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