Merge tag 'pstore-v4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore update from Kees Cook:
 "This cycle has been very quiet for pstore: the only change is adding
  awareness of the zstd compression method"

* tag 'pstore-v4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore: add zstd compression support

2 files changed, 30 insertions, 3 deletions

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 09c19ef91526..503086f7f7c1 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -50,12 +50,19 @@ config PSTORE_842_COMPRESS
         help
           This option enables 842 compression algorithm support.
 
+config PSTORE_ZSTD_COMPRESS
+        bool "zstd compression"
+        depends on PSTORE
+        select CRYPTO_ZSTD
+        help
+          This option enables zstd compression algorithm support.
+
 config PSTORE_COMPRESS
         def_bool y
         depends on PSTORE
         depends on PSTORE_DEFLATE_COMPRESS || PSTORE_LZO_COMPRESS ||    \
                    PSTORE_LZ4_COMPRESS || PSTORE_LZ4HC_COMPRESS ||      \
-                   PSTORE_842_COMPRESS
+                   PSTORE_842_COMPRESS || PSTORE_ZSTD_COMPRESS
 
 choice
         prompt "Default pstore compression algorithm"
@@ -65,8 +72,8 @@ choice
           This change be changed at boot with "pstore.compress=..." on
           the kernel command line.
 
-          Currently, pstore has support for 5 compression algorithms:
-          deflate, lzo, lz4, lz4hc and 842.
+          Currently, pstore has support for 6 compression algorithms:
+          deflate, lzo, lz4, lz4hc, 842 and zstd.
 
           The default compression algorithm is deflate.
 
@@ -85,6 +92,9 @@ choice
         config PSTORE_842_COMPRESS_DEFAULT
                 bool "842" if PSTORE_842_COMPRESS
 
+        config PSTORE_ZSTD_COMPRESS_DEFAULT
+                bool "zstd" if PSTORE_ZSTD_COMPRESS
+
 endchoice
 
 config PSTORE_COMPRESS_DEFAULT
@@ -95,6 +105,7 @@ config PSTORE_COMPRESS_DEFAULT
         default "lz4" if PSTORE_LZ4_COMPRESS_DEFAULT
         default "lz4hc" if PSTORE_LZ4HC_COMPRESS_DEFAULT
         default "842" if PSTORE_842_COMPRESS_DEFAULT
+        default "zstd" if PSTORE_ZSTD_COMPRESS_DEFAULT
 
 config PSTORE_CONSOLE
         bool "Log kernel console messages"
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index c238ab8ba31d..15e99d5a681d 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -34,6 +34,9 @@
 #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
 #include <linux/lz4.h>
 #endif
+#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
+#include <linux/zstd.h>
+#endif
 #include <linux/crypto.h>
 #include <linux/string.h>
 #include <linux/timer.h>
@@ -192,6 +195,13 @@ static int zbufsize_842(size_t size)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
+static int zbufsize_zstd(size_t size)
+{
+        return ZSTD_compressBound(size);
+}
+#endif
+
 static const struct pstore_zbackend *zbackend __ro_after_init;
 
 static const struct pstore_zbackend zbackends[] = {
@@ -225,6 +235,12 @@ static const struct pstore_zbackend zbackends[] = {
                 .name           = "842",
         },
 #endif
+#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
+        {
+                .zbufsize       = zbufsize_zstd,
+                .name           = "zstd",
+        },
+#endif
         { }
 };