[PATCH] fs: ubifs: Add support for ZSTD decompression

[Piotr Wojtaszczyk]

ZSTD can be a better tradeoff between NAND IO operations and decompression
speed giving a better boot time.

Signed-off-by: Piotr Wojtaszczyk <piotr.wojtaszczyk at timesys.com>
---

 fs/ubifs/ubifs-media.h |  2 ++
 fs/ubifs/ubifs.c       | 53 ++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h
index 2b5b26a01b..299d80f928 100644
--- a/fs/ubifs/ubifs-media.h
+++ b/fs/ubifs/ubifs-media.h
@@ -320,12 +320,14 @@ enum {
  * UBIFS_COMPR_NONE: no compression
  * UBIFS_COMPR_LZO: LZO compression
  * UBIFS_COMPR_ZLIB: ZLIB compression
+ * UBIFS_COMPR_ZSTD: ZSTD compression
  * UBIFS_COMPR_TYPES_CNT: count of supported compression types
  */
 enum {
 	UBIFS_COMPR_NONE,
 	UBIFS_COMPR_LZO,
 	UBIFS_COMPR_ZLIB,
+	UBIFS_COMPR_ZSTD,
 	UBIFS_COMPR_TYPES_CNT,
 };
 
diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
index a509584e5d..ff3945e7fd 100644
--- a/fs/ubifs/ubifs.c
+++ b/fs/ubifs/ubifs.c
@@ -27,6 +27,11 @@
 #include <linux/err.h>
 #include <linux/lzo.h>
 
+#if IS_ENABLED(CONFIG_ZSTD)
+#include <linux/zstd.h>
+#include <abuf.h>
+#endif
+
 DECLARE_GLOBAL_DATA_PTR;
 
 /* compress.c */
@@ -42,6 +47,25 @@ static int gzip_decompress(const unsigned char *in, size_t in_len,
 		      (unsigned long *)out_len, 0, 0);
 }
 
+#if IS_ENABLED(CONFIG_ZSTD)
+static int zstd_decompress_wrapper(const unsigned char *in, size_t in_len,
+				   unsigned char *out, size_t *out_len)
+{
+	struct abuf abuf_in, abuf_out;
+	int ret;
+
+	abuf_init_set(&abuf_in, (void *)in, in_len);
+	abuf_init_set(&abuf_out, (void *)out, *out_len);
+
+	ret = zstd_decompress(&abuf_in, &abuf_out);
+	if (ret < 0)
+		return ret;
+
+	*out_len = ret;
+	return 0;
+}
+#endif
+
 /* Fake description object for the "none" compressor */
 static struct ubifs_compressor none_compr = {
 	.compr_type = UBIFS_COMPR_NONE,
@@ -71,8 +95,21 @@ static struct ubifs_compressor zlib_compr = {
 	.decompress = gzip_decompress,
 };
 
+#if IS_ENABLED(CONFIG_ZSTD)
+static struct ubifs_compressor zstd_compr = {
+	.compr_type = UBIFS_COMPR_ZSTD,
+#ifndef __UBOOT__
+	.comp_mutex = &zstd_enc_mutex,
+	.decomp_mutex = &zstd_dec_mutex,
+#endif
+	.name = "zstd",
+	.capi_name = "zstd",
+	.decompress = zstd_decompress_wrapper,
+};
+#endif
+
 /* All UBIFS compressors */
-struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
+struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT] = {NULL};
 
 
 #ifdef __UBOOT__
@@ -166,8 +203,14 @@ int ubifs_decompress(const struct ubifs_info *c, const void *in_buf,
 
 	compr = ubifs_compressors[compr_type];
 
+	if (unlikely(!compr)) {
+		ubifs_err(c, "compression type %d is not compiled in", compr_type);
+		return -EINVAL;
+	}
+
 	if (unlikely(!compr->capi_name)) {
-		ubifs_err(c, "%s compression is not compiled in", compr->name);
+		ubifs_err(c, "%s compression is not compiled in",
+			  compr->name ? compr->name : "unknown");
 		return -EINVAL;
 	}
 
@@ -232,6 +275,12 @@ int __init ubifs_compressors_init(void)
 	if (err)
 		return err;
 
+#if IS_ENABLED(CONFIG_ZSTD)
+	err = compr_init(&zstd_compr);
+	if (err)
+		return err;
+#endif
+
 	err = compr_init(&none_compr);
 	if (err)
 		return err;
-- 
2.25.1