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-rw-r--r--fs/squashfs/lz4_wrapper.c146
1 files changed, 146 insertions, 0 deletions
diff --git a/fs/squashfs/lz4_wrapper.c b/fs/squashfs/lz4_wrapper.c
new file mode 100644
index 000000000..49797729f
--- /dev/null
+++ b/fs/squashfs/lz4_wrapper.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2013, 2014
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ */
+
+#include <linux/bio.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/lz4.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+#include "page_actor.h"
+
+#define LZ4_LEGACY 1
+
+struct lz4_comp_opts {
+ __le32 version;
+ __le32 flags;
+};
+
+struct squashfs_lz4 {
+ void *input;
+ void *output;
+};
+
+
+static void *lz4_comp_opts(struct squashfs_sb_info *msblk,
+ void *buff, int len)
+{
+ struct lz4_comp_opts *comp_opts = buff;
+
+ /* LZ4 compressed filesystems always have compression options */
+ if (comp_opts == NULL || len < sizeof(*comp_opts))
+ return ERR_PTR(-EIO);
+
+ if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {
+ /* LZ4 format currently used by the kernel is the 'legacy'
+ * format */
+ ERROR("Unknown LZ4 version\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ return NULL;
+}
+
+
+static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)
+{
+ int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
+ struct squashfs_lz4 *stream;
+
+ stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+ if (stream == NULL)
+ goto failed;
+ stream->input = vmalloc(block_size);
+ if (stream->input == NULL)
+ goto failed2;
+ stream->output = vmalloc(block_size);
+ if (stream->output == NULL)
+ goto failed3;
+
+ return stream;
+
+failed3:
+ vfree(stream->input);
+failed2:
+ kfree(stream);
+failed:
+ ERROR("Failed to initialise LZ4 decompressor\n");
+ return ERR_PTR(-ENOMEM);
+}
+
+
+static void lz4_free(void *strm)
+{
+ struct squashfs_lz4 *stream = strm;
+
+ if (stream) {
+ vfree(stream->input);
+ vfree(stream->output);
+ }
+ kfree(stream);
+}
+
+
+static int lz4_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);
+ struct squashfs_lz4 *stream = strm;
+ void *buff = stream->input, *data;
+ int bytes = length, res;
+
+ while (bio_next_segment(bio, &iter_all)) {
+ int avail = min(bytes, ((int)bvec->bv_len) - offset);
+
+ data = bvec_virt(bvec);
+ memcpy(buff, data + offset, avail);
+ buff += avail;
+ bytes -= avail;
+ offset = 0;
+ }
+
+ res = LZ4_decompress_safe(stream->input, stream->output,
+ length, output->length);
+
+ if (res < 0)
+ return -EIO;
+
+ bytes = res;
+ data = squashfs_first_page(output);
+ buff = stream->output;
+ while (data) {
+ if (bytes <= PAGE_SIZE) {
+ if (!IS_ERR(data))
+ memcpy(data, buff, bytes);
+ break;
+ }
+ if (!IS_ERR(data))
+ memcpy(data, buff, PAGE_SIZE);
+ buff += PAGE_SIZE;
+ bytes -= PAGE_SIZE;
+ data = squashfs_next_page(output);
+ }
+ squashfs_finish_page(output);
+
+ return res;
+}
+
+const struct squashfs_decompressor squashfs_lz4_comp_ops = {
+ .init = lz4_init,
+ .comp_opts = lz4_comp_opts,
+ .free = lz4_free,
+ .decompress = lz4_uncompress,
+ .id = LZ4_COMPRESSION,
+ .name = "lz4",
+ .alloc_buffer = 0,
+ .supported = 1
+};