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197 lines
4.5 KiB
197 lines
4.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (c) 2013 |
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* Minchan Kim <[email protected]> |
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*/ |
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#include <linux/types.h> |
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#include <linux/mutex.h> |
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#include <linux/slab.h> |
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#include <linux/bio.h> |
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#include <linux/sched.h> |
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#include <linux/wait.h> |
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#include <linux/cpumask.h> |
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#include "squashfs_fs.h" |
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#include "squashfs_fs_sb.h" |
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#include "decompressor.h" |
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#include "squashfs.h" |
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/* |
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* This file implements multi-threaded decompression in the |
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* decompressor framework |
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*/ |
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/* |
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* The reason that multiply two is that a CPU can request new I/O |
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* while it is waiting previous request. |
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*/ |
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#define MAX_DECOMPRESSOR (num_online_cpus() * 2) |
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int squashfs_max_decompressors(void) |
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{ |
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return MAX_DECOMPRESSOR; |
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} |
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struct squashfs_stream { |
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void *comp_opts; |
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struct list_head strm_list; |
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struct mutex mutex; |
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int avail_decomp; |
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wait_queue_head_t wait; |
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}; |
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struct decomp_stream { |
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void *stream; |
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struct list_head list; |
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}; |
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static void put_decomp_stream(struct decomp_stream *decomp_strm, |
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struct squashfs_stream *stream) |
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{ |
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mutex_lock(&stream->mutex); |
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list_add(&decomp_strm->list, &stream->strm_list); |
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mutex_unlock(&stream->mutex); |
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wake_up(&stream->wait); |
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} |
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void *squashfs_decompressor_create(struct squashfs_sb_info *msblk, |
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void *comp_opts) |
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{ |
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struct squashfs_stream *stream; |
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struct decomp_stream *decomp_strm = NULL; |
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int err = -ENOMEM; |
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stream = kzalloc(sizeof(*stream), GFP_KERNEL); |
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if (!stream) |
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goto out; |
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stream->comp_opts = comp_opts; |
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mutex_init(&stream->mutex); |
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INIT_LIST_HEAD(&stream->strm_list); |
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init_waitqueue_head(&stream->wait); |
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/* |
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* We should have a decompressor at least as default |
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* so if we fail to allocate new decompressor dynamically, |
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* we could always fall back to default decompressor and |
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* file system works. |
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*/ |
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decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL); |
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if (!decomp_strm) |
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goto out; |
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decomp_strm->stream = msblk->decompressor->init(msblk, |
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stream->comp_opts); |
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if (IS_ERR(decomp_strm->stream)) { |
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err = PTR_ERR(decomp_strm->stream); |
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goto out; |
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} |
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list_add(&decomp_strm->list, &stream->strm_list); |
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stream->avail_decomp = 1; |
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return stream; |
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out: |
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kfree(decomp_strm); |
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kfree(stream); |
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return ERR_PTR(err); |
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} |
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void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk) |
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{ |
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struct squashfs_stream *stream = msblk->stream; |
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if (stream) { |
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struct decomp_stream *decomp_strm; |
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while (!list_empty(&stream->strm_list)) { |
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decomp_strm = list_entry(stream->strm_list.prev, |
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struct decomp_stream, list); |
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list_del(&decomp_strm->list); |
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msblk->decompressor->free(decomp_strm->stream); |
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kfree(decomp_strm); |
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stream->avail_decomp--; |
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} |
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WARN_ON(stream->avail_decomp); |
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kfree(stream->comp_opts); |
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kfree(stream); |
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} |
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} |
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static struct decomp_stream *get_decomp_stream(struct squashfs_sb_info *msblk, |
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struct squashfs_stream *stream) |
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{ |
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struct decomp_stream *decomp_strm; |
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while (1) { |
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mutex_lock(&stream->mutex); |
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/* There is available decomp_stream */ |
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if (!list_empty(&stream->strm_list)) { |
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decomp_strm = list_entry(stream->strm_list.prev, |
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struct decomp_stream, list); |
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list_del(&decomp_strm->list); |
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mutex_unlock(&stream->mutex); |
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break; |
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} |
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/* |
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* If there is no available decomp and already full, |
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* let's wait for releasing decomp from other users. |
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*/ |
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if (stream->avail_decomp >= MAX_DECOMPRESSOR) |
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goto wait; |
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/* Let's allocate new decomp */ |
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decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL); |
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if (!decomp_strm) |
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goto wait; |
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decomp_strm->stream = msblk->decompressor->init(msblk, |
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stream->comp_opts); |
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if (IS_ERR(decomp_strm->stream)) { |
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kfree(decomp_strm); |
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goto wait; |
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} |
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stream->avail_decomp++; |
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WARN_ON(stream->avail_decomp > MAX_DECOMPRESSOR); |
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mutex_unlock(&stream->mutex); |
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break; |
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wait: |
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/* |
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* If system memory is tough, let's for other's |
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* releasing instead of hurting VM because it could |
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* make page cache thrashing. |
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*/ |
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mutex_unlock(&stream->mutex); |
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wait_event(stream->wait, |
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!list_empty(&stream->strm_list)); |
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} |
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return decomp_strm; |
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} |
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int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio, |
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int offset, int length, |
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struct squashfs_page_actor *output) |
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{ |
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int res; |
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struct squashfs_stream *stream = msblk->stream; |
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struct decomp_stream *decomp_stream = get_decomp_stream(msblk, stream); |
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res = msblk->decompressor->decompress(msblk, decomp_stream->stream, |
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bio, offset, length, output); |
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put_decomp_stream(decomp_stream, stream); |
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if (res < 0) |
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ERROR("%s decompression failed, data probably corrupt\n", |
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msblk->decompressor->name); |
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return res; |
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}
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