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 /* 67 * Crypto does not ignore a trailing new line symbol, 68 * so make sure you don't supply a string containing 69 * one. 70 * This also means that we permit zcomp initialisation 71 * with any compressing algorithm known to crypto api. 72 */ 73 return crypto_has_comp(comp, 0, 0) == 1; 74 } 75 76 /* show available compressors */ 77 ssize_t zcomp_available_show(const char *comp, char *buf) 78 { 79 bool known_algorithm = false; 80 ssize_t sz = 0; 81 int i; 82 83 for (i = 0; i < ARRAY_SIZE(backends); i++) { 84 if (!strcmp(comp, backends[i])) { 85 known_algorithm = true; 86 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 87 "[%s] ", backends[i]); 88 } else { 89 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 90 "%s ", backends[i]); 91 } 92 } 93 94 /* 95 * Out-of-tree module known to crypto api or a missing 96 * entry in `backends'. 97 */ 98 if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1) 99 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, 100 "[%s] ", comp); 101 102 sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n"); 103 return sz; 104 } 105 106 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) 107 { 108 local_lock(&comp->stream->lock); 109 return this_cpu_ptr(comp->stream); 110 } 111 112 void zcomp_stream_put(struct zcomp *comp) 113 { 114 local_unlock(&comp->stream->lock); 115 } 116 117 int zcomp_compress(struct zcomp_strm *zstrm, 118 const void *src, unsigned int *dst_len) 119 { 120 /* 121 * Our dst memory (zstrm->buffer) is always `2 * PAGE_SIZE' sized 122 * because sometimes we can endup having a bigger compressed data 123 * due to various reasons: for example compression algorithms tend 124 * to add some padding to the compressed buffer. Speaking of padding, 125 * comp algorithm `842' pads the compressed length to multiple of 8 126 * and returns -ENOSP when the dst memory is not big enough, which 127 * is not something that ZRAM wants to see. We can handle the 128 * `compressed_size > PAGE_SIZE' case easily in ZRAM, but when we 129 * receive -ERRNO from the compressing backend we can't help it 130 * anymore. To make `842' happy we need to tell the exact size of 131 * the dst buffer, zram_drv will take care of the fact that 132 * compressed buffer is too big. 133 */ 134 *dst_len = PAGE_SIZE * 2; 135 136 return crypto_comp_compress(zstrm->tfm, 137 src, PAGE_SIZE, 138 zstrm->buffer, dst_len); 139 } 140 141 int zcomp_decompress(struct zcomp_strm *zstrm, 142 const void *src, unsigned int src_len, void *dst) 143 { 144 unsigned int dst_len = PAGE_SIZE; 145 146 return crypto_comp_decompress(zstrm->tfm, 147 src, src_len, 148 dst, &dst_len); 149 } 150 151 int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) 152 { 153 struct zcomp *comp = hlist_entry(node, struct zcomp, node); 154 struct zcomp_strm *zstrm; 155 int ret; 156 157 zstrm = per_cpu_ptr(comp->stream, cpu); 158 local_lock_init(&zstrm->lock); 159 160 ret = zcomp_strm_init(zstrm, comp); 161 if (ret) 162 pr_err("Can't allocate a compression stream\n"); 163 return ret; 164 } 165 166 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node) 167 { 168 struct zcomp *comp = hlist_entry(node, struct zcomp, node); 169 struct zcomp_strm *zstrm; 170 171 zstrm = per_cpu_ptr(comp->stream, cpu); 172 zcomp_strm_free(zstrm); 173 return 0; 174 } 175 176 static int zcomp_init(struct zcomp *comp) 177 { 178 int ret; 179 180 comp->stream = alloc_percpu(struct zcomp_strm); 181 if (!comp->stream) 182 return -ENOMEM; 183 184 ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node); 185 if (ret < 0) 186 goto cleanup; 187 return 0; 188 189 cleanup: 190 free_percpu(comp->stream); 191 return ret; 192 } 193 194 void zcomp_destroy(struct zcomp *comp) 195 { 196 cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node); 197 free_percpu(comp->stream); 198 kfree(comp); 199 } 200 201 /* 202 * search available compressors for requested algorithm. 203 * allocate new zcomp and initialize it. return compressing 204 * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL) 205 * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in 206 * case of allocation error, or any other error potentially 207 * returned by zcomp_init(). 208 */ 209 struct zcomp *zcomp_create(const char *alg) 210 { 211 struct zcomp *comp; 212 int error; 213 214 /* 215 * Crypto API will execute /sbin/modprobe if the compression module 216 * is not loaded yet. We must do it here, otherwise we are about to 217 * call /sbin/modprobe under CPU hot-plug lock. 218 */ 219 if (!zcomp_available_algorithm(alg)) 220 return ERR_PTR(-EINVAL); 221 222 comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL); 223 if (!comp) 224 return ERR_PTR(-ENOMEM); 225 226 comp->name = alg; 227 error = zcomp_init(comp); 228 if (error) { 229 kfree(comp); 230 return ERR_PTR(error); 231 } 232 return comp; 233 } 234