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)
34 static void zcomp_strm_free(struct zcomp_strm *zstrm)
36 if (!IS_ERR_OR_NULL(zstrm->tfm))
37 crypto_free_comp(zstrm->tfm);
38 free_pages((unsigned long)zstrm->buffer, 1);
44 * Initialize zcomp_strm structure with ->tfm initialized by backend, and
45 * ->buffer. Return a negative value on error.
47 static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp)
49 zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0);
51 * allocate 2 pages. 1 for compressed data, plus 1 extra for the
52 * case when compressed size is larger than the original one
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);
62 bool zcomp_available_algorithm(const char *comp)
65 * Crypto does not ignore a trailing new line symbol,
66 * so make sure you don't supply a string containing
68 * This also means that we permit zcomp initialisation
69 * with any compressing algorithm known to crypto api.
71 return crypto_has_comp(comp, 0, 0) == 1;
74 /* show available compressors */
75 ssize_t zcomp_available_show(const char *comp, char *buf)
77 bool known_algorithm = false;
81 for (i = 0; i < ARRAY_SIZE(backends); i++) {
82 if (!strcmp(comp, backends[i])) {
83 known_algorithm = true;
84 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
85 "[%s] ", backends[i]);
87 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
93 * Out-of-tree module known to crypto api or a missing
94 * entry in `backends'.
96 if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1)
97 sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
100 sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
104 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
106 local_lock(&comp->stream->lock);
107 return this_cpu_ptr(comp->stream);
110 void zcomp_stream_put(struct zcomp *comp)
112 local_unlock(&comp->stream->lock);
115 int zcomp_compress(struct zcomp_strm *zstrm,
116 const void *src, unsigned int *dst_len)
119 * Our dst memory (zstrm->buffer) is always `2 * PAGE_SIZE' sized
120 * because sometimes we can endup having a bigger compressed data
121 * due to various reasons: for example compression algorithms tend
122 * to add some padding to the compressed buffer. Speaking of padding,
123 * comp algorithm `842' pads the compressed length to multiple of 8
124 * and returns -ENOSP when the dst memory is not big enough, which
125 * is not something that ZRAM wants to see. We can handle the
126 * `compressed_size > PAGE_SIZE' case easily in ZRAM, but when we
127 * receive -ERRNO from the compressing backend we can't help it
128 * anymore. To make `842' happy we need to tell the exact size of
129 * the dst buffer, zram_drv will take care of the fact that
130 * compressed buffer is too big.
132 *dst_len = PAGE_SIZE * 2;
134 return crypto_comp_compress(zstrm->tfm,
136 zstrm->buffer, dst_len);
139 int zcomp_decompress(struct zcomp_strm *zstrm,
140 const void *src, unsigned int src_len, void *dst)
142 unsigned int dst_len = PAGE_SIZE;
144 return crypto_comp_decompress(zstrm->tfm,
149 int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
151 struct zcomp *comp = hlist_entry(node, struct zcomp, node);
152 struct zcomp_strm *zstrm;
155 zstrm = per_cpu_ptr(comp->stream, cpu);
156 local_lock_init(&zstrm->lock);
158 ret = zcomp_strm_init(zstrm, comp);
160 pr_err("Can't allocate a compression stream\n");
164 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)
166 struct zcomp *comp = hlist_entry(node, struct zcomp, node);
167 struct zcomp_strm *zstrm;
169 zstrm = per_cpu_ptr(comp->stream, cpu);
170 zcomp_strm_free(zstrm);
174 static int zcomp_init(struct zcomp *comp)
178 comp->stream = alloc_percpu(struct zcomp_strm);
182 ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
188 free_percpu(comp->stream);
192 void zcomp_destroy(struct zcomp *comp)
194 cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
195 free_percpu(comp->stream);
200 * search available compressors for requested algorithm.
201 * allocate new zcomp and initialize it. return compressing
202 * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL)
203 * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in
204 * case of allocation error, or any other error potentially
205 * returned by zcomp_init().
207 struct zcomp *zcomp_create(const char *compress)
213 * Crypto API will execute /sbin/modprobe if the compression module
214 * is not loaded yet. We must do it here, otherwise we are about to
215 * call /sbin/modprobe under CPU hot-plug lock.
217 if (!zcomp_available_algorithm(compress))
218 return ERR_PTR(-EINVAL);
220 comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
222 return ERR_PTR(-ENOMEM);
224 comp->name = compress;
225 error = zcomp_init(comp);
228 return ERR_PTR(error);