123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136 |
- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Copyright (c) 2013
- * Phillip Lougher <[email protected]>
- */
- #include <linux/kernel.h>
- #include <linux/slab.h>
- #include <linux/pagemap.h>
- #include "squashfs_fs_sb.h"
- #include "decompressor.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->tmp_buffer = NULL;
- 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 *handle_next_page(struct squashfs_page_actor *actor)
- {
- int max_pages = (actor->length + PAGE_SIZE - 1) >> PAGE_SHIFT;
- if (actor->returned_pages == max_pages)
- return NULL;
- if ((actor->next_page == actor->pages) ||
- (actor->next_index != actor->page[actor->next_page]->index)) {
- actor->next_index++;
- actor->returned_pages++;
- actor->last_page = NULL;
- return actor->alloc_buffer ? actor->tmp_buffer : ERR_PTR(-ENOMEM);
- }
- actor->next_index++;
- actor->returned_pages++;
- actor->last_page = actor->page[actor->next_page];
- return actor->pageaddr = kmap_local_page(actor->page[actor->next_page++]);
- }
- static void *direct_first_page(struct squashfs_page_actor *actor)
- {
- return handle_next_page(actor);
- }
- static void *direct_next_page(struct squashfs_page_actor *actor)
- {
- if (actor->pageaddr) {
- kunmap_local(actor->pageaddr);
- actor->pageaddr = NULL;
- }
- return handle_next_page(actor);
- }
- static void direct_finish_page(struct squashfs_page_actor *actor)
- {
- if (actor->pageaddr)
- kunmap_local(actor->pageaddr);
- }
- struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_info *msblk,
- struct page **page, int pages, int length)
- {
- struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
- if (actor == NULL)
- return NULL;
- if (msblk->decompressor->alloc_buffer) {
- actor->tmp_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (actor->tmp_buffer == NULL) {
- kfree(actor);
- return NULL;
- }
- } else
- actor->tmp_buffer = NULL;
- actor->length = length ? : pages * PAGE_SIZE;
- actor->page = page;
- actor->pages = pages;
- actor->next_page = 0;
- actor->returned_pages = 0;
- actor->next_index = page[0]->index & ~((1 << (msblk->block_log - PAGE_SHIFT)) - 1);
- actor->pageaddr = NULL;
- actor->last_page = NULL;
- actor->alloc_buffer = msblk->decompressor->alloc_buffer;
- actor->squashfs_first_page = direct_first_page;
- actor->squashfs_next_page = direct_next_page;
- actor->squashfs_finish_page = direct_finish_page;
- return actor;
- }
|