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 buffer_head * create_bounce(int rw, struct buffer_head * bh_orig);
  17
  18
  19 static inline char *bh_kmap(struct buffer_head *bh)
  20 {
  21         return kmap(bh->b_page) + bh_offset(bh);
  22 }
  23
  24 static inline void bh_kunmap(struct buffer_head *bh)
  25 {
  26         kunmap(bh->b_page);
  27 }
  28
  29 #else /* CONFIG_HIGHMEM */
  30
  31 static inline unsigned int nr_free_highpages(void) { return 0; }
  32
  33 static inline void *kmap(struct page *page) { return page_address(page); }
  34
  35 #define kunmap(page) do { } while (0)
  36
  37 #define kmap_atomic(page,idx)           kmap(page)
  38 #define kunmap_atomic(page,idx)         kunmap(page)
  39
  40 #define bh_kmap(bh)     ((bh)->b_data)
  41 #define bh_kunmap(bh)   do { } while (0);
  42
  43 #endif /* CONFIG_HIGHMEM */
  44
  45 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  46 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  47 {
  48         clear_user_page(kmap(page), vaddr);
  49         kunmap(page);
  50 }
  51
  52 static inline void clear_highpage(struct page *page)
  53 {
  54         clear_page(kmap(page));
  55         kunmap(page);
  56 }
  57
  58 static inline void memclear_highpage(struct page *page, unsigned int offset, unsigned int size)
  59 {
  60         char *kaddr;
  61
  62         if (offset + size > PAGE_SIZE)
  63                 BUG();
  64         kaddr = kmap(page);
  65         memset(kaddr + offset, 0, size);
  66         kunmap(page);
  67 }
  68
  69 /*
  70  * Same but also flushes aliased cache contents to RAM.
  71  */
  72 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
  73 {
  74         char *kaddr;
  75
  76         if (offset + size > PAGE_SIZE)
  77                 BUG();
  78         kaddr = kmap(page);
  79         memset(kaddr + offset, 0, size);
  80         flush_page_to_ram(page);
  81         kunmap(page);
  82 }
  83
  84 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
  85 {
  86         char *vfrom, *vto;
  87
  88         vfrom = kmap(from);
  89         vto = kmap(to);
  90         copy_user_page(vto, vfrom, vaddr);
  91         kunmap(from);
  92         kunmap(to);
  93 }
  94
  95 static inline void copy_highpage(struct page *to, struct page *from)
  96 {
  97         char *vfrom, *vto;
  98
  99         vfrom = kmap(from);
 100         vto = kmap(to);
 101         copy_page(vto, vfrom);
 102         kunmap(from);
 103         kunmap(to);
 104 }
 105
 106 #endif /* _LINUX_HIGHMEM_H */