// SPDX-License-Identifier: GPL-2.0-or-later/* * Squashfs - a compressed read only filesystem for Linux * * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 * Phillip Lougher <phillip@squashfs.org.uk> * * zlib_wrapper.c */  #include <linux/mutex.h>#include <linux/bio.h>#include <linux/slab.h>#include <linux/zlib.h>#include <linux/vmalloc.h> #include "squashfs_fs.h"#include "squashfs_fs_sb.h"#include "squashfs.h"#include "decompressor.h"#include "page_actor.h" static void *zlib_init(struct squashfs_sb_info *dummy, void *buff){	z_stream *stream = kmalloc_obj(z_stream);	if (stream == NULL)		goto failed;	stream->workspace = vmalloc(zlib_inflate_workspacesize());	if (stream->workspace == NULL)		goto failed; 	return stream; failed:	ERROR("Failed to allocate zlib workspace\n");	kfree(stream);	return ERR_PTR(-ENOMEM);}  static void zlib_free(void *strm){	z_stream *stream = strm; 	if (stream)		vfree(stream->workspace);	kfree(stream);}  static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,	struct bio *bio, int offset, int length,	struct squashfs_page_actor *output){	struct bvec_iter_all iter_all = {};	struct bio_vec *bvec = bvec_init_iter_all(&iter_all);	int zlib_init = 0, error = 0;	z_stream *stream = strm; 	stream->avail_out = PAGE_SIZE;	stream->next_out = squashfs_first_page(output);	stream->avail_in = 0; 	if (IS_ERR(stream->next_out)) {		error = PTR_ERR(stream->next_out);		goto finish;	} 	for (;;) {		int zlib_err; 		if (stream->avail_in == 0) {			const void *data;			int avail; 			if (!bio_next_segment(bio, &iter_all)) {				/* Z_STREAM_END must be reached. */				error = -EIO;				break;			} 			avail = min(length, ((int)bvec->bv_len) - offset);			data = bvec_virt(bvec);			length -= avail;			stream->next_in = data + offset;			stream->avail_in = avail;			offset = 0;		} 		if (stream->avail_out == 0) {			stream->next_out = squashfs_next_page(output);			if (IS_ERR(stream->next_out)) {				error = PTR_ERR(stream->next_out);				break;			} else if (stream->next_out != NULL)				stream->avail_out = PAGE_SIZE;		} 		if (!zlib_init) {			zlib_err = zlib_inflateInit(stream);			if (zlib_err != Z_OK) {				error = -EIO;				break;			}			zlib_init = 1;		} 		zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);		if (zlib_err == Z_STREAM_END)			break;		if (zlib_err != Z_OK) {			error = -EIO;			break;		}	} finish:	squashfs_finish_page(output); 	if (!error)		if (zlib_inflateEnd(stream) != Z_OK)			error = -EIO; 	return error ? error : stream->total_out;} const struct squashfs_decompressor squashfs_zlib_comp_ops = {	.init = zlib_init,	.free = zlib_free,	.decompress = zlib_uncompress,	.id = ZLIB_COMPRESSION,	.name = "zlib",	.alloc_buffer = 1,	.supported = 1};