fs/squashfs/page_actor.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 #ifndef PAGE_ACTOR_H
   3 #define PAGE_ACTOR_H
   4 /*
   5  * Copyright (c) 2013
   6  * Phillip Lougher <phillip@squashfs.org.uk>
   7  */
   8
   9 #ifndef CONFIG_SQUASHFS_FILE_DIRECT
  10 struct squashfs_page_actor {
  11         void    **page;
  12         int     pages;
  13         int     length;
  14         int     next_page;
  15 };
  16
  17 static inline struct squashfs_page_actor *squashfs_page_actor_init(void **page,
  18         int pages, int length)
  19 {
  20         struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
  21
  22         if (actor == NULL)
  23                 return NULL;
  24
  25         actor->length = length ? : pages * PAGE_SIZE;
  26         actor->page = page;
  27         actor->pages = pages;
  28         actor->next_page = 0;
  29         return actor;
  30 }
  31
  32 static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
  33 {
  34         actor->next_page = 1;
  35         return actor->page[0];
  36 }
  37
  38 static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
  39 {
  40         return actor->next_page == actor->pages ? NULL :
  41                 actor->page[actor->next_page++];
  42 }
  43
  44 static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
  45 {
  46         /* empty */
  47 }
  48 #else
  49 struct squashfs_page_actor {
  50         union {
  51                 void            **buffer;
  52                 struct page     **page;
  53         };
  54         void    *pageaddr;
  55         void    *(*squashfs_first_page)(struct squashfs_page_actor *);
  56         void    *(*squashfs_next_page)(struct squashfs_page_actor *);
  57         void    (*squashfs_finish_page)(struct squashfs_page_actor *);
  58         int     pages;
  59         int     length;
  60         int     next_page;
  61 };
  62
  63 extern struct squashfs_page_actor *squashfs_page_actor_init(void **, int, int);
  64 extern struct squashfs_page_actor *squashfs_page_actor_init_special(struct page
  65                                                          **, int, int);
  66 static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
  67 {
  68         return actor->squashfs_first_page(actor);
  69 }
  70 static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
  71 {
  72         return actor->squashfs_next_page(actor);
  73 }
  74 static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
  75 {
  76         actor->squashfs_finish_page(actor);
  77 }
  78 #endif
  79 #endif