Viewing file:  highmem.h (1.92 KB) -rw-r--r--
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#ifndef _LINUX_HIGHMEM_H
#define _LINUX_HIGHMEM_H
#include <linux/config.h>
#include <asm/pgalloc.h>
#ifdef CONFIG_HIGHMEM
extern struct page *highmem_start_page;
#include <asm/highmem.h>
/* declarations for linux/mm/highmem.c */
unsigned int nr_free_highpages(void);
extern struct buffer_head * create_bounce(int rw, struct buffer_head * bh_orig);
static inline char *bh_kmap(struct buffer_head *bh)
{
return kmap(bh->b_page) + bh_offset(bh);
}
static inline void bh_kunmap(struct buffer_head *bh)
{
kunmap(bh->b_page);
}
#else /* CONFIG_HIGHMEM */
static inline unsigned int nr_free_highpages(void) { return 0; }
static inline void *kmap(struct page *page) { return page_address(page); }
#define kunmap(page) do { } while (0)
#define kmap_atomic(page,idx) kmap(page)
#define kunmap_atomic(page,idx) kunmap(page)
#define bh_kmap(bh) ((bh)->b_data)
#define bh_kunmap(bh) do { } while (0)
#endif /* CONFIG_HIGHMEM */
/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
{
void *addr = kmap_atomic(page, KM_USER0);
clear_user_page(addr, vaddr);
kunmap_atomic(addr, KM_USER0);
}
static inline void clear_highpage(struct page *page)
{
clear_page(kmap(page));
kunmap(page);
}
/*
* Same but also flushes aliased cache contents to RAM.
*/
static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
{
char *kaddr;
if (offset + size > PAGE_SIZE)
BUG();
kaddr = kmap(page);
memset(kaddr + offset, 0, size);
flush_dcache_page(page);
flush_page_to_ram(page);
kunmap(page);
}
static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
{
char *vfrom, *vto;
vfrom = kmap_atomic(from, KM_USER0);
vto = kmap_atomic(to, KM_USER1);
copy_user_page(vto, vfrom, vaddr);
kunmap_atomic(vfrom, KM_USER0);
kunmap_atomic(vto, KM_USER1);
}
#endif /* _LINUX_HIGHMEM_H */
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