mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-30 07:34:12 +08:00
20c8ccb197
Based on 1 normalized pattern(s): this work is licensed under the terms of the gnu gpl version 2 see the copying file in the top level directory extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 35 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
99 lines
2.5 KiB
C
99 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (c) 2013
|
|
* Phillip Lougher <phillip@squashfs.org.uk>
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/pagemap.h>
|
|
#include "page_actor.h"
|
|
|
|
/*
|
|
* This file contains implementations of page_actor for decompressing into
|
|
* an intermediate buffer, and for decompressing directly into the
|
|
* page cache.
|
|
*
|
|
* Calling code should avoid sleeping between calls to squashfs_first_page()
|
|
* and squashfs_finish_page().
|
|
*/
|
|
|
|
/* Implementation of page_actor for decompressing into intermediate buffer */
|
|
static void *cache_first_page(struct squashfs_page_actor *actor)
|
|
{
|
|
actor->next_page = 1;
|
|
return actor->buffer[0];
|
|
}
|
|
|
|
static void *cache_next_page(struct squashfs_page_actor *actor)
|
|
{
|
|
if (actor->next_page == actor->pages)
|
|
return NULL;
|
|
|
|
return actor->buffer[actor->next_page++];
|
|
}
|
|
|
|
static void cache_finish_page(struct squashfs_page_actor *actor)
|
|
{
|
|
/* empty */
|
|
}
|
|
|
|
struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
|
|
int pages, int length)
|
|
{
|
|
struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
|
|
|
|
if (actor == NULL)
|
|
return NULL;
|
|
|
|
actor->length = length ? : pages * PAGE_SIZE;
|
|
actor->buffer = buffer;
|
|
actor->pages = pages;
|
|
actor->next_page = 0;
|
|
actor->squashfs_first_page = cache_first_page;
|
|
actor->squashfs_next_page = cache_next_page;
|
|
actor->squashfs_finish_page = cache_finish_page;
|
|
return actor;
|
|
}
|
|
|
|
/* Implementation of page_actor for decompressing directly into page cache. */
|
|
static void *direct_first_page(struct squashfs_page_actor *actor)
|
|
{
|
|
actor->next_page = 1;
|
|
return actor->pageaddr = kmap_atomic(actor->page[0]);
|
|
}
|
|
|
|
static void *direct_next_page(struct squashfs_page_actor *actor)
|
|
{
|
|
if (actor->pageaddr)
|
|
kunmap_atomic(actor->pageaddr);
|
|
|
|
return actor->pageaddr = actor->next_page == actor->pages ? NULL :
|
|
kmap_atomic(actor->page[actor->next_page++]);
|
|
}
|
|
|
|
static void direct_finish_page(struct squashfs_page_actor *actor)
|
|
{
|
|
if (actor->pageaddr)
|
|
kunmap_atomic(actor->pageaddr);
|
|
}
|
|
|
|
struct squashfs_page_actor *squashfs_page_actor_init_special(struct page **page,
|
|
int pages, int length)
|
|
{
|
|
struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
|
|
|
|
if (actor == NULL)
|
|
return NULL;
|
|
|
|
actor->length = length ? : pages * PAGE_SIZE;
|
|
actor->page = page;
|
|
actor->pages = pages;
|
|
actor->next_page = 0;
|
|
actor->pageaddr = NULL;
|
|
actor->squashfs_first_page = direct_first_page;
|
|
actor->squashfs_next_page = direct_next_page;
|
|
actor->squashfs_finish_page = direct_finish_page;
|
|
return actor;
|
|
}
|