include/linux/pagevec.h

   1 /*
   2  * include/linux/pagevec.h
   3  *
   4  * In many places it is efficient to batch an operation up against multiple
   5  * pages.  A pagevec is a multipage container which is used for that.
   6  */
   7
   8 #ifndef _LINUX_PAGEVEC_H
   9 #define _LINUX_PAGEVEC_H
  10
  11 /* 14 pointers + two long's align the pagevec structure to a power of two */
  12 #define PAGEVEC_SIZE    14
  13
  14 struct page;
  15 struct address_space;
  16
  17 struct pagevec {
  18         unsigned long nr;
  19         unsigned long cold;
  20         struct page *pages[PAGEVEC_SIZE];
  21 };
  22
  23 void __pagevec_release(struct pagevec *pvec);
  24 void __pagevec_lru_add(struct pagevec *pvec);
  25 unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
  26                 pgoff_t start, unsigned nr_pages);
  27 unsigned pagevec_lookup_tag(struct pagevec *pvec,
  28                 struct address_space *mapping, pgoff_t *index, int tag,
  29                 unsigned nr_pages);
  30
  31 static inline void pagevec_init(struct pagevec *pvec, int cold)
  32 {
  33         pvec->nr = 0;
  34         pvec->cold = cold;
  35 }
  36
  37 static inline void pagevec_reinit(struct pagevec *pvec)
  38 {
  39         pvec->nr = 0;
  40 }
  41
  42 static inline unsigned pagevec_count(struct pagevec *pvec)
  43 {
  44         return pvec->nr;
  45 }
  46
  47 static inline unsigned pagevec_space(struct pagevec *pvec)
  48 {
  49         return PAGEVEC_SIZE - pvec->nr;
  50 }
  51
  52 /*
  53  * Add a page to a pagevec.  Returns the number of slots still available.
  54  */
  55 static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page)
  56 {
  57         pvec->pages[pvec->nr++] = page;
  58         return pagevec_space(pvec);
  59 }
  60
  61 static inline void pagevec_release(struct pagevec *pvec)
  62 {
  63         if (pagevec_count(pvec))
  64                 __pagevec_release(pvec);
  65 }
  66
  67 #endif /* _LINUX_PAGEVEC_H */