[PATCH] fs/squashfs: enable LZ4 compression support

[David Oberhollenzer]

The structure is identical to the existing compressor implementations,
trivially adding lz4 decompression to sqfs_decompress.

The changes were tested using a sandbox build. An LZ4 compressed
squashfs image was bound as a host block device.

Signed-off-by: David Oberhollenzer <goliath at infraroot.at>
---
 fs/squashfs/sqfs_decompressor.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/fs/squashfs/sqfs_decompressor.c b/fs/squashfs/sqfs_decompressor.c
index 6b3e01cdad..cfd1153fd7 100644
--- a/fs/squashfs/sqfs_decompressor.c
+++ b/fs/squashfs/sqfs_decompressor.c
@@ -18,6 +18,10 @@
 #include <u-boot/zlib.h>
 #endif
 
+#if IS_ENABLED(CONFIG_LZ4)
+#include <u-boot/lz4.h>
+#endif
+
 #if IS_ENABLED(CONFIG_ZSTD)
 #include <linux/zstd.h>
 #endif
@@ -38,6 +42,10 @@ int sqfs_decompressor_init(struct squashfs_ctxt *ctxt)
 	case SQFS_COMP_ZLIB:
 		break;
 #endif
+#if IS_ENABLED(CONFIG_LZ4)
+	case SQFS_COMP_LZ4:
+		break;
+#endif
 #if IS_ENABLED(CONFIG_ZSTD)
 	case SQFS_COMP_ZSTD:
 		ctxt->zstd_workspace = malloc(zstd_dctx_workspace_bound());
@@ -66,6 +74,10 @@ void sqfs_decompressor_cleanup(struct squashfs_ctxt *ctxt)
 	case SQFS_COMP_ZLIB:
 		break;
 #endif
+#if IS_ENABLED(CONFIG_LZ4)
+	case SQFS_COMP_LZ4:
+		break;
+#endif
 #if IS_ENABLED(CONFIG_ZSTD)
 	case SQFS_COMP_ZSTD:
 		free(ctxt->zstd_workspace);
@@ -139,6 +151,17 @@ int sqfs_decompress(struct squashfs_ctxt *ctxt, void *dest,
 
 		break;
 #endif
+#if IS_ENABLED(CONFIG_LZ4)
+	case SQFS_COMP_LZ4:
+		ret = LZ4_decompress_safe(source, dest, src_len, *dest_len);
+		if (ret < 0) {
+			printf("LZ4 decompression failed.\n");
+			return -EINVAL;
+		}
+
+		ret = 0;
+		break;
+#endif
 #if IS_ENABLED(CONFIG_ZSTD)
 	case SQFS_COMP_ZSTD:
 		ret = sqfs_zstd_decompress(ctxt, dest, *dest_len, source, src_len);
-- 
2.41.0