linux-old/include/linux/highmem.h
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   1#ifndef _LINUX_HIGHMEM_H
   2#define _LINUX_HIGHMEM_H
   3
   4#include <linux/config.h>
   5#include <asm/pgalloc.h>
   6
   7#ifdef CONFIG_HIGHMEM
   8
   9extern struct page *highmem_start_page;
  10
  11#include <asm/highmem.h>
  12
  13/* declarations for linux/mm/highmem.c */
  14unsigned int nr_free_highpages(void);
  15
  16extern struct buffer_head *create_bounce(int rw, struct buffer_head * bh_orig);
  17
  18static inline char *bh_kmap(struct buffer_head *bh)
  19{
  20        return kmap(bh->b_page) + bh_offset(bh);
  21}
  22
  23static inline void bh_kunmap(struct buffer_head *bh)
  24{
  25        kunmap(bh->b_page);
  26}
  27
  28/*
  29 * remember to add offset! and never ever reenable interrupts between a
  30 * bh_kmap_irq and bh_kunmap_irq!!
  31 */
  32static inline char *bh_kmap_irq(struct buffer_head *bh, unsigned long *flags)
  33{
  34        unsigned long addr;
  35
  36        __save_flags(*flags);
  37
  38        /*
  39         * could be low
  40         */
  41        if (!PageHighMem(bh->b_page))
  42                return bh->b_data;
  43
  44        /*
  45         * it's a highmem page
  46         */
  47        __cli();
  48        addr = (unsigned long) kmap_atomic(bh->b_page, KM_BH_IRQ);
  49
  50        if (addr & ~PAGE_MASK)
  51                BUG();
  52
  53        return (char *) addr + bh_offset(bh);
  54}
  55
  56static inline void bh_kunmap_irq(char *buffer, unsigned long *flags)
  57{
  58        unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
  59
  60        kunmap_atomic((void *) ptr, KM_BH_IRQ);
  61        __restore_flags(*flags);
  62}
  63
  64#else /* CONFIG_HIGHMEM */
  65
  66static inline unsigned int nr_free_highpages(void) { return 0; }
  67
  68static inline void *kmap(struct page *page) { return page_address(page); }
  69
  70#define kunmap(page) do { } while (0)
  71
  72#define kmap_atomic(page,idx)           kmap(page)
  73#define kunmap_atomic(page,idx)         kunmap(page)
  74
  75#define bh_kmap(bh)                     ((bh)->b_data)
  76#define bh_kunmap(bh)                   do { } while (0)
  77#define kmap_nonblock(page)            kmap(page)
  78#define bh_kmap_irq(bh, flags)          ((bh)->b_data)
  79#define bh_kunmap_irq(bh, flags)        do { *(flags) = 0; } while (0)
  80
  81#endif /* CONFIG_HIGHMEM */
  82
  83/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  84static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  85{
  86        void *addr = kmap_atomic(page, KM_USER0);
  87        clear_user_page(addr, vaddr);
  88        kunmap_atomic(addr, KM_USER0);
  89}
  90
  91static inline void clear_highpage(struct page *page)
  92{
  93        clear_page(kmap(page));
  94        kunmap(page);
  95}
  96
  97/*
  98 * Same but also flushes aliased cache contents to RAM.
  99 */
 100static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
 101{
 102        char *kaddr;
 103
 104        if (offset + size > PAGE_SIZE)
 105                out_of_line_bug();
 106        kaddr = kmap(page);
 107        memset(kaddr + offset, 0, size);
 108        flush_dcache_page(page);
 109        flush_page_to_ram(page);
 110        kunmap(page);
 111}
 112
 113static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
 114{
 115        char *vfrom, *vto;
 116
 117        vfrom = kmap_atomic(from, KM_USER0);
 118        vto = kmap_atomic(to, KM_USER1);
 119        copy_user_page(vto, vfrom, vaddr);
 120        kunmap_atomic(vfrom, KM_USER0);
 121        kunmap_atomic(vto, KM_USER1);
 122}
 123
 124static inline void copy_highpage(struct page *to, struct page *from)
 125{
 126        char *vfrom, *vto;
 127
 128        vfrom = kmap_atomic(from, KM_USER0);
 129        vto = kmap_atomic(to, KM_USER1);
 130        copy_page(vto, vfrom);
 131        kunmap_atomic(vfrom, KM_USER0);
 132        kunmap_atomic(vto, KM_USER1);
 133}
 134
 135#endif /* _LINUX_HIGHMEM_H */
 136
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