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[] = {
20 #if IS_ENABLED(CONFIG_CRYPTO_LZ4)
23 #if IS_ENABLED(CONFIG_CRYPTO_LZ4HC)
26 #if IS_ENABLED(CONFIG_CRYPTO_842)
29 #if IS_ENABLED(CONFIG_CRYPTO_ZSTD)
35 static void zcomp_strm_free(struct zcomp_strm *zstrm)
37 if (!IS_ERR_OR_NULL(zstrm->tfm))
38 crypto_free_comp(zstrm->tfm);
39 free_pages((unsigned long)zstrm->buffer, 1);
45 * Initialize zcomp_strm structure with ->tfm initialized by backend, and
46 * ->buffer. Return a negative value on error.
48 static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp)
50 zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0);
52 * allocate 2 pages. 1 for compressed data, plus 1 extra for the
53 * case when compressed size is larger than the original one
55 zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
56 if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) {
57 zcomp_strm_free(zstrm);
63 bool zcomp_available_algorithm(const char *comp)
67 i = __sysfs_match_string(backends, -1, comp);
72 * Crypto does not ignore a trailing new line symbol,
73 * so make sure you don't supply a string containing
75 * This also means that we permit zcomp initialisation
76 * with any compressing algorithm known to crypto api.
78 return crypto_has_comp(comp, 0, 0) == 1;
81 /* show available compressors */
82 ssize_t zcomp_available_show(const char *comp, char *buf)
84 bool known_algorithm = false;
88 for (; backends[i]; i++) {
89 if (!strcmp(comp, backends[i])) {
90 known_algorithm = true;
91 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
92 "[%s] ", backends[i]);
94 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
100 * Out-of-tree module known to crypto api or a missing
101 * entry in `backends'.
103 if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1)
104 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
107 sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
111 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
113 return get_cpu_ptr(comp->stream);
116 void zcomp_stream_put(struct zcomp *comp)
118 put_cpu_ptr(comp->stream);
121 int zcomp_compress(struct zcomp_strm *zstrm,
122 const void *src, unsigned int *dst_len)
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.
138 *dst_len = PAGE_SIZE * 2;
140 return crypto_comp_compress(zstrm->tfm,
142 zstrm->buffer, dst_len);
145 int zcomp_decompress(struct zcomp_strm *zstrm,
146 const void *src, unsigned int src_len, void *dst)
148 unsigned int dst_len = PAGE_SIZE;
150 return crypto_comp_decompress(zstrm->tfm,
155 int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
157 struct zcomp *comp = hlist_entry(node, struct zcomp, node);
158 struct zcomp_strm *zstrm;
161 zstrm = per_cpu_ptr(comp->stream, cpu);
162 ret = zcomp_strm_init(zstrm, comp);
164 pr_err("Can't allocate a compression stream\n");
168 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)
170 struct zcomp *comp = hlist_entry(node, struct zcomp, node);
171 struct zcomp_strm *zstrm;
173 zstrm = per_cpu_ptr(comp->stream, cpu);
174 zcomp_strm_free(zstrm);
178 static int zcomp_init(struct zcomp *comp)
182 comp->stream = alloc_percpu(struct zcomp_strm);
186 ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
192 free_percpu(comp->stream);
196 void zcomp_destroy(struct zcomp *comp)
198 cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
199 free_percpu(comp->stream);
204 * search available compressors for requested algorithm.
205 * allocate new zcomp and initialize it. return compressing
206 * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL)
207 * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in
208 * case of allocation error, or any other error potentially
209 * returned by zcomp_init().
211 struct zcomp *zcomp_create(const char *compress)
216 if (!zcomp_available_algorithm(compress))
217 return ERR_PTR(-EINVAL);
219 comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
221 return ERR_PTR(-ENOMEM);
223 comp->name = compress;
224 error = zcomp_init(comp);
227 return ERR_PTR(error);