Re: [PATCH] pstore: add lz4hc and 842 compression support

[Geliang Tang]

On Tue, Nov 28, 2017 at 05:44:52PM -0800, Kees Cook wrote:
> > +
> > +   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
> > +   if (!ret) {
> > +   pr_err("LZ4_compress_default error; compression failed!\n");
> > +   return -EIO;
> > +   }
> > +
> > +   return ret;
> 
> Other compress/decompress return outlen, rather than ret. Is "ret" the
> outlen here?
> 

> > +
> > +   ret = LZ4_compress_HC(in, out, inlen, outlen,
> > + LZ4HC_DEFAULT_CLEVEL, workspace);
> > +   if (!ret) {
> > +   pr_err("LZ4_compress_HC error; compression failed!\n");
> > +   return -EIO;
> > +   }
> > +
> > +   return ret;
> 
> And here?
> 

Yes, ret is outlen in LZ4_compress_default and LZ4_compress_HC.

> > +
> > +   ret = sw842_compress(in, inlen, out, , workspace);
> > +   if (!ret) {
> > +   pr_err("sw842_compress error; compression failed!\n");
> > +   return -EIO;
> > +   }
> > +   outlen = len;
> 
> This has no effect. What was intended?
> 

> > +   ret = sw842_decompress(in, inlen, out, );
> > +   if (ret < 0) {
> > +   pr_err("sw842_decompress error, ret = %d!\n", ret);
> > +   return -EIO;
> > +   }
> > +   outlen = len;
> 
> Same.
> 

I fixed them in patch v3.

> 
> Otherwise this all looks good. Thanks!
> 
> -Kees
> 
> -- 
> Kees Cook
> Pixel Security

Geliang Tang (1):
  pstore: add lz4hc and 842 compression support

 fs/pstore/Kconfig|  25 +
 fs/pstore/platform.c | 147 ---
 2 files changed, 154 insertions(+), 18 deletions(-)

-- 
2.14.1

Re: [PATCH] pstore: add lz4hc and 842 compression support

[Geliang Tang]

On Tue, Nov 28, 2017 at 05:44:52PM -0800, Kees Cook wrote:
> > +
> > +   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
> > +   if (!ret) {
> > +   pr_err("LZ4_compress_default error; compression failed!\n");
> > +   return -EIO;
> > +   }
> > +
> > +   return ret;
> 
> Other compress/decompress return outlen, rather than ret. Is "ret" the
> outlen here?
> 

> > +
> > +   ret = LZ4_compress_HC(in, out, inlen, outlen,
> > + LZ4HC_DEFAULT_CLEVEL, workspace);
> > +   if (!ret) {
> > +   pr_err("LZ4_compress_HC error; compression failed!\n");
> > +   return -EIO;
> > +   }
> > +
> > +   return ret;
> 
> And here?
> 

Yes, ret is outlen in LZ4_compress_default and LZ4_compress_HC.

> > +
> > +   ret = sw842_compress(in, inlen, out, , workspace);
> > +   if (!ret) {
> > +   pr_err("sw842_compress error; compression failed!\n");
> > +   return -EIO;
> > +   }
> > +   outlen = len;
> 
> This has no effect. What was intended?
> 

> > +   ret = sw842_decompress(in, inlen, out, );
> > +   if (ret < 0) {
> > +   pr_err("sw842_decompress error, ret = %d!\n", ret);
> > +   return -EIO;
> > +   }
> > +   outlen = len;
> 
> Same.
> 

I fixed them in patch v3.

> 
> Otherwise this all looks good. Thanks!
> 
> -Kees
> 
> -- 
> Kees Cook
> Pixel Security

Geliang Tang (1):
  pstore: add lz4hc and 842 compression support

 fs/pstore/Kconfig|  25 +
 fs/pstore/platform.c | 147 ---
 2 files changed, 154 insertions(+), 18 deletions(-)

-- 
2.14.1

Re: [PATCH] pstore: add lz4hc and 842 compression support

[Kees Cook]

Sorry for the delay on this review!

On Mon, Aug 28, 2017 at 6:56 AM, Geliang Tang  wrote:
> Currently, pstore has supported three compression algorithms: zlib,
> lzo and lz4. This patch added two more compression algorithms: lz4hc
> and 842.
>
> Signed-off-by: Geliang Tang 
> ---
>  fs/pstore/Kconfig|  14 ++
>  fs/pstore/platform.c | 128 
> +--
>  2 files changed, 127 insertions(+), 15 deletions(-)
>
> diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
> index b42e5bd..e288596 100644
> --- a/fs/pstore/Kconfig
> +++ b/fs/pstore/Kconfig
> @@ -39,6 +39,20 @@ config PSTORE_LZ4_COMPRESS
>  select LZ4_DECOMPRESS
>  help
>This option enables LZ4 compression algorithm support.
> +
> +config PSTORE_LZ4HC_COMPRESS
> +   bool "LZ4HC"
> +   select LZ4HC_COMPRESS
> +   select LZ4_DECOMPRESS
> +   help
> + This option enables LZ4 high compression mode algorithm.
> +
> +config PSTORE_842_COMPRESS
> +   bool "842"
> +   select 842_COMPRESS
> +   select 842_DECOMPRESS
> +   help
> + This option enables 842 compression algorithm support.
>  endchoice

I'm fine with these short descriptions. checkpatch's warning for
"choice" options doesn't always make sense. :)

>
>  config PSTORE_CONSOLE
> diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
> index 2b21d18..252c320 100644
> --- a/fs/pstore/platform.c
> +++ b/fs/pstore/platform.c
> @@ -34,9 +34,12 @@
>  #ifdef CONFIG_PSTORE_LZO_COMPRESS
>  #include 
>  #endif
> -#ifdef CONFIG_PSTORE_LZ4_COMPRESS
> +#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
> defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
>  #include 
>  #endif
> +#ifdef CONFIG_PSTORE_842_COMPRESS
> +#include 
> +#endif
>  #include 
>  #include 
>  #include 
> @@ -337,20 +340,7 @@ static const struct pstore_zbackend backend_lzo = {
>  };
>  #endif
>
> -#ifdef CONFIG_PSTORE_LZ4_COMPRESS
> -static int compress_lz4(const void *in, void *out, size_t inlen, size_t 
> outlen)
> -{
> -   int ret;
> -
> -   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
> -   if (!ret) {
> -   pr_err("LZ4_compress_default error; compression failed!\n");
> -   return -EIO;
> -   }
> -
> -   return ret;
> -}
> -
> +#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
> defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
>  static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
>  {
> int ret;
> @@ -392,6 +382,21 @@ static void free_lz4(void)
> big_oops_buf = NULL;
> big_oops_buf_sz = 0;
>  }
> +#endif
> +
> +#ifdef CONFIG_PSTORE_LZ4_COMPRESS
> +static int compress_lz4(const void *in, void *out, size_t inlen, size_t 
> outlen)
> +{
> +   int ret;
> +
> +   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
> +   if (!ret) {
> +   pr_err("LZ4_compress_default error; compression failed!\n");
> +   return -EIO;
> +   }
> +
> +   return ret;

Other compress/decompress return outlen, rather than ret. Is "ret" the
outlen here?

> +}
>
>  static const struct pstore_zbackend backend_lz4 = {
> .compress   = compress_lz4,
> @@ -402,6 +407,95 @@ static const struct pstore_zbackend backend_lz4 = {
>  };
>  #endif
>
> +#ifdef CONFIG_PSTORE_LZ4HC_COMPRESS
> +static int compress_lz4hc(const void *in, void *out,
> + size_t inlen, size_t outlen)
> +{
> +   int ret;
> +
> +   ret = LZ4_compress_HC(in, out, inlen, outlen,
> + LZ4HC_DEFAULT_CLEVEL, workspace);
> +   if (!ret) {
> +   pr_err("LZ4_compress_HC error; compression failed!\n");
> +   return -EIO;
> +   }
> +
> +   return ret;

And here?

> +}
> +
> +static const struct pstore_zbackend backend_lz4hc = {
> +   .compress   = compress_lz4hc,
> +   .decompress = decompress_lz4,
> +   .allocate   = allocate_lz4,
> +   .free   = free_lz4,
> +   .name   = "lz4hc",
> +};
> +#endif
> +
> +#ifdef CONFIG_PSTORE_842_COMPRESS
> +static int compress_842(const void *in, void *out, size_t inlen, size_t 
> outlen)
> +{
> +   int ret;
> +   unsigned int len;
> +
> +   ret = sw842_compress(in, inlen, out, , workspace);
> +   if (!ret) {
> +   pr_err("sw842_compress error; compression failed!\n");
> +   return -EIO;
> +   }
> +   outlen = len;

This has no effect. What was intended?

> +
> +   return ret;
> +}
> +
> +static int decompress_842(void *in, void *out, size_t inlen, size_t outlen)
> +{
> +   int ret;
> +   unsigned int len;
> +
> +   ret = sw842_decompress(in, inlen, out, );
> +   if (ret < 0) {
> +   pr_err("sw842_decompress error, ret = %d!\n", ret);
> +   return -EIO;
> +   }
> +   outlen = len;

Same.

> +
> +   return ret;
> +}
> +
> +static void 

Re: [PATCH] pstore: add lz4hc and 842 compression support

[Kees Cook]

Sorry for the delay on this review!

On Mon, Aug 28, 2017 at 6:56 AM, Geliang Tang  wrote:
> Currently, pstore has supported three compression algorithms: zlib,
> lzo and lz4. This patch added two more compression algorithms: lz4hc
> and 842.
>
> Signed-off-by: Geliang Tang 
> ---
>  fs/pstore/Kconfig|  14 ++
>  fs/pstore/platform.c | 128 
> +--
>  2 files changed, 127 insertions(+), 15 deletions(-)
>
> diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
> index b42e5bd..e288596 100644
> --- a/fs/pstore/Kconfig
> +++ b/fs/pstore/Kconfig
> @@ -39,6 +39,20 @@ config PSTORE_LZ4_COMPRESS
>  select LZ4_DECOMPRESS
>  help
>This option enables LZ4 compression algorithm support.
> +
> +config PSTORE_LZ4HC_COMPRESS
> +   bool "LZ4HC"
> +   select LZ4HC_COMPRESS
> +   select LZ4_DECOMPRESS
> +   help
> + This option enables LZ4 high compression mode algorithm.
> +
> +config PSTORE_842_COMPRESS
> +   bool "842"
> +   select 842_COMPRESS
> +   select 842_DECOMPRESS
> +   help
> + This option enables 842 compression algorithm support.
>  endchoice

I'm fine with these short descriptions. checkpatch's warning for
"choice" options doesn't always make sense. :)

>
>  config PSTORE_CONSOLE
> diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
> index 2b21d18..252c320 100644
> --- a/fs/pstore/platform.c
> +++ b/fs/pstore/platform.c
> @@ -34,9 +34,12 @@
>  #ifdef CONFIG_PSTORE_LZO_COMPRESS
>  #include 
>  #endif
> -#ifdef CONFIG_PSTORE_LZ4_COMPRESS
> +#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
> defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
>  #include 
>  #endif
> +#ifdef CONFIG_PSTORE_842_COMPRESS
> +#include 
> +#endif
>  #include 
>  #include 
>  #include 
> @@ -337,20 +340,7 @@ static const struct pstore_zbackend backend_lzo = {
>  };
>  #endif
>
> -#ifdef CONFIG_PSTORE_LZ4_COMPRESS
> -static int compress_lz4(const void *in, void *out, size_t inlen, size_t 
> outlen)
> -{
> -   int ret;
> -
> -   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
> -   if (!ret) {
> -   pr_err("LZ4_compress_default error; compression failed!\n");
> -   return -EIO;
> -   }
> -
> -   return ret;
> -}
> -
> +#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
> defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
>  static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
>  {
> int ret;
> @@ -392,6 +382,21 @@ static void free_lz4(void)
> big_oops_buf = NULL;
> big_oops_buf_sz = 0;
>  }
> +#endif
> +
> +#ifdef CONFIG_PSTORE_LZ4_COMPRESS
> +static int compress_lz4(const void *in, void *out, size_t inlen, size_t 
> outlen)
> +{
> +   int ret;
> +
> +   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
> +   if (!ret) {
> +   pr_err("LZ4_compress_default error; compression failed!\n");
> +   return -EIO;
> +   }
> +
> +   return ret;

Other compress/decompress return outlen, rather than ret. Is "ret" the
outlen here?

> +}
>
>  static const struct pstore_zbackend backend_lz4 = {
> .compress   = compress_lz4,
> @@ -402,6 +407,95 @@ static const struct pstore_zbackend backend_lz4 = {
>  };
>  #endif
>
> +#ifdef CONFIG_PSTORE_LZ4HC_COMPRESS
> +static int compress_lz4hc(const void *in, void *out,
> + size_t inlen, size_t outlen)
> +{
> +   int ret;
> +
> +   ret = LZ4_compress_HC(in, out, inlen, outlen,
> + LZ4HC_DEFAULT_CLEVEL, workspace);
> +   if (!ret) {
> +   pr_err("LZ4_compress_HC error; compression failed!\n");
> +   return -EIO;
> +   }
> +
> +   return ret;

And here?

> +}
> +
> +static const struct pstore_zbackend backend_lz4hc = {
> +   .compress   = compress_lz4hc,
> +   .decompress = decompress_lz4,
> +   .allocate   = allocate_lz4,
> +   .free   = free_lz4,
> +   .name   = "lz4hc",
> +};
> +#endif
> +
> +#ifdef CONFIG_PSTORE_842_COMPRESS
> +static int compress_842(const void *in, void *out, size_t inlen, size_t 
> outlen)
> +{
> +   int ret;
> +   unsigned int len;
> +
> +   ret = sw842_compress(in, inlen, out, , workspace);
> +   if (!ret) {
> +   pr_err("sw842_compress error; compression failed!\n");
> +   return -EIO;
> +   }
> +   outlen = len;

This has no effect. What was intended?

> +
> +   return ret;
> +}
> +
> +static int decompress_842(void *in, void *out, size_t inlen, size_t outlen)
> +{
> +   int ret;
> +   unsigned int len;
> +
> +   ret = sw842_decompress(in, inlen, out, );
> +   if (ret < 0) {
> +   pr_err("sw842_decompress error, ret = %d!\n", ret);
> +   return -EIO;
> +   }
> +   outlen = len;

Same.

> +
> +   return ret;
> +}
> +
> +static void allocate_842(void)
> +{
> +   big_oops_buf_sz 

[PATCH] pstore: add lz4hc and 842 compression support

[Geliang Tang]

Currently, pstore has supported three compression algorithms: zlib,
lzo and lz4. This patch added two more compression algorithms: lz4hc
and 842.

Signed-off-by: Geliang Tang 
---
 fs/pstore/Kconfig|  14 ++
 fs/pstore/platform.c | 128 +--
 2 files changed, 127 insertions(+), 15 deletions(-)

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index b42e5bd..e288596 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -39,6 +39,20 @@ config PSTORE_LZ4_COMPRESS
 select LZ4_DECOMPRESS
 help
   This option enables LZ4 compression algorithm support.
+
+config PSTORE_LZ4HC_COMPRESS
+   bool "LZ4HC"
+   select LZ4HC_COMPRESS
+   select LZ4_DECOMPRESS
+   help
+ This option enables LZ4 high compression mode algorithm.
+
+config PSTORE_842_COMPRESS
+   bool "842"
+   select 842_COMPRESS
+   select 842_DECOMPRESS
+   help
+ This option enables 842 compression algorithm support.
 endchoice
 
 config PSTORE_CONSOLE
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 2b21d18..252c320 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -34,9 +34,12 @@
 #ifdef CONFIG_PSTORE_LZO_COMPRESS
 #include 
 #endif
-#ifdef CONFIG_PSTORE_LZ4_COMPRESS
+#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
 #include 
 #endif
+#ifdef CONFIG_PSTORE_842_COMPRESS
+#include 
+#endif
 #include 
 #include 
 #include 
@@ -337,20 +340,7 @@ static const struct pstore_zbackend backend_lzo = {
 };
 #endif
 
-#ifdef CONFIG_PSTORE_LZ4_COMPRESS
-static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
-{
-   int ret;
-
-   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
-   if (!ret) {
-   pr_err("LZ4_compress_default error; compression failed!\n");
-   return -EIO;
-   }
-
-   return ret;
-}
-
+#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
 static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
 {
int ret;
@@ -392,6 +382,21 @@ static void free_lz4(void)
big_oops_buf = NULL;
big_oops_buf_sz = 0;
 }
+#endif
+
+#ifdef CONFIG_PSTORE_LZ4_COMPRESS
+static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
+{
+   int ret;
+
+   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
+   if (!ret) {
+   pr_err("LZ4_compress_default error; compression failed!\n");
+   return -EIO;
+   }
+
+   return ret;
+}
 
 static const struct pstore_zbackend backend_lz4 = {
.compress   = compress_lz4,
@@ -402,6 +407,95 @@ static const struct pstore_zbackend backend_lz4 = {
 };
 #endif
 
+#ifdef CONFIG_PSTORE_LZ4HC_COMPRESS
+static int compress_lz4hc(const void *in, void *out,
+ size_t inlen, size_t outlen)
+{
+   int ret;
+
+   ret = LZ4_compress_HC(in, out, inlen, outlen,
+ LZ4HC_DEFAULT_CLEVEL, workspace);
+   if (!ret) {
+   pr_err("LZ4_compress_HC error; compression failed!\n");
+   return -EIO;
+   }
+
+   return ret;
+}
+
+static const struct pstore_zbackend backend_lz4hc = {
+   .compress   = compress_lz4hc,
+   .decompress = decompress_lz4,
+   .allocate   = allocate_lz4,
+   .free   = free_lz4,
+   .name   = "lz4hc",
+};
+#endif
+
+#ifdef CONFIG_PSTORE_842_COMPRESS
+static int compress_842(const void *in, void *out, size_t inlen, size_t outlen)
+{
+   int ret;
+   unsigned int len;
+
+   ret = sw842_compress(in, inlen, out, , workspace);
+   if (!ret) {
+   pr_err("sw842_compress error; compression failed!\n");
+   return -EIO;
+   }
+   outlen = len;
+
+   return ret;
+}
+
+static int decompress_842(void *in, void *out, size_t inlen, size_t outlen)
+{
+   int ret;
+   unsigned int len;
+
+   ret = sw842_decompress(in, inlen, out, );
+   if (ret < 0) {
+   pr_err("sw842_decompress error, ret = %d!\n", ret);
+   return -EIO;
+   }
+   outlen = len;
+
+   return ret;
+}
+
+static void allocate_842(void)
+{
+   big_oops_buf_sz = psinfo->bufsize * 2;
+   big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
+   if (big_oops_buf) {
+   workspace = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
+   if (!workspace) {
+   kfree(big_oops_buf);
+   big_oops_buf = NULL;
+   }
+   } else {
+   pr_err("No memory for uncompressed data; skipping 
compression\n");
+   workspace = NULL;
+   }
+}
+
+static void free_842(void)
+{
+   kfree(workspace);
+   kfree(big_oops_buf);
+   big_oops_buf = NULL;
+   big_oops_buf_sz = 0;
+}
+
+static const struct 

[PATCH] pstore: add lz4hc and 842 compression support

[Geliang Tang]

Currently, pstore has supported three compression algorithms: zlib,
lzo and lz4. This patch added two more compression algorithms: lz4hc
and 842.

Signed-off-by: Geliang Tang 
---
 fs/pstore/Kconfig|  14 ++
 fs/pstore/platform.c | 128 +--
 2 files changed, 127 insertions(+), 15 deletions(-)

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index b42e5bd..e288596 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -39,6 +39,20 @@ config PSTORE_LZ4_COMPRESS
 select LZ4_DECOMPRESS
 help
   This option enables LZ4 compression algorithm support.
+
+config PSTORE_LZ4HC_COMPRESS
+   bool "LZ4HC"
+   select LZ4HC_COMPRESS
+   select LZ4_DECOMPRESS
+   help
+ This option enables LZ4 high compression mode algorithm.
+
+config PSTORE_842_COMPRESS
+   bool "842"
+   select 842_COMPRESS
+   select 842_DECOMPRESS
+   help
+ This option enables 842 compression algorithm support.
 endchoice
 
 config PSTORE_CONSOLE
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 2b21d18..252c320 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -34,9 +34,12 @@
 #ifdef CONFIG_PSTORE_LZO_COMPRESS
 #include 
 #endif
-#ifdef CONFIG_PSTORE_LZ4_COMPRESS
+#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
 #include 
 #endif
+#ifdef CONFIG_PSTORE_842_COMPRESS
+#include 
+#endif
 #include 
 #include 
 #include 
@@ -337,20 +340,7 @@ static const struct pstore_zbackend backend_lzo = {
 };
 #endif
 
-#ifdef CONFIG_PSTORE_LZ4_COMPRESS
-static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
-{
-   int ret;
-
-   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
-   if (!ret) {
-   pr_err("LZ4_compress_default error; compression failed!\n");
-   return -EIO;
-   }
-
-   return ret;
-}
-
+#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || 
defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
 static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
 {
int ret;
@@ -392,6 +382,21 @@ static void free_lz4(void)
big_oops_buf = NULL;
big_oops_buf_sz = 0;
 }
+#endif
+
+#ifdef CONFIG_PSTORE_LZ4_COMPRESS
+static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
+{
+   int ret;
+
+   ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
+   if (!ret) {
+   pr_err("LZ4_compress_default error; compression failed!\n");
+   return -EIO;
+   }
+
+   return ret;
+}
 
 static const struct pstore_zbackend backend_lz4 = {
.compress   = compress_lz4,
@@ -402,6 +407,95 @@ static const struct pstore_zbackend backend_lz4 = {
 };
 #endif
 
+#ifdef CONFIG_PSTORE_LZ4HC_COMPRESS
+static int compress_lz4hc(const void *in, void *out,
+ size_t inlen, size_t outlen)
+{
+   int ret;
+
+   ret = LZ4_compress_HC(in, out, inlen, outlen,
+ LZ4HC_DEFAULT_CLEVEL, workspace);
+   if (!ret) {
+   pr_err("LZ4_compress_HC error; compression failed!\n");
+   return -EIO;
+   }
+
+   return ret;
+}
+
+static const struct pstore_zbackend backend_lz4hc = {
+   .compress   = compress_lz4hc,
+   .decompress = decompress_lz4,
+   .allocate   = allocate_lz4,
+   .free   = free_lz4,
+   .name   = "lz4hc",
+};
+#endif
+
+#ifdef CONFIG_PSTORE_842_COMPRESS
+static int compress_842(const void *in, void *out, size_t inlen, size_t outlen)
+{
+   int ret;
+   unsigned int len;
+
+   ret = sw842_compress(in, inlen, out, , workspace);
+   if (!ret) {
+   pr_err("sw842_compress error; compression failed!\n");
+   return -EIO;
+   }
+   outlen = len;
+
+   return ret;
+}
+
+static int decompress_842(void *in, void *out, size_t inlen, size_t outlen)
+{
+   int ret;
+   unsigned int len;
+
+   ret = sw842_decompress(in, inlen, out, );
+   if (ret < 0) {
+   pr_err("sw842_decompress error, ret = %d!\n", ret);
+   return -EIO;
+   }
+   outlen = len;
+
+   return ret;
+}
+
+static void allocate_842(void)
+{
+   big_oops_buf_sz = psinfo->bufsize * 2;
+   big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
+   if (big_oops_buf) {
+   workspace = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
+   if (!workspace) {
+   kfree(big_oops_buf);
+   big_oops_buf = NULL;
+   }
+   } else {
+   pr_err("No memory for uncompressed data; skipping 
compression\n");
+   workspace = NULL;
+   }
+}
+
+static void free_842(void)
+{
+   kfree(workspace);
+   kfree(big_oops_buf);
+   big_oops_buf = NULL;
+   big_oops_buf_sz = 0;
+}
+
+static const struct pstore_zbackend backend_842 = {
+