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![Waiman Long](/assets/img/avatar_default.png)
As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
258 lines
5 KiB
C
258 lines
5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Cryptographic API.
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*
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* Copyright (c) 2017-present, Facebook, Inc.
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*/
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#include <linux/crypto.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/vmalloc.h>
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#include <linux/zstd.h>
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#include <crypto/internal/scompress.h>
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#define ZSTD_DEF_LEVEL 3
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struct zstd_ctx {
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ZSTD_CCtx *cctx;
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ZSTD_DCtx *dctx;
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void *cwksp;
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void *dwksp;
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};
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static ZSTD_parameters zstd_params(void)
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{
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return ZSTD_getParams(ZSTD_DEF_LEVEL, 0, 0);
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}
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static int zstd_comp_init(struct zstd_ctx *ctx)
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{
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int ret = 0;
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const ZSTD_parameters params = zstd_params();
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const size_t wksp_size = ZSTD_CCtxWorkspaceBound(params.cParams);
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ctx->cwksp = vzalloc(wksp_size);
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if (!ctx->cwksp) {
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ret = -ENOMEM;
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goto out;
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}
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ctx->cctx = ZSTD_initCCtx(ctx->cwksp, wksp_size);
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if (!ctx->cctx) {
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ret = -EINVAL;
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goto out_free;
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}
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out:
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return ret;
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out_free:
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vfree(ctx->cwksp);
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goto out;
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}
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static int zstd_decomp_init(struct zstd_ctx *ctx)
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{
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int ret = 0;
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const size_t wksp_size = ZSTD_DCtxWorkspaceBound();
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ctx->dwksp = vzalloc(wksp_size);
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if (!ctx->dwksp) {
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ret = -ENOMEM;
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goto out;
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}
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ctx->dctx = ZSTD_initDCtx(ctx->dwksp, wksp_size);
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if (!ctx->dctx) {
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ret = -EINVAL;
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goto out_free;
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}
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out:
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return ret;
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out_free:
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vfree(ctx->dwksp);
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goto out;
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}
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static void zstd_comp_exit(struct zstd_ctx *ctx)
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{
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vfree(ctx->cwksp);
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ctx->cwksp = NULL;
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ctx->cctx = NULL;
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}
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static void zstd_decomp_exit(struct zstd_ctx *ctx)
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{
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vfree(ctx->dwksp);
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ctx->dwksp = NULL;
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ctx->dctx = NULL;
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}
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static int __zstd_init(void *ctx)
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{
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int ret;
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ret = zstd_comp_init(ctx);
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if (ret)
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return ret;
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ret = zstd_decomp_init(ctx);
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if (ret)
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zstd_comp_exit(ctx);
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return ret;
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}
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static void *zstd_alloc_ctx(struct crypto_scomp *tfm)
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{
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int ret;
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struct zstd_ctx *ctx;
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ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return ERR_PTR(-ENOMEM);
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ret = __zstd_init(ctx);
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if (ret) {
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kfree(ctx);
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return ERR_PTR(ret);
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}
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return ctx;
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}
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static int zstd_init(struct crypto_tfm *tfm)
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{
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struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
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return __zstd_init(ctx);
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}
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static void __zstd_exit(void *ctx)
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{
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zstd_comp_exit(ctx);
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zstd_decomp_exit(ctx);
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}
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static void zstd_free_ctx(struct crypto_scomp *tfm, void *ctx)
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{
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__zstd_exit(ctx);
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kfree_sensitive(ctx);
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}
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static void zstd_exit(struct crypto_tfm *tfm)
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{
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struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
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__zstd_exit(ctx);
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}
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static int __zstd_compress(const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen, void *ctx)
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{
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size_t out_len;
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struct zstd_ctx *zctx = ctx;
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const ZSTD_parameters params = zstd_params();
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out_len = ZSTD_compressCCtx(zctx->cctx, dst, *dlen, src, slen, params);
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if (ZSTD_isError(out_len))
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return -EINVAL;
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*dlen = out_len;
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return 0;
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}
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static int zstd_compress(struct crypto_tfm *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen)
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{
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struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
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return __zstd_compress(src, slen, dst, dlen, ctx);
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}
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static int zstd_scompress(struct crypto_scomp *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen,
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void *ctx)
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{
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return __zstd_compress(src, slen, dst, dlen, ctx);
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}
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static int __zstd_decompress(const u8 *src, unsigned int slen,
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u8 *dst, unsigned int *dlen, void *ctx)
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{
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size_t out_len;
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struct zstd_ctx *zctx = ctx;
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out_len = ZSTD_decompressDCtx(zctx->dctx, dst, *dlen, src, slen);
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if (ZSTD_isError(out_len))
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return -EINVAL;
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*dlen = out_len;
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return 0;
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}
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static int zstd_decompress(struct crypto_tfm *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen)
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{
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struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
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return __zstd_decompress(src, slen, dst, dlen, ctx);
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}
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static int zstd_sdecompress(struct crypto_scomp *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen,
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void *ctx)
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{
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return __zstd_decompress(src, slen, dst, dlen, ctx);
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}
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static struct crypto_alg alg = {
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.cra_name = "zstd",
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.cra_driver_name = "zstd-generic",
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.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
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.cra_ctxsize = sizeof(struct zstd_ctx),
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.cra_module = THIS_MODULE,
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.cra_init = zstd_init,
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.cra_exit = zstd_exit,
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.cra_u = { .compress = {
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.coa_compress = zstd_compress,
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.coa_decompress = zstd_decompress } }
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};
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static struct scomp_alg scomp = {
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.alloc_ctx = zstd_alloc_ctx,
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.free_ctx = zstd_free_ctx,
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.compress = zstd_scompress,
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.decompress = zstd_sdecompress,
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.base = {
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.cra_name = "zstd",
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.cra_driver_name = "zstd-scomp",
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.cra_module = THIS_MODULE,
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}
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};
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static int __init zstd_mod_init(void)
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{
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int ret;
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ret = crypto_register_alg(&alg);
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if (ret)
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return ret;
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ret = crypto_register_scomp(&scomp);
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if (ret)
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crypto_unregister_alg(&alg);
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return ret;
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}
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static void __exit zstd_mod_fini(void)
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{
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crypto_unregister_alg(&alg);
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crypto_unregister_scomp(&scomp);
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}
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subsys_initcall(zstd_mod_init);
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module_exit(zstd_mod_fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Zstd Compression Algorithm");
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MODULE_ALIAS_CRYPTO("zstd");
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