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234 lines
5.6 KiB
234 lines
5.6 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (C) 2014 Sergey Senozhatsky. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/string.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <linux/wait.h> |
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#include <linux/sched.h> |
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#include <linux/cpu.h> |
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#include <linux/crypto.h> |
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#include "zcomp.h" |
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static const char * const backends[] = { |
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#if IS_ENABLED(CONFIG_CRYPTO_LZO) |
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"lzo", |
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"lzo-rle", |
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#endif |
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#if IS_ENABLED(CONFIG_CRYPTO_LZ4) |
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"lz4", |
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#endif |
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#if IS_ENABLED(CONFIG_CRYPTO_LZ4HC) |
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"lz4hc", |
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#endif |
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#if IS_ENABLED(CONFIG_CRYPTO_842) |
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"842", |
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#endif |
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#if IS_ENABLED(CONFIG_CRYPTO_ZSTD) |
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"zstd", |
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#endif |
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}; |
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static void zcomp_strm_free(struct zcomp_strm *zstrm) |
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{ |
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if (!IS_ERR_OR_NULL(zstrm->tfm)) |
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crypto_free_comp(zstrm->tfm); |
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free_pages((unsigned long)zstrm->buffer, 1); |
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zstrm->tfm = NULL; |
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zstrm->buffer = NULL; |
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} |
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/* |
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* Initialize zcomp_strm structure with ->tfm initialized by backend, and |
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* ->buffer. Return a negative value on error. |
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*/ |
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static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp) |
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{ |
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zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0); |
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/* |
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* allocate 2 pages. 1 for compressed data, plus 1 extra for the |
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* case when compressed size is larger than the original one |
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*/ |
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zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); |
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if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) { |
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zcomp_strm_free(zstrm); |
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return -ENOMEM; |
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} |
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return 0; |
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} |
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bool zcomp_available_algorithm(const char *comp) |
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{ |
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int i; |
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i = sysfs_match_string(backends, comp); |
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if (i >= 0) |
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return true; |
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/* |
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* Crypto does not ignore a trailing new line symbol, |
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* so make sure you don't supply a string containing |
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* one. |
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* This also means that we permit zcomp initialisation |
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* with any compressing algorithm known to crypto api. |
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*/ |
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return crypto_has_comp(comp, 0, 0) == 1; |
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} |
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/* show available compressors */ |
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ssize_t zcomp_available_show(const char *comp, char *buf) |
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{ |
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bool known_algorithm = false; |
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ssize_t sz = 0; |
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int i; |
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for (i = 0; i < ARRAY_SIZE(backends); i++) { |
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if (!strcmp(comp, backends[i])) { |
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known_algorithm = true; |
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sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, |
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"[%s] ", backends[i]); |
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} else { |
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sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, |
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"%s ", backends[i]); |
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} |
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} |
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/* |
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* Out-of-tree module known to crypto api or a missing |
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* entry in `backends'. |
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*/ |
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if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1) |
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sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, |
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"[%s] ", comp); |
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sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n"); |
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return sz; |
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} |
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struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) |
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{ |
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local_lock(&comp->stream->lock); |
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return this_cpu_ptr(comp->stream); |
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} |
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void zcomp_stream_put(struct zcomp *comp) |
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{ |
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local_unlock(&comp->stream->lock); |
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} |
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int zcomp_compress(struct zcomp_strm *zstrm, |
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const void *src, unsigned int *dst_len) |
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{ |
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/* |
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* Our dst memory (zstrm->buffer) is always `2 * PAGE_SIZE' sized |
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* because sometimes we can endup having a bigger compressed data |
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* due to various reasons: for example compression algorithms tend |
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* to add some padding to the compressed buffer. Speaking of padding, |
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* comp algorithm `842' pads the compressed length to multiple of 8 |
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* and returns -ENOSP when the dst memory is not big enough, which |
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* is not something that ZRAM wants to see. We can handle the |
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* `compressed_size > PAGE_SIZE' case easily in ZRAM, but when we |
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* receive -ERRNO from the compressing backend we can't help it |
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* anymore. To make `842' happy we need to tell the exact size of |
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* the dst buffer, zram_drv will take care of the fact that |
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* compressed buffer is too big. |
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*/ |
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*dst_len = PAGE_SIZE * 2; |
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return crypto_comp_compress(zstrm->tfm, |
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src, PAGE_SIZE, |
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zstrm->buffer, dst_len); |
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} |
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int zcomp_decompress(struct zcomp_strm *zstrm, |
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const void *src, unsigned int src_len, void *dst) |
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{ |
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unsigned int dst_len = PAGE_SIZE; |
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return crypto_comp_decompress(zstrm->tfm, |
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src, src_len, |
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dst, &dst_len); |
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} |
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int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) |
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{ |
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struct zcomp *comp = hlist_entry(node, struct zcomp, node); |
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struct zcomp_strm *zstrm; |
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int ret; |
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zstrm = per_cpu_ptr(comp->stream, cpu); |
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local_lock_init(&zstrm->lock); |
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ret = zcomp_strm_init(zstrm, comp); |
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if (ret) |
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pr_err("Can't allocate a compression stream\n"); |
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return ret; |
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} |
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int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node) |
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{ |
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struct zcomp *comp = hlist_entry(node, struct zcomp, node); |
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struct zcomp_strm *zstrm; |
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zstrm = per_cpu_ptr(comp->stream, cpu); |
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zcomp_strm_free(zstrm); |
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return 0; |
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} |
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static int zcomp_init(struct zcomp *comp) |
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{ |
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int ret; |
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comp->stream = alloc_percpu(struct zcomp_strm); |
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if (!comp->stream) |
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return -ENOMEM; |
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ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node); |
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if (ret < 0) |
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goto cleanup; |
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return 0; |
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cleanup: |
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free_percpu(comp->stream); |
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return ret; |
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} |
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void zcomp_destroy(struct zcomp *comp) |
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{ |
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cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node); |
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free_percpu(comp->stream); |
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kfree(comp); |
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} |
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/* |
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* search available compressors for requested algorithm. |
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* allocate new zcomp and initialize it. return compressing |
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* backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL) |
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* if requested algorithm is not supported, ERR_PTR(-ENOMEM) in |
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* case of allocation error, or any other error potentially |
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* returned by zcomp_init(). |
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*/ |
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struct zcomp *zcomp_create(const char *compress) |
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{ |
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struct zcomp *comp; |
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int error; |
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if (!zcomp_available_algorithm(compress)) |
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return ERR_PTR(-EINVAL); |
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comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL); |
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if (!comp) |
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return ERR_PTR(-ENOMEM); |
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comp->name = compress; |
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error = zcomp_init(comp); |
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if (error) { |
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kfree(comp); |
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return ERR_PTR(error); |
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} |
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return comp; |
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}
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