fs/squashfs/page_actor.h

   1 #ifndef PAGE_ACTOR_H
   2 #define PAGE_ACTOR_H
   3 /*
   4  * Copyright (c) 2013
   5  * Phillip Lougher <phillip@squashfs.org.uk>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2. See
   8  * the COPYING file in the top-level directory.
   9  */
  10
  11 #ifndef CONFIG_SQUASHFS_FILE_DIRECT
  12 struct squashfs_page_actor {
  13         void    **page;
  14         int     pages;
  15         int     length;
  16         int     next_page;
  17 };
  18
  19 static inline struct squashfs_page_actor *squashfs_page_actor_init(void **page,
  20         int pages, int length)
  21 {
  22         struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
  23
  24         if (actor == NULL)
  25                 return NULL;
  26
  27         actor->length = length ? : pages * PAGE_CACHE_SIZE;
  28         actor->page = page;
  29         actor->pages = pages;
  30         actor->next_page = 0;
  31         return actor;
  32 }
  33
  34 static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
  35 {
  36         actor->next_page = 1;
  37         return actor->page[0];
  38 }
  39
  40 static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
  41 {
  42         return actor->next_page == actor->pages ? NULL :
  43                 actor->page[actor->next_page++];
  44 }
  45
  46 static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
  47 {
  48         /* empty */
  49 }
  50 #else
  51 struct squashfs_page_actor {
  52         union {
  53                 void            **buffer;
  54                 struct page     **page;
  55         };
  56         void    *pageaddr;
  57         void    *(*squashfs_first_page)(struct squashfs_page_actor *);
  58         void    *(*squashfs_next_page)(struct squashfs_page_actor *);
  59         void    (*squashfs_finish_page)(struct squashfs_page_actor *);
  60         int     pages;
  61         int     length;
  62         int     next_page;
  63 };
  64
  65 extern struct squashfs_page_actor *squashfs_page_actor_init(void **, int, int);
  66 extern struct squashfs_page_actor *squashfs_page_actor_init_special(struct page
  67                                                          **, int, int);
  68 static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
  69 {
  70         return actor->squashfs_first_page(actor);
  71 }
  72 static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
  73 {
  74         return actor->squashfs_next_page(actor);
  75 }
  76 static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
  77 {
  78         actor->squashfs_finish_page(actor);
  79 }
  80 #endif
  81 #endif