1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2014 Sergey Senozhatsky.
6 #include <linux/kernel.h>
7 #include <linux/string.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>
17 static const char * const backends[] = {
18 #if IS_ENABLED(CONFIG_CRYPTO_LZO)
22 #if IS_ENABLED(CONFIG_CRYPTO_LZ4)
25 #if IS_ENABLED(CONFIG_CRYPTO_LZ4HC)
28 #if IS_ENABLED(CONFIG_CRYPTO_842)
31 #if IS_ENABLED(CONFIG_CRYPTO_ZSTD)
36 static void zcomp_strm_free(struct zcomp_strm *zstrm)
38 if (!IS_ERR_OR_NULL(zstrm->tfm))
39 crypto_free_comp(zstrm->tfm);
40 free_pages((unsigned long)zstrm->buffer, 1);
46 * Initialize zcomp_strm structure with ->tfm initialized by backend, and
47 * ->buffer. Return a negative value on error.
49 static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp)
51 zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0);
53 * allocate 2 pages. 1 for compressed data, plus 1 extra for the
54 * case when compressed size is larger than the original one
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);
64 bool zcomp_available_algorithm(const char *comp)
68 i = sysfs_match_string(backends, comp);
73 * Crypto does not ignore a trailing new line symbol,
74 * so make sure you don't supply a string containing
76 * This also means that we permit zcomp initialisation
77 * with any compressing algorithm known to crypto api.
79 return crypto_has_comp(comp, 0, 0) == 1;
82 /* show available compressors */
83 ssize_t zcomp_available_show(const char *comp, char *buf)
85 bool known_algorithm = false;
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]);
95 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
101 * Out-of-tree module known to crypto api or a missing
102 * entry in `backends'.
104 if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1)
105 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
108 sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
112 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
114 local_lock(&comp->stream->lock);
115 return this_cpu_ptr(comp->stream);
118 void zcomp_stream_put(struct zcomp *comp)
120 local_unlock(&comp->stream->lock);
123 int zcomp_compress(struct zcomp_strm *zstrm,
124 const void *src, unsigned int *dst_len)
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.
140 *dst_len = PAGE_SIZE * 2;
142 return crypto_comp_compress(zstrm->tfm,
144 zstrm->buffer, dst_len);
147 int zcomp_decompress(struct zcomp_strm *zstrm,
148 const void *src, unsigned int src_len, void *dst)
150 unsigned int dst_len = PAGE_SIZE;
152 return crypto_comp_decompress(zstrm->tfm,
157 int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
159 struct zcomp *comp = hlist_entry(node, struct zcomp, node);
160 struct zcomp_strm *zstrm;
163 zstrm = per_cpu_ptr(comp->stream, cpu);
164 local_lock_init(&zstrm->lock);
166 ret = zcomp_strm_init(zstrm, comp);
168 pr_err("Can't allocate a compression stream\n");
172 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)
174 struct zcomp *comp = hlist_entry(node, struct zcomp, node);
175 struct zcomp_strm *zstrm;
177 zstrm = per_cpu_ptr(comp->stream, cpu);
178 zcomp_strm_free(zstrm);
182 static int zcomp_init(struct zcomp *comp)
186 comp->stream = alloc_percpu(struct zcomp_strm);
190 ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
196 free_percpu(comp->stream);
200 void zcomp_destroy(struct zcomp *comp)
202 cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
203 free_percpu(comp->stream);
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().
215 struct zcomp *zcomp_create(const char *compress)
220 if (!zcomp_available_algorithm(compress))
221 return ERR_PTR(-EINVAL);
223 comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
225 return ERR_PTR(-ENOMEM);
227 comp->name = compress;
228 error = zcomp_init(comp);
231 return ERR_PTR(error);