Add scomp backend for 842 compression algorithm

Signed-off-by: Giovanni Cabiddu <giovanni.cabi...@intel.com>
---
 crypto/842.c   |  135 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 crypto/Kconfig |    1 +
 2 files changed, 134 insertions(+), 2 deletions(-)

diff --git a/crypto/842.c b/crypto/842.c
index 98e387e..d0894e2 100644
--- a/crypto/842.c
+++ b/crypto/842.c
@@ -30,12 +30,53 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/crypto.h>
+#include <crypto/scatterwalk.h>
 #include <linux/sw842.h>
+#include <crypto/internal/scompress.h>
+
+#define SW842_SCRATCH_SIZE     131072
 
 struct crypto842_ctx {
-       char wmem[SW842_MEM_COMPRESS];  /* working memory for compress */
+       void *wmem;     /* working memory for compress */
 };
 
+static void * __percpu *sw842_src_scratches;
+static void * __percpu *sw842_dst_scratches;
+
+static void *crypto842_alloc_ctx(struct crypto_scomp *tfm)
+{
+       void *ctx;
+
+       ctx = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
+       if (!ctx)
+               return ERR_PTR(-ENOMEM);
+
+       return ctx;
+}
+
+static int crypto842_init(struct crypto_tfm *tfm)
+{
+       struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
+
+       ctx->wmem = crypto842_alloc_ctx(NULL);
+       if (IS_ERR(ctx->wmem))
+               return -ENOMEM;
+
+       return 0;
+}
+
+static void crypto842_free_ctx(struct crypto_scomp *tfm, void *ctx)
+{
+       kfree(ctx);
+}
+
+static void crypto842_exit(struct crypto_tfm *tfm)
+{
+       struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
+
+       crypto842_free_ctx(NULL, ctx->wmem);
+}
+
 static int crypto842_compress(struct crypto_tfm *tfm,
                              const u8 *src, unsigned int slen,
                              u8 *dst, unsigned int *dlen)
@@ -52,6 +93,51 @@ static int crypto842_decompress(struct crypto_tfm *tfm,
        return sw842_decompress(src, slen, dst, dlen);
 }
 
+static int sw842_scomp_comp_decomp(struct crypto_scomp *tfm,
+                                  struct scatterlist *src, unsigned int slen,
+                                  struct scatterlist *dst, unsigned int *dlen,
+                                  void *ctx, int dir)
+{
+       const int cpu = get_cpu();
+       u8 *scratch_src = *per_cpu_ptr(sw842_src_scratches, cpu);
+       u8 *scratch_dst = *per_cpu_ptr(sw842_dst_scratches, cpu);
+       int ret;
+
+       if (slen > SW842_SCRATCH_SIZE || *dlen > SW842_SCRATCH_SIZE) {
+               ret = -EINVAL;
+               goto out;
+       }
+
+       scatterwalk_map_and_copy(scratch_src, src, 0, slen, 0);
+       if (dir)
+               ret = sw842_compress(scratch_src, slen, scratch_dst, dlen,
+                                    ctx);
+       else
+               ret = sw842_decompress(scratch_src, slen, scratch_dst, dlen);
+       if (!ret)
+               scatterwalk_map_and_copy(scratch_dst, dst, 0, *dlen, 1);
+
+out:
+       put_cpu();
+       return ret;
+}
+
+static int sw842_scomp_compress(struct crypto_scomp *tfm,
+                               struct scatterlist *src, unsigned int slen,
+                               struct scatterlist *dst, unsigned int *dlen,
+                               void *ctx)
+{
+       return sw842_scomp_comp_decomp(tfm, src, slen, dst, dlen, ctx, 1);
+}
+
+static int sw842_scomp_decompress(struct crypto_scomp *tfm,
+                                 struct scatterlist *src, unsigned int slen,
+                                 struct scatterlist *dst, unsigned int *dlen,
+                                 void *ctx)
+{
+       return sw842_scomp_comp_decomp(tfm, src, slen, dst, dlen, ctx, 0);
+}
+
 static struct crypto_alg alg = {
        .cra_name               = "842",
        .cra_driver_name        = "842-generic",
@@ -59,20 +145,65 @@ static struct crypto_alg alg = {
        .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
        .cra_ctxsize            = sizeof(struct crypto842_ctx),
        .cra_module             = THIS_MODULE,
+       .cra_init               = crypto842_init,
+       .cra_exit               = crypto842_exit,
        .cra_u                  = { .compress = {
        .coa_compress           = crypto842_compress,
        .coa_decompress         = crypto842_decompress } }
 };
 
+static struct scomp_alg scomp = {
+       .alloc_ctx              = crypto842_alloc_ctx,
+       .free_ctx               = crypto842_free_ctx,
+       .compress               = sw842_scomp_compress,
+       .decompress             = sw842_scomp_decompress,
+       .base                   = {
+               .cra_name       = "842",
+               .cra_driver_name = "842-scomp",
+               .cra_priority    = 100,
+               .cra_module      = THIS_MODULE,
+       }
+};
+
 static int __init crypto842_mod_init(void)
 {
-       return crypto_register_alg(&alg);
+       int ret;
+
+       sw842_src_scratches = crypto_scomp_alloc_scratches(SW842_SCRATCH_SIZE);
+       if (!sw842_src_scratches)
+               return -ENOMEM;
+
+       sw842_dst_scratches = crypto_scomp_alloc_scratches(SW842_SCRATCH_SIZE);
+       if (!sw842_dst_scratches) {
+               ret = -ENOMEM;
+               goto error;
+       }
+
+       ret = crypto_register_alg(&alg);
+       if (ret)
+               goto error;
+
+       ret = crypto_register_scomp(&scomp);
+       if (ret) {
+               crypto_unregister_alg(&alg);
+               goto error;
+       }
+
+       return ret;
+
+error:
+       crypto_scomp_free_scratches(sw842_src_scratches);
+       crypto_scomp_free_scratches(sw842_dst_scratches);
+       return ret;
 }
 module_init(crypto842_mod_init);
 
 static void __exit crypto842_mod_exit(void)
 {
        crypto_unregister_alg(&alg);
+       crypto_unregister_scomp(&scomp);
+       crypto_scomp_free_scratches(sw842_src_scratches);
+       crypto_scomp_free_scratches(sw842_dst_scratches);
 }
 module_exit(crypto842_mod_exit);
 
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 4258e85..ac7b519 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1598,6 +1598,7 @@ config CRYPTO_LZO
 config CRYPTO_842
        tristate "842 compression algorithm"
        select CRYPTO_ALGAPI
+       select CRYPTO_ACOMP2
        select 842_COMPRESS
        select 842_DECOMPRESS
        help
-- 
1.7.4.1

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