Now, contextless compression API is introduced and it can reduce
memory overhead in some cases. All compression algorithm will
support it.

Signed-off-by: Joonsoo Kim <iamjoonsoo....@lge.com>
---
 crypto/lz4.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 67 insertions(+), 10 deletions(-)

diff --git a/crypto/lz4.c b/crypto/lz4.c
index aefbcea..9720409 100644
--- a/crypto/lz4.c
+++ b/crypto/lz4.c
@@ -23,36 +23,53 @@
 #include <linux/crypto.h>
 #include <linux/vmalloc.h>
 #include <linux/lz4.h>
+#include <crypto/compress.h>
 
 struct lz4_ctx {
        void *lz4_comp_mem;
 };
 
+static void *lz4_alloc_context(struct crypto_ccomp *tfm)
+{
+       void *ctx;
+
+       ctx = vmalloc(LZ4_MEM_COMPRESS);
+       if (!ctx)
+               return ERR_PTR(-ENOMEM);
+
+       return ctx;
+}
+
 static int lz4_init(struct crypto_tfm *tfm)
 {
        struct lz4_ctx *ctx = crypto_tfm_ctx(tfm);
 
-       ctx->lz4_comp_mem = vmalloc(LZ4_MEM_COMPRESS);
-       if (!ctx->lz4_comp_mem)
+       ctx->lz4_comp_mem = lz4_alloc_context(NULL);
+       if (IS_ERR(ctx->lz4_comp_mem))
                return -ENOMEM;
 
        return 0;
 }
 
+static void lz4_free_context(struct crypto_ccomp *tfm, void *ctx)
+{
+       vfree(ctx);
+}
+
 static void lz4_exit(struct crypto_tfm *tfm)
 {
        struct lz4_ctx *ctx = crypto_tfm_ctx(tfm);
-       vfree(ctx->lz4_comp_mem);
+
+       lz4_free_context(NULL, ctx->lz4_comp_mem);
 }
 
-static int lz4_compress_crypto(struct crypto_tfm *tfm, const u8 *src,
-                           unsigned int slen, u8 *dst, unsigned int *dlen)
+static int __lz4_compress_crypto(const u8 *src, unsigned int slen,
+                               u8 *dst, unsigned int *dlen, void *ctx)
 {
-       struct lz4_ctx *ctx = crypto_tfm_ctx(tfm);
        size_t tmp_len = *dlen;
        int err;
 
-       err = lz4_compress(src, slen, dst, &tmp_len, ctx->lz4_comp_mem);
+       err = lz4_compress(src, slen, dst, &tmp_len, ctx);
 
        if (err < 0)
                return -EINVAL;
@@ -61,8 +78,16 @@ static int lz4_compress_crypto(struct crypto_tfm *tfm, const 
u8 *src,
        return 0;
 }
 
-static int lz4_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
-                             unsigned int slen, u8 *dst, unsigned int *dlen)
+static int lz4_compress_crypto(struct crypto_tfm *tfm, const u8 *src,
+                           unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+       struct lz4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+       return __lz4_compress_crypto(src, slen, dst, dlen, ctx->lz4_comp_mem);
+}
+
+static int __lz4_decompress_crypto(const u8 *src, unsigned int slen,
+                               u8 *dst, unsigned int *dlen, void *ctx)
 {
        int err;
        size_t tmp_len = *dlen;
@@ -76,6 +101,12 @@ static int lz4_decompress_crypto(struct crypto_tfm *tfm, 
const u8 *src,
        return err;
 }
 
+static int lz4_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
+                             unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+       return __lz4_decompress_crypto(src, slen, dst, dlen, NULL);
+}
+
 static struct crypto_alg alg_lz4 = {
        .cra_name               = "lz4",
        .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
@@ -89,14 +120,40 @@ static struct crypto_alg alg_lz4 = {
        .coa_decompress         = lz4_decompress_crypto } }
 };
 
+static struct ccomp_alg ccomp = {
+       .alloc_context          = lz4_alloc_context,
+       .free_context           = lz4_free_context,
+       .compress               = __lz4_compress_crypto,
+       .decompress             = __lz4_decompress_crypto,
+       .flags                  = CCOMP_TYPE_DECOMP_NOCTX,
+       .base                   = {
+               .cra_name       = "lz4",
+               .cra_flags      = CRYPTO_ALG_TYPE_CCOMPRESS,
+               .cra_module     = THIS_MODULE,
+       }
+};
+
 static int __init lz4_mod_init(void)
 {
-       return crypto_register_alg(&alg_lz4);
+       int ret;
+
+       ret = crypto_register_alg(&alg_lz4);
+       if (ret)
+               return ret;
+
+       ret = crypto_register_ccomp(&ccomp);
+       if (ret) {
+               crypto_unregister_alg(&alg_lz4);
+               return ret;
+       }
+
+       return ret;
 }
 
 static void __exit lz4_mod_fini(void)
 {
        crypto_unregister_alg(&alg_lz4);
+       crypto_unregister_ccomp(&ccomp);
 }
 
 module_init(lz4_mod_init);
-- 
1.9.1

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