page_actor.h
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#ifndef PAGE_ACTOR_H
#define PAGE_ACTOR_H
/*
* Copyright (c) 2013
* Phillip Lougher <phillip@squashfs.org.uk>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level squashfsory.
*/
struct squashfs_page_actor {
struct page **page;
void *pageaddr;
int pages;
int length;
int next_page;
void (*release_pages)(struct page **, int, int);
};
extern struct squashfs_page_actor *squashfs_page_actor_init(struct page **,
int, int, void (*)(struct page **, int, int));
extern void squashfs_page_actor_free(struct squashfs_page_actor *, int);
extern void squashfs_actor_to_buf(struct squashfs_page_actor *, void *, int);
extern void squashfs_buf_to_actor(void *, struct squashfs_page_actor *, int);
extern void squashfs_bh_to_actor(struct buffer_head **, int,
struct squashfs_page_actor *, int, int, int);
extern void squashfs_bh_to_buf(struct buffer_head **, int, void *, int, int,
int);
/*
* Calling code should avoid sleeping between calls to squashfs_first_page()
* and squashfs_finish_page().
*/
static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
{
actor->next_page = 1;
return actor->pageaddr = actor->page[0] ? kmap_atomic(actor->page[0])
: NULL;
}
static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
{
if (!IS_ERR_OR_NULL(actor->pageaddr))
kunmap_atomic(actor->pageaddr);
if (actor->next_page == actor->pages)
return actor->pageaddr = ERR_PTR(-ENODATA);
actor->pageaddr = actor->page[actor->next_page] ?
kmap_atomic(actor->page[actor->next_page]) : NULL;
++actor->next_page;
return actor->pageaddr;
}
static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
{
if (!IS_ERR_OR_NULL(actor->pageaddr))
kunmap_atomic(actor->pageaddr);
}
extern struct page **alloc_page_array(int, int);
extern void free_page_array(struct page **, int);
#endif