Merge git://git.kvack.org/~bcrl/aio-next
[firefly-linux-kernel-4.4.55.git] / 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