include/linux/highmem.h

   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
   9 extern struct page *highmem_start_page;
  10
  11 #include <asm/highmem.h>
  12
  13 /* declarations for linux/mm/highmem.c */
  14 FASTCALL(unsigned int nr_free_highpages(void));
  15
  16 extern struct page * prepare_highmem_swapout(struct page *);
  17 extern struct page * replace_with_highmem(struct page *);
  18 extern struct buffer_head * create_bounce(int rw, struct buffer_head * bh_orig);
  19
  20 #else /* CONFIG_HIGHMEM */
  21
  22 extern inline unsigned int nr_free_highpages(void) { return 0; }
  23 #define prepare_highmem_swapout(page) page
  24 #define replace_with_highmem(page) page
  25
  26 static __inline__ unsigned long kmap(struct page * page) {
  27         return (unsigned long) page_address(page);
  28 }
  29
  30 #define kunmap(page) do { } while (0)
  31
  32 #define kmap_atomic(page,idx)           kmap(page)
  33 #define kunmap_atomic(page,idx)         kunmap(page)
  34
  35 #endif /* CONFIG_HIGHMEM */
  36
  37 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  38 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  39 {
  40         unsigned long kaddr;
  41
  42         kaddr = kmap(page);
  43         clear_user_page((void *)kaddr, vaddr);
  44         kunmap(page);
  45 }
  46
  47 static inline void clear_highpage(struct page *page)
  48 {
  49         unsigned long kaddr;
  50
  51         kaddr = kmap(page);
  52         clear_page((void *)kaddr);
  53         kunmap(page);
  54 }
  55
  56 static inline void memclear_highpage(struct page *page, unsigned int offset, unsigned int size)
  57 {
  58         unsigned long kaddr;
  59
  60         if (offset + size > PAGE_SIZE)
  61                 BUG();
  62         kaddr = kmap(page);
  63         memset((void *)(kaddr + offset), 0, size);
  64         kunmap(page);
  65 }
  66
  67 /*
  68  * Same but also flushes aliased cache contents to RAM.
  69  */
  70 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
  71 {
  72         unsigned long kaddr;
  73
  74         if (offset + size > PAGE_SIZE)
  75                 BUG();
  76         kaddr = kmap(page);
  77         memset((void *)(kaddr + offset), 0, size);
  78         flush_page_to_ram(page);
  79         kunmap(page);
  80 }
  81
  82 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
  83 {
  84         unsigned long vfrom, vto;
  85
  86         vfrom = kmap(from);
  87         vto = kmap(to);
  88         copy_user_page((void *)vto, (void *)vfrom, vaddr);
  89         kunmap(from);
  90         kunmap(to);
  91 }
  92
  93 static inline void copy_highpage(struct page *to, struct page *from)
  94 {
  95         unsigned long vfrom, vto;
  96
  97         vfrom = kmap(from);
  98         vto = kmap(to);
  99         copy_page((void *)vto, (void *)vfrom);
 100         kunmap(from);
 101         kunmap(to);
 102 }
 103
 104 #endif /* _LINUX_HIGHMEM_H */