1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2014 Sergey Senozhatsky. 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/string.h> 8 #include <linux/err.h> 9 #include <linux/slab.h> 10 #include <linux/wait.h> 11 #include <linux/sched.h> 12 #include <linux/cpu.h> 13 #include <linux/crypto.h> 14 15 #include "zcomp.h" 16 17 static const char * const backends[] = { 18 #if IS_ENABLED(CONFIG_CRYPTO_LZO) 19 "lzo", 20 "lzo-rle", 21 #endif 22 #if IS_ENABLED(CONFIG_CRYPTO_LZ4) 23 "lz4", 24 #endif 25 #if IS_ENABLED(CONFIG_CRYPTO_LZ4HC) 26 "lz4hc", 27 #endif 28 #if IS_ENABLED(CONFIG_CRYPTO_842) 29 "842", 30 #endif 31 #if IS_ENABLED(CONFIG_CRYPTO_ZSTD) 32 "zstd", 33 #endif 34 }; 35 36 static void zcomp_strm_free(struct zcomp_strm *zstrm) 37 { 38 if (!IS_ERR_OR_NULL(zstrm->tfm)) 39 crypto_free_comp(zstrm->tfm); 40 free_pages((unsigned long)zstrm->buffer, 1); 41 zstrm->tfm = NULL; 42 zstrm->buffer = NULL; 43 } 44 45 /* 46 * Initialize zcomp_strm structure with ->tfm initialized by backend, and 47 * ->buffer. Return a negative value on error. 48 */ 49 static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp) 50 { 51 zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0); 52 /* 53 * allocate 2 pages. 1 for compressed data, plus 1 extra for the 54 * case when compressed size is larger than the original one 55 */ 56 zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); 57 if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) { 58 zcomp_strm_free(zstrm); 59 return -ENOMEM; 60 } 61 return 0; 62 } 63 64 bool zcomp_available_algorithm(const char *comp) 65 { 66 int i; 67 68 i = sysfs_match_string(backends, comp); 69 if (i >= 0) 70 return true; 71 72 /* 73 * Crypto does not ignore a trailing new line symbol, 74 * so make sure you don't supply a string containing 75 * one. 76 * This also means that we permit zcomp initialisation 77 * with any compressing algorithm known to crypto api. 78 */ 79 return crypto_has_comp(comp, 0, 0) == 1; 80 } 81 82 /* show available compressors */ 83 ssize_t zcomp_available_show(const char *comp, char *buf) 84 { 85 bool known_algorithm = false; 86 ssize_t sz = 0; 87 int i; 88 89 for (i = 0; i < ARRAY_SIZE(backends); i++) { 90 if (!strcmp(comp, backends[i])) { 91 known_algorithm = true; 92 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 93 "[%s] ", backends[i]); 94 } else { 95 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 96 "%s ", backends[i]); 97 } 98 } 99 100 /* 101 * Out-of-tree module known to crypto api or a missing 102 * entry in `backends'. 103 */ 104 if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1) 105 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 106 "[%s] ", comp); 107 108 sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n"); 109 return sz; 110 } 111 112 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) 113 { 114 local_lock(&comp->stream->lock); 115 return this_cpu_ptr(comp->stream); 116 } 117 118 void zcomp_stream_put(struct zcomp *comp) 119 { 120 local_unlock(&comp->stream->lock); 121 } 122 123 int zcomp_compress(struct zcomp_strm *zstrm, 124 const void *src, unsigned int *dst_len) 125 { 126 /* 127 * Our dst memory (zstrm->buffer) is always `2 * PAGE_SIZE' sized 128 * because sometimes we can endup having a bigger compressed data 129 * due to various reasons: for example compression algorithms tend 130 * to add some padding to the compressed buffer. Speaking of padding, 131 * comp algorithm `842' pads the compressed length to multiple of 8 132 * and returns -ENOSP when the dst memory is not big enough, which 133 * is not something that ZRAM wants to see. We can handle the 134 * `compressed_size > PAGE_SIZE' case easily in ZRAM, but when we 135 * receive -ERRNO from the compressing backend we can't help it 136 * anymore. To make `842' happy we need to tell the exact size of 137 * the dst buffer, zram_drv will take care of the fact that 138 * compressed buffer is too big. 139 */ 140 *dst_len = PAGE_SIZE * 2; 141 142 return crypto_comp_compress(zstrm->tfm, 143 src, PAGE_SIZE, 144 zstrm->buffer, dst_len); 145 } 146 147 int zcomp_decompress(struct zcomp_strm *zstrm, 148 const void *src, unsigned int src_len, void *dst) 149 { 150 unsigned int dst_len = PAGE_SIZE; 151 152 return crypto_comp_decompress(zstrm->tfm, 153 src, src_len, 154 dst, &dst_len); 155 } 156 157 int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) 158 { 159 struct zcomp *comp = hlist_entry(node, struct zcomp, node); 160 struct zcomp_strm *zstrm; 161 int ret; 162 163 zstrm = per_cpu_ptr(comp->stream, cpu); 164 local_lock_init(&zstrm->lock); 165 166 ret = zcomp_strm_init(zstrm, comp); 167 if (ret) 168 pr_err("Can't allocate a compression stream\n"); 169 return ret; 170 } 171 172 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node) 173 { 174 struct zcomp *comp = hlist_entry(node, struct zcomp, node); 175 struct zcomp_strm *zstrm; 176 177 zstrm = per_cpu_ptr(comp->stream, cpu); 178 zcomp_strm_free(zstrm); 179 return 0; 180 } 181 182 static int zcomp_init(struct zcomp *comp) 183 { 184 int ret; 185 186 comp->stream = alloc_percpu(struct zcomp_strm); 187 if (!comp->stream) 188 return -ENOMEM; 189 190 ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node); 191 if (ret < 0) 192 goto cleanup; 193 return 0; 194 195 cleanup: 196 free_percpu(comp->stream); 197 return ret; 198 } 199 200 void zcomp_destroy(struct zcomp *comp) 201 { 202 cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node); 203 free_percpu(comp->stream); 204 kfree(comp); 205 } 206 207 /* 208 * search available compressors for requested algorithm. 209 * allocate new zcomp and initialize it. return compressing 210 * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL) 211 * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in 212 * case of allocation error, or any other error potentially 213 * returned by zcomp_init(). 214 */ 215 struct zcomp *zcomp_create(const char *compress) 216 { 217 struct zcomp *comp; 218 int error; 219 220 if (!zcomp_available_algorithm(compress)) 221 return ERR_PTR(-EINVAL); 222 223 comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL); 224 if (!comp) 225 return ERR_PTR(-ENOMEM); 226 227 comp->name = compress; 228 error = zcomp_init(comp); 229 if (error) { 230 kfree(comp); 231 return ERR_PTR(error); 232 } 233 return comp; 234 } 235