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