 | * | |
16 | * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> | |
17 | */ | |
18 | ||
19 | #include <linux/mm.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/swap.h> | |
22 | #include <linux/bio.h> | |
23 | #include <linux/pagemap.h> | |
24 | #include <linux/mempool.h> | |
25 | #include <linux/blkdev.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/hash.h> | |
28 | #include <linux/highmem.h> | |
2056a782 | 29 | #include <linux/blktrace_api.h> |
1da177e4 LT |
30 | #include <asm/tlbflush.h> |
31 | ||
32 | static mempool_t *page_pool, *isa_page_pool; | |
33 | ||
a19b27ce | 34 | static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data) |
1da177e4 | 35 | { |
a19b27ce | 36 | return mempool_alloc_pages(gfp_mask | GFP_DMA, data); |
1da177e4 LT |
37 | } |
38 | ||
39 | /* | |
40 | * Virtual_count is not a pure "count". | |
41 | * 0 means that it is not mapped, and has not been mapped | |
42 | * since a TLB flush - it is usable. | |
43 | * 1 means that there are no users, but it has been mapped | |
44 | * since the last TLB flush - so we can't use it. | |
45 | * n means that there are (n-1) current users of it. | |
46 | */ | |
47 | #ifdef CONFIG_HIGHMEM | |
260b2367 | 48 | |
1da177e4 LT |
49 | static int pkmap_count[LAST_PKMAP]; |
50 | static unsigned int last_pkmap_nr; | |
51 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock); | |
52 | ||
53 | pte_t * pkmap_page_table; | |
54 | ||
55 | static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait); | |
56 | ||
57 | static void flush_all_zero_pkmaps(void) | |
58 | { | |
59 | int i; | |
60 | ||
61 | flush_cache_kmaps(); | |
62 | ||
63 | for (i = 0; i < LAST_PKMAP; i++) { | |
64 | struct page *page; | |
65 | ||
66 | /* | |
67 | * zero means we don't have anything to do, | |
68 | * >1 means that it is still in use. Only | |
69 | * a count of 1 means that it is free but | |
70 | * needs to be unmapped | |
71 | */ | |
72 | if (pkmap_count[i] != 1) | |
73 | continue; | |
74 | pkmap_count[i] = 0; | |
75 | ||
76 | /* sanity check */ | |
77 | if (pte_none(pkmap_page_table[i])) | |
78 | BUG(); | |
79 | ||
80 | /* | |
81 | * Don't need an atomic fetch-and-clear op here; | |
82 | * no-one has the page mapped, and cannot get at | |
83 | * its virtual address (and hence PTE) without first | |
84 | * getting the kmap_lock (which is held here). | |
85 | * So no dangers, even with speculative execution. | |
86 | */ | |
87 | page = pte_page(pkmap_page_table[i]); | |
88 | pte_clear(&init_mm, (unsigned long)page_address(page), | |
89 | &pkmap_page_table[i]); | |
90 | ||
91 | set_page_address(page, NULL); | |
92 | } | |
93 | flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP)); | |
94 | } | |
95 | ||
96 | static inline unsigned long map_new_virtual(struct page *page) | |
97 | { | |
98 | unsigned long vaddr; | |
99 | int count; | |
100 | ||
101 | start: | |
102 | count = LAST_PKMAP; | |
103 | /* Find an empty entry */ | |
104 | for (;;) { | |
105 | last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK; | |
106 | if (!last_pkmap_nr) { | |
107 | flush_all_zero_pkmaps(); | |
108 | count = LAST_PKMAP; | |
109 | } | |
110 | if (!pkmap_count[last_pkmap_nr]) | |
111 | break; /* Found a usable entry */ | |
112 | if (--count) | |
113 | continue; | |
114 | ||
115 | /* | |
116 | * Sleep for somebody else to unmap their entries | |
117 | */ | |
118 | { | |
119 | DECLARE_WAITQUEUE(wait, current); | |
120 | ||
121 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
122 | add_wait_queue(&pkmap_map_wait, &wait); | |
123 | spin_unlock(&kmap_lock); | |
124 | schedule(); | |
125 | remove_wait_queue(&pkmap_map_wait, &wait); | |
126 | spin_lock(&kmap_lock); | |
127 | ||
128 | /* Somebody else might have mapped it while we slept */ | |
129 | if (page_address(page)) | |
130 | return (unsigned long)page_address(page); | |
131 | ||
132 | /* Re-start */ | |
133 | goto start; | |
134 | } | |
135 | } | |
136 | vaddr = PKMAP_ADDR(last_pkmap_nr); | |
137 | set_pte_at(&init_mm, vaddr, | |
138 | &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot)); | |
139 | ||
140 | pkmap_count[last_pkmap_nr] = 1; | |
141 | set_page_address(page, (void *)vaddr); | |
142 | ||
143 | return vaddr; | |
144 | } | |
145 | ||
146 | void fastcall *kmap_high(struct page *page) | |
147 | { | |
148 | unsigned long vaddr; | |
149 | ||
150 | /* | |
151 | * For highmem pages, we can't trust "virtual" until | |
152 | * after we have the lock. | |
153 | * | |
154 | * We cannot call this from interrupts, as it may block | |
155 | */ | |
156 | spin_lock(&kmap_lock); | |
157 | vaddr = (unsigned long)page_address(page); | |
158 | if (!vaddr) | |
159 | vaddr = map_new_virtual(page); | |
160 | pkmap_count[PKMAP_NR(vaddr)]++; | |
161 | if (pkmap_count[PKMAP_NR(vaddr)] < 2) | |
162 | BUG(); | |
163 | spin_unlock(&kmap_lock); | |
164 | return (void*) vaddr; | |
165 | } | |
166 | ||
167 | EXPORT_SYMBOL(kmap_high); | |
168 | ||
169 | void fastcall kunmap_high(struct page *page) | |
170 | { | |
171 | unsigned long vaddr; | |
172 | unsigned long nr; | |
173 | int need_wakeup; | |
174 | ||
175 | spin_lock(&kmap_lock); | |
176 | vaddr = (unsigned long)page_address(page); | |
177 | if (!vaddr) | |
178 | BUG(); | |
179 | nr = PKMAP_NR(vaddr); | |
180 | ||
181 | /* | |
182 | * A count must never go down to zero | |
183 | * without a TLB flush! | |
184 | */ | |
185 | need_wakeup = 0; | |
186 | switch (--pkmap_count[nr]) { | |
187 | case 0: | |
188 | BUG(); | |
189 | case 1: | |
190 | /* | |
191 | * Avoid an unnecessary wake_up() function call. | |
192 | * The common case is pkmap_count[] == 1, but | |
193 | * no waiters. | |
194 | * The tasks queued in the wait-queue are guarded | |
195 | * by both the lock in the wait-queue-head and by | |
196 | * the kmap_lock. As the kmap_lock is held here, | |
197 | * no need for the wait-queue-head's lock. Simply | |
198 | * test if the queue is empty. | |
199 | */ | |
200 | need_wakeup = waitqueue_active(&pkmap_map_wait); | |
201 | } | |
202 | spin_unlock(&kmap_lock); | |
203 | ||
204 | /* do wake-up, if needed, race-free outside of the spin lock */ | |
205 | if (need_wakeup) | |
206 | wake_up(&pkmap_map_wait); | |
207 | } | |
208 | ||
209 | EXPORT_SYMBOL(kunmap_high); | |
210 | ||
211 | #define POOL_SIZE 64 | |
212 | ||
213 | static __init int init_emergency_pool(void) | |
214 | { | |
215 | struct sysinfo i; | |
216 | si_meminfo(&i); | |
217 | si_swapinfo(&i); | |
218 | ||
219 | if (!i.totalhigh) | |
220 | return 0; | |
221 | ||
a19b27ce | 222 | page_pool = mempool_create_page_pool(POOL_SIZE, 0); |
1da177e4 LT |
223 | if (!page_pool) |
224 | BUG(); | |
225 | printk("highmem bounce pool size: %d pages\n", POOL_SIZE); | |
226 | ||
227 | return 0; | |
228 | } | |
229 | ||
230 | __initcall(init_emergency_pool); | |
231 | ||
232 | /* | |
233 | * highmem version, map in to vec | |
234 | */ | |
235 | static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom) | |
236 | { | |
237 | unsigned long flags; | |
238 | unsigned char *vto; | |
239 | ||
240 | local_irq_save(flags); | |
241 | vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ); | |
242 | memcpy(vto + to->bv_offset, vfrom, to->bv_len); | |
243 | kunmap_atomic(vto, KM_BOUNCE_READ); | |
244 | local_irq_restore(flags); | |
245 | } | |
246 | ||
247 | #else /* CONFIG_HIGHMEM */ | |
248 | ||
249 | #define bounce_copy_vec(to, vfrom) \ | |
250 | memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len) | |
251 | ||
252 | #endif | |
253 | ||
254 | #define ISA_POOL_SIZE 16 | |
255 | ||
256 | /* | |
257 | * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA | |
258 | * as the max address, so check if the pool has already been created. | |
259 | */ | |
260 | int init_emergency_isa_pool(void) | |
261 | { | |
262 | if (isa_page_pool) | |
263 | return 0; | |
264 | ||
a19b27ce MD |
265 | isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa, |
266 | mempool_free_pages, (void *) 0); | |
1da177e4 LT |
267 | if (!isa_page_pool) |
268 | BUG(); | |
269 | ||
270 | printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE); | |
271 | return 0; | |
272 | } | |
273 | ||
274 | /* | |
275 | * Simple bounce buffer support for highmem pages. Depending on the | |
276 | * queue gfp mask set, *to may or may not be a highmem page. kmap it | |
277 | * always, it will do the Right Thing | |
278 | */ | |
279 | static void copy_to_high_bio_irq(struct bio *to, struct bio *from) | |
280 | { | |
281 | unsigned char *vfrom; | |
282 | struct bio_vec *tovec, *fromvec; | |
283 | int i; | |
284 | ||
285 | __bio_for_each_segment(tovec, to, i, 0) { | |
286 | fromvec = from->bi_io_vec + i; | |
287 | ||
288 | /* | |
289 | * not bounced | |
290 | */ | |
291 | if (tovec->bv_page == fromvec->bv_page) | |
292 | continue; | |
293 | ||
294 | /* | |
295 | * fromvec->bv_offset and fromvec->bv_len might have been | |
296 | * modified by the block layer, so use the original copy, | |
297 | * bounce_copy_vec already uses tovec->bv_len | |
298 | */ | |
299 | vfrom = page_address(fromvec->bv_page) + tovec->bv_offset; | |
300 | ||
301 | flush_dcache_page(tovec->bv_page); | |
302 | bounce_copy_vec(tovec, vfrom); | |
303 | } | |
304 | } | |
305 | ||
306 | static void bounce_end_io(struct bio *bio, mempool_t *pool, int err) | |
307 | { | |
308 | struct bio *bio_orig = bio->bi_private; | |
309 | struct bio_vec *bvec, *org_vec; | |
310 | int i; | |
311 | ||
312 | if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags)) | |
313 | set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags); | |
314 | ||
315 | /* | |
316 | * free up bounce indirect pages used | |
317 | */ | |
318 | __bio_for_each_segment(bvec, bio, i, 0) { | |
319 | org_vec = bio_orig->bi_io_vec + i; | |
320 | if (bvec->bv_page == org_vec->bv_page) | |
321 | continue; | |
322 | ||
323 | mempool_free(bvec->bv_page, pool); | |
edfbe2b0 | 324 | dec_page_state(nr_bounce); |
1da177e4 LT |
325 | } |
326 | ||
327 | bio_endio(bio_orig, bio_orig->bi_size, err); | |
328 | bio_put(bio); | |
329 | } | |
330 | ||
a19b27ce | 331 | static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done, int err) |
1da177e4 LT |
332 | { |
333 | if (bio->bi_size) | |
334 | return 1; | |
335 | ||
336 | bounce_end_io(bio, page_pool, err); | |
337 | return 0; | |
338 | } | |
339 | ||
340 | static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int err) | |
341 | { | |
342 | if (bio->bi_size) | |
343 | return 1; | |
344 | ||
345 | bounce_end_io(bio, isa_page_pool, err); | |
346 | return 0; | |
347 | } | |
348 | ||
349 | static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err) | |
350 | { | |
351 | struct bio *bio_orig = bio->bi_private; | |
352 | ||
353 | if (test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
354 | copy_to_high_bio_irq(bio_orig, bio); | |
355 | ||
356 | bounce_end_io(bio, pool, err); | |
357 | } | |
358 | ||
359 | static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err) | |
360 | { | |
361 | if (bio->bi_size) | |
362 | return 1; | |
363 | ||
364 | __bounce_end_io_read(bio, page_pool, err); | |
365 | return 0; | |
366 | } | |
367 | ||
368 | static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int err) | |
369 | { | |
370 | if (bio->bi_size) | |
371 | return 1; | |
372 | ||
373 | __bounce_end_io_read(bio, isa_page_pool, err); | |
374 | return 0; | |
375 | } | |
376 | ||
377 | static void __blk_queue_bounce(request_queue_t *q, struct bio **bio_orig, | |
a19b27ce | 378 | mempool_t *pool) |
1da177e4 LT |
379 | { |
380 | struct page *page; | |
381 | struct bio *bio = NULL; | |
382 | int i, rw = bio_data_dir(*bio_orig); | |
383 | struct bio_vec *to, *from; | |
384 | ||
385 | bio_for_each_segment(from, *bio_orig, i) { | |
386 | page = from->bv_page; | |
387 | ||
388 | /* | |
389 | * is destination page below bounce pfn? | |
390 | */ | |
391 | if (page_to_pfn(page) < q->bounce_pfn) | |
392 | continue; | |
393 | ||
394 | /* | |
395 | * irk, bounce it | |
396 | */ | |
397 | if (!bio) | |
398 | bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt); | |
399 | ||
400 | to = bio->bi_io_vec + i; | |
401 | ||
402 | to->bv_page = mempool_alloc(pool, q->bounce_gfp); | |
403 | to->bv_len = from->bv_len; | |
404 | to->bv_offset = from->bv_offset; | |
edfbe2b0 | 405 | inc_page_state(nr_bounce); |
1da177e4 LT |
406 | |
407 | if (rw == WRITE) { | |
408 | char *vto, *vfrom; | |
409 | ||
410 | flush_dcache_page(from->bv_page); | |
411 | vto = page_address(to->bv_page) + to->bv_offset; | |
412 | vfrom = kmap(from->bv_page) + from->bv_offset; | |
413 | memcpy(vto, vfrom, to->bv_len); | |
414 | kunmap(from->bv_page); | |
415 | } | |
416 | } | |
417 | ||
418 | /* | |
419 | * no pages bounced | |
420 | */ | |
421 | if (!bio) | |
422 | return; | |
423 | ||
424 | /* | |
425 | * at least one page was bounced, fill in possible non-highmem | |
426 | * pages | |
427 | */ | |
428 | __bio_for_each_segment(from, *bio_orig, i, 0) { | |
429 | to = bio_iovec_idx(bio, i); | |
430 | if (!to->bv_page) { | |
431 | to->bv_page = from->bv_page; | |
432 | to->bv_len = from->bv_len; | |
433 | to->bv_offset = from->bv_offset; | |
434 | } | |
435 | } | |
436 | ||
437 | bio->bi_bdev = (*bio_orig)->bi_bdev; | |
438 | bio->bi_flags |= (1 << BIO_BOUNCED); | |
439 | bio->bi_sector = (*bio_orig)->bi_sector; | |
440 | bio->bi_rw = (*bio_orig)->bi_rw; | |
441 | ||
442 | bio->bi_vcnt = (*bio_orig)->bi_vcnt; | |
443 | bio->bi_idx = (*bio_orig)->bi_idx; | |
444 | bio->bi_size = (*bio_orig)->bi_size; | |
445 | ||
446 | if (pool == page_pool) { | |
447 | bio->bi_end_io = bounce_end_io_write; | |
448 | if (rw == READ) | |
449 | bio->bi_end_io = bounce_end_io_read; | |
450 | } else { | |
451 | bio->bi_end_io = bounce_end_io_write_isa; | |
452 | if (rw == READ) | |
453 | bio->bi_end_io = bounce_end_io_read_isa; | |
454 | } | |
455 | ||
456 | bio->bi_private = *bio_orig; | |
457 | *bio_orig = bio; | |
458 | } | |
459 | ||
460 | void blk_queue_bounce(request_queue_t *q, struct bio **bio_orig) | |
461 | { | |
462 | mempool_t *pool; | |
463 | ||
464 | /* | |
465 | * for non-isa bounce case, just check if the bounce pfn is equal | |
466 | * to or bigger than the highest pfn in the system -- in that case, | |
467 | * don't waste time iterating over bio segments | |
468 | */ | |
469 | if (!(q->bounce_gfp & GFP_DMA)) { | |
470 | if (q->bounce_pfn >= blk_max_pfn) | |
471 | return; | |
472 | pool = page_pool; | |
473 | } else { | |
474 | BUG_ON(!isa_page_pool); | |
475 | pool = isa_page_pool; | |
476 | } | |
477 | ||
2056a782 JA |
478 | blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE); |
479 | ||
1da177e4 LT |
480 | /* |
481 | * slow path | |
482 | */ | |
483 | __blk_queue_bounce(q, bio_orig, pool); | |
484 | } | |
485 | ||
486 | EXPORT_SYMBOL(blk_queue_bounce); | |
487 | ||
488 | #if defined(HASHED_PAGE_VIRTUAL) | |
489 | ||
490 | #define PA_HASH_ORDER 7 | |
491 | ||
492 | /* | |
493 | * Describes one page->virtual association | |
494 | */ | |
495 | struct page_address_map { | |
496 | struct page *page; | |
497 | void *virtual; | |
498 | struct list_head list; | |
499 | }; | |
500 | ||
501 | /* | |
502 | * page_address_map freelist, allocated from page_address_maps. | |
503 | */ | |
504 | static struct list_head page_address_pool; /* freelist */ | |
505 | static spinlock_t pool_lock; /* protects page_address_pool */ | |
506 | ||
507 | /* | |
508 | * Hash table bucket | |
509 | */ | |
510 | static struct page_address_slot { | |
511 | struct list_head lh; /* List of page_address_maps */ | |
512 | spinlock_t lock; /* Protect this bucket's list */ | |
513 | } ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER]; | |
514 | ||
515 | static struct page_address_slot *page_slot(struct page *page) | |
516 | { | |
517 | return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)]; | |
518 | } | |
519 | ||
520 | void *page_address(struct page *page) | |
521 | { | |
522 | unsigned long flags; | |
523 | void *ret; | |
524 | struct page_address_slot *pas; | |
525 | ||
526 | if (!PageHighMem(page)) | |
527 | return lowmem_page_address(page); | |
528 | ||
529 | pas = page_slot(page); | |
530 | ret = NULL; | |
531 | spin_lock_irqsave(&pas->lock, flags); | |
532 | if (!list_empty(&pas->lh)) { | |
533 | struct page_address_map *pam; | |
534 | ||
535 | list_for_each_entry(pam, &pas->lh, list) { | |
536 | if (pam->page == page) { | |
537 | ret = pam->virtual; | |
538 | goto done; | |
539 | } | |
540 | } | |
541 | } | |
542 | done: | |
543 | spin_unlock_irqrestore(&pas->lock, flags); | |
544 | return ret; | |
545 | } | |
546 | ||
547 | EXPORT_SYMBOL(page_address); | |
548 | ||
549 | void set_page_address(struct page *page, void *virtual) | |
550 | { | |
551 | unsigned long flags; | |
552 | struct page_address_slot *pas; | |
553 | struct page_address_map *pam; | |
554 | ||
555 | BUG_ON(!PageHighMem(page)); | |
556 | ||
557 | pas = page_slot(page); | |
558 | if (virtual) { /* Add */ | |
559 | BUG_ON(list_empty(&page_address_pool)); | |
560 | ||
561 | spin_lock_irqsave(&pool_lock, flags); | |
562 | pam = list_entry(page_address_pool.next, | |
563 | struct page_address_map, list); | |
564 | list_del(&pam->list); | |
565 | spin_unlock_irqrestore(&pool_lock, flags); | |
566 | ||
567 | pam->page = page; | |
568 | pam->virtual = virtual; | |
569 | ||
570 | spin_lock_irqsave(&pas->lock, flags); | |
571 | list_add_tail(&pam->list, &pas->lh); | |
572 | spin_unlock_irqrestore(&pas->lock, flags); | |
573 | } else { /* Remove */ | |
574 | spin_lock_irqsave(&pas->lock, flags); | |
575 | list_for_each_entry(pam, &pas->lh, list) { | |
576 | if (pam->page == page) { | |
577 | list_del(&pam->list); | |
578 | spin_unlock_irqrestore(&pas->lock, flags); | |
579 | spin_lock_irqsave(&pool_lock, flags); | |
580 | list_add_tail(&pam->list, &page_address_pool); | |
581 | spin_unlock_irqrestore(&pool_lock, flags); | |
582 | goto done; | |
583 | } | |
584 | } | |
585 | spin_unlock_irqrestore(&pas->lock, flags); | |
586 | } | |
587 | done: | |
588 | return; | |
589 | } | |
590 | ||
591 | static struct page_address_map page_address_maps[LAST_PKMAP]; | |
592 | ||
593 | void __init page_address_init(void) | |
594 | { | |
595 | int i; | |
596 | ||
597 | INIT_LIST_HEAD(&page_address_pool); | |
598 | for (i = 0; i < ARRAY_SIZE(page_address_maps); i++) | |
599 | list_add(&page_address_maps[i].list, &page_address_pool); | |
600 | for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) { | |
601 | INIT_LIST_HEAD(&page_address_htable[i].lh); | |
602 | spin_lock_init(&page_address_htable[i].lock); | |
603 | } | |
604 | spin_lock_init(&pool_lock); | |
605 | } | |
606 | ||
607 | #endif /* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */ |