1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Squashfs - a compressed read only filesystem for Linux 4 * 5 * Copyright (c) 2016-present, Facebook, Inc. 6 * All rights reserved. 7 * 8 * zstd_wrapper.c 9 */ 10 11 #include <linux/mutex.h> 12 #include <linux/buffer_head.h> 13 #include <linux/slab.h> 14 #include <linux/zstd.h> 15 #include <linux/vmalloc.h> 16 17 #include "squashfs_fs.h" 18 #include "squashfs_fs_sb.h" 19 #include "squashfs.h" 20 #include "decompressor.h" 21 #include "page_actor.h" 22 23 struct workspace { 24 void *mem; 25 size_t mem_size; 26 size_t window_size; 27 }; 28 29 static void *zstd_init(struct squashfs_sb_info *msblk, void *buff) 30 { 31 struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL); 32 33 if (wksp == NULL) 34 goto failed; 35 wksp->window_size = max_t(size_t, 36 msblk->block_size, SQUASHFS_METADATA_SIZE); 37 wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size); 38 wksp->mem = vmalloc(wksp->mem_size); 39 if (wksp->mem == NULL) 40 goto failed; 41 42 return wksp; 43 44 failed: 45 ERROR("Failed to allocate zstd workspace\n"); 46 kfree(wksp); 47 return ERR_PTR(-ENOMEM); 48 } 49 50 51 static void zstd_free(void *strm) 52 { 53 struct workspace *wksp = strm; 54 55 if (wksp) 56 vfree(wksp->mem); 57 kfree(wksp); 58 } 59 60 61 static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm, 62 struct buffer_head **bh, int b, int offset, int length, 63 struct squashfs_page_actor *output) 64 { 65 struct workspace *wksp = strm; 66 ZSTD_DStream *stream; 67 size_t total_out = 0; 68 size_t zstd_err; 69 int k = 0; 70 ZSTD_inBuffer in_buf = { NULL, 0, 0 }; 71 ZSTD_outBuffer out_buf = { NULL, 0, 0 }; 72 73 stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size); 74 75 if (!stream) { 76 ERROR("Failed to initialize zstd decompressor\n"); 77 goto out; 78 } 79 80 out_buf.size = PAGE_SIZE; 81 out_buf.dst = squashfs_first_page(output); 82 83 do { 84 if (in_buf.pos == in_buf.size && k < b) { 85 int avail = min(length, msblk->devblksize - offset); 86 87 length -= avail; 88 in_buf.src = bh[k]->b_data + offset; 89 in_buf.size = avail; 90 in_buf.pos = 0; 91 offset = 0; 92 } 93 94 if (out_buf.pos == out_buf.size) { 95 out_buf.dst = squashfs_next_page(output); 96 if (out_buf.dst == NULL) { 97 /* Shouldn't run out of pages 98 * before stream is done. 99 */ 100 squashfs_finish_page(output); 101 goto out; 102 } 103 out_buf.pos = 0; 104 out_buf.size = PAGE_SIZE; 105 } 106 107 total_out -= out_buf.pos; 108 zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf); 109 total_out += out_buf.pos; /* add the additional data produced */ 110 111 if (in_buf.pos == in_buf.size && k < b) 112 put_bh(bh[k++]); 113 } while (zstd_err != 0 && !ZSTD_isError(zstd_err)); 114 115 squashfs_finish_page(output); 116 117 if (ZSTD_isError(zstd_err)) { 118 ERROR("zstd decompression error: %d\n", 119 (int)ZSTD_getErrorCode(zstd_err)); 120 goto out; 121 } 122 123 if (k < b) 124 goto out; 125 126 return (int)total_out; 127 128 out: 129 for (; k < b; k++) 130 put_bh(bh[k]); 131 132 return -EIO; 133 } 134 135 const struct squashfs_decompressor squashfs_zstd_comp_ops = { 136 .init = zstd_init, 137 .free = zstd_free, 138 .decompress = zstd_uncompress, 139 .id = ZSTD_COMPRESSION, 140 .name = "zstd", 141 .supported = 1 142 }; 143