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/bio.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_dstream_workspace_bound(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 bio *bio, 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 int error = 0; 69 zstd_in_buffer in_buf = { NULL, 0, 0 }; 70 zstd_out_buffer out_buf = { NULL, 0, 0 }; 71 struct bvec_iter_all iter_all = {}; 72 struct bio_vec *bvec = bvec_init_iter_all(&iter_all); 73 74 stream = zstd_init_dstream(wksp->window_size, wksp->mem, wksp->mem_size); 75 76 if (!stream) { 77 ERROR("Failed to initialize zstd decompressor\n"); 78 return -EIO; 79 } 80 81 out_buf.size = PAGE_SIZE; 82 out_buf.dst = squashfs_first_page(output); 83 84 for (;;) { 85 size_t zstd_err; 86 87 if (in_buf.pos == in_buf.size) { 88 const void *data; 89 int avail; 90 91 if (!bio_next_segment(bio, &iter_all)) { 92 error = -EIO; 93 break; 94 } 95 96 avail = min(length, ((int)bvec->bv_len) - offset); 97 data = bvec_virt(bvec); 98 length -= avail; 99 in_buf.src = data + offset; 100 in_buf.size = avail; 101 in_buf.pos = 0; 102 offset = 0; 103 } 104 105 if (out_buf.pos == out_buf.size) { 106 out_buf.dst = squashfs_next_page(output); 107 if (out_buf.dst == NULL) { 108 /* Shouldn't run out of pages 109 * before stream is done. 110 */ 111 error = -EIO; 112 break; 113 } 114 out_buf.pos = 0; 115 out_buf.size = PAGE_SIZE; 116 } 117 118 total_out -= out_buf.pos; 119 zstd_err = zstd_decompress_stream(stream, &out_buf, &in_buf); 120 total_out += out_buf.pos; /* add the additional data produced */ 121 if (zstd_err == 0) 122 break; 123 124 if (zstd_is_error(zstd_err)) { 125 ERROR("zstd decompression error: %d\n", 126 (int)zstd_get_error_code(zstd_err)); 127 error = -EIO; 128 break; 129 } 130 } 131 132 squashfs_finish_page(output); 133 134 return error ? error : total_out; 135 } 136 137 const struct squashfs_decompressor squashfs_zstd_comp_ops = { 138 .init = zstd_init, 139 .free = zstd_free, 140 .decompress = zstd_uncompress, 141 .id = ZSTD_COMPRESSION, 142 .name = "zstd", 143 .supported = 1 144 }; 145