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 "lzo", 19 "lzo-rle", 20 #if IS_ENABLED(CONFIG_CRYPTO_LZ4) 21 "lz4", 22 #endif 23 #if IS_ENABLED(CONFIG_CRYPTO_LZ4HC) 24 "lz4hc", 25 #endif 26 #if IS_ENABLED(CONFIG_CRYPTO_842) 27 "842", 28 #endif 29 #if IS_ENABLED(CONFIG_CRYPTO_ZSTD) 30 "zstd", 31 #endif 32 NULL 33 }; 34 35 static void zcomp_strm_free(struct zcomp_strm *zstrm) 36 { 37 if (!IS_ERR_OR_NULL(zstrm->tfm)) 38 crypto_free_comp(zstrm->tfm); 39 free_pages((unsigned long)zstrm->buffer, 1); 40 kfree(zstrm); 41 } 42 43 /* 44 * allocate new zcomp_strm structure with ->tfm initialized by 45 * backend, return NULL on error 46 */ 47 static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) 48 { 49 struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL); 50 if (!zstrm) 51 return NULL; 52 53 zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0); 54 /* 55 * allocate 2 pages. 1 for compressed data, plus 1 extra for the 56 * case when compressed size is larger than the original one 57 */ 58 zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); 59 if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) { 60 zcomp_strm_free(zstrm); 61 zstrm = NULL; 62 } 63 return zstrm; 64 } 65 66 bool zcomp_available_algorithm(const char *comp) 67 { 68 int i; 69 70 i = __sysfs_match_string(backends, -1, comp); 71 if (i >= 0) 72 return true; 73 74 /* 75 * Crypto does not ignore a trailing new line symbol, 76 * so make sure you don't supply a string containing 77 * one. 78 * This also means that we permit zcomp initialisation 79 * with any compressing algorithm known to crypto api. 80 */ 81 return crypto_has_comp(comp, 0, 0) == 1; 82 } 83 84 /* show available compressors */ 85 ssize_t zcomp_available_show(const char *comp, char *buf) 86 { 87 bool known_algorithm = false; 88 ssize_t sz = 0; 89 int i = 0; 90 91 for (; backends[i]; i++) { 92 if (!strcmp(comp, backends[i])) { 93 known_algorithm = true; 94 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 95 "[%s] ", backends[i]); 96 } else { 97 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 98 "%s ", backends[i]); 99 } 100 } 101 102 /* 103 * Out-of-tree module known to crypto api or a missing 104 * entry in `backends'. 105 */ 106 if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1) 107 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 108 "[%s] ", comp); 109 110 sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n"); 111 return sz; 112 } 113 114 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) 115 { 116 return *get_cpu_ptr(comp->stream); 117 } 118 119 void zcomp_stream_put(struct zcomp *comp) 120 { 121 put_cpu_ptr(comp->stream); 122 } 123 124 int zcomp_compress(struct zcomp_strm *zstrm, 125 const void *src, unsigned int *dst_len) 126 { 127 /* 128 * Our dst memory (zstrm->buffer) is always `2 * PAGE_SIZE' sized 129 * because sometimes we can endup having a bigger compressed data 130 * due to various reasons: for example compression algorithms tend 131 * to add some padding to the compressed buffer. Speaking of padding, 132 * comp algorithm `842' pads the compressed length to multiple of 8 133 * and returns -ENOSP when the dst memory is not big enough, which 134 * is not something that ZRAM wants to see. We can handle the 135 * `compressed_size > PAGE_SIZE' case easily in ZRAM, but when we 136 * receive -ERRNO from the compressing backend we can't help it 137 * anymore. To make `842' happy we need to tell the exact size of 138 * the dst buffer, zram_drv will take care of the fact that 139 * compressed buffer is too big. 140 */ 141 *dst_len = PAGE_SIZE * 2; 142 143 return crypto_comp_compress(zstrm->tfm, 144 src, PAGE_SIZE, 145 zstrm->buffer, dst_len); 146 } 147 148 int zcomp_decompress(struct zcomp_strm *zstrm, 149 const void *src, unsigned int src_len, void *dst) 150 { 151 unsigned int dst_len = PAGE_SIZE; 152 153 return crypto_comp_decompress(zstrm->tfm, 154 src, src_len, 155 dst, &dst_len); 156 } 157 158 int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) 159 { 160 struct zcomp *comp = hlist_entry(node, struct zcomp, node); 161 struct zcomp_strm *zstrm; 162 163 if (WARN_ON(*per_cpu_ptr(comp->stream, cpu))) 164 return 0; 165 166 zstrm = zcomp_strm_alloc(comp); 167 if (IS_ERR_OR_NULL(zstrm)) { 168 pr_err("Can't allocate a compression stream\n"); 169 return -ENOMEM; 170 } 171 *per_cpu_ptr(comp->stream, cpu) = zstrm; 172 return 0; 173 } 174 175 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node) 176 { 177 struct zcomp *comp = hlist_entry(node, struct zcomp, node); 178 struct zcomp_strm *zstrm; 179 180 zstrm = *per_cpu_ptr(comp->stream, cpu); 181 if (!IS_ERR_OR_NULL(zstrm)) 182 zcomp_strm_free(zstrm); 183 *per_cpu_ptr(comp->stream, cpu) = NULL; 184 return 0; 185 } 186 187 static int zcomp_init(struct zcomp *comp) 188 { 189 int ret; 190 191 comp->stream = alloc_percpu(struct zcomp_strm *); 192 if (!comp->stream) 193 return -ENOMEM; 194 195 ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node); 196 if (ret < 0) 197 goto cleanup; 198 return 0; 199 200 cleanup: 201 free_percpu(comp->stream); 202 return ret; 203 } 204 205 void zcomp_destroy(struct zcomp *comp) 206 { 207 cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node); 208 free_percpu(comp->stream); 209 kfree(comp); 210 } 211 212 /* 213 * search available compressors for requested algorithm. 214 * allocate new zcomp and initialize it. return compressing 215 * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL) 216 * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in 217 * case of allocation error, or any other error potentially 218 * returned by zcomp_init(). 219 */ 220 struct zcomp *zcomp_create(const char *compress) 221 { 222 struct zcomp *comp; 223 int error; 224 225 if (!zcomp_available_algorithm(compress)) 226 return ERR_PTR(-EINVAL); 227 228 comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL); 229 if (!comp) 230 return ERR_PTR(-ENOMEM); 231 232 comp->name = compress; 233 error = zcomp_init(comp); 234 if (error) { 235 kfree(comp); 236 return ERR_PTR(error); 237 } 238 return comp; 239 } 240