fs/squashfs: add support for ZSTD decompression

Add call to ZSTD's ZSTD_decompressDCtx(). In this use case, the caller
can upper bound the decompressed size, which will be the SquashFS data
block (or metadata block) size, so there is no need to use streaming
API. Add ZSTD's worskpace to squashfs_ctxt structure.

Signed-off-by: Joao Marcos Costa <joaomarcos.costa@bootlin.com>

diff --git a/fs/squashfs/sqfs_decompressor.c b/fs/squashfs/sqfs_decompressor.c
index cf388ace587d512979b4660ecf35d51ba83dcce1..9457ee5f0f9894ea135e4a56c6de78417765199e 100644 (file)
--- a/fs/squashfs/sqfs_decompressor.c
+++ b/fs/squashfs/sqfs_decompressor.c
@@ -13,6 +13,10 @@
 #include <u-boot/zlib.h>
 #endif
 
+#if IS_ENABLED(CONFIG_ZSTD)
+#include <linux/zstd.h>
+#endif
+
 #include "sqfs_decompressor.h"
 #include "sqfs_utils.h"
 
@@ -24,6 +28,13 @@ int sqfs_decompressor_init(struct squashfs_ctxt *ctxt)
 #if IS_ENABLED(CONFIG_ZLIB)
        case SQFS_COMP_ZLIB:
                break;
+#endif
+#if IS_ENABLED(CONFIG_ZSTD)
+       case SQFS_COMP_ZSTD:
+               ctxt->zstd_workspace = malloc(ZSTD_DCtxWorkspaceBound());
+               if (!ctxt->zstd_workspace)
+                       return -ENOMEM;
+               break;
 #endif
        default:
                printf("Error: unknown compression type.\n");
@@ -41,6 +52,11 @@ void sqfs_decompressor_cleanup(struct squashfs_ctxt *ctxt)
 #if IS_ENABLED(CONFIG_ZLIB)
        case SQFS_COMP_ZLIB:
                break;
+#endif
+#if IS_ENABLED(CONFIG_ZSTD)
+       case SQFS_COMP_ZSTD:
+               free(ctxt->zstd_workspace);
+               break;
 #endif
        }
 }
@@ -62,6 +78,22 @@ static void zlib_decompression_status(int ret)
 }
 #endif
 
+#if IS_ENABLED(CONFIG_ZSTD)
+static int sqfs_zstd_decompress(struct squashfs_ctxt *ctxt, void *dest,
+                               unsigned long dest_len, void *source, u32 src_len)
+{
+       ZSTD_DCtx *ctx;
+       size_t wsize;
+       int ret;
+
+       wsize = ZSTD_DCtxWorkspaceBound();
+       ctx = ZSTD_initDCtx(ctxt->zstd_workspace, wsize);
+       ret = ZSTD_decompressDCtx(ctx, dest, dest_len, source, src_len);
+
+       return ZSTD_isError(ret);
+}
+#endif /* CONFIG_ZSTD */
+
 int sqfs_decompress(struct squashfs_ctxt *ctxt, void *dest,
                    unsigned long *dest_len, void *source, u32 src_len)
 {
@@ -79,6 +111,16 @@ int sqfs_decompress(struct squashfs_ctxt *ctxt, void *dest,
 
                break;
 #endif
+#if IS_ENABLED(CONFIG_ZSTD)
+       case SQFS_COMP_ZSTD:
+               ret = sqfs_zstd_decompress(ctxt, dest, *dest_len, source, src_len);
+               if (ret) {
+                       printf("ZSTD Error code: %d\n", ZSTD_getErrorCode(ret));
+                       return -EINVAL;
+               }
+
+               break;
+#endif
        default:
                printf("Error: unknown compression type.\n");
                return -EINVAL;

diff --git a/fs/squashfs/sqfs_filesystem.h b/fs/squashfs/sqfs_filesystem.h
index ff2b0b1d34eccb8a8536f695c22778fcd0ccde01..856cd15e349b710b70466f7a3f13b89afe1673c0 100644 (file)
--- a/fs/squashfs/sqfs_filesystem.h
+++ b/fs/squashfs/sqfs_filesystem.h
@@ -77,6 +77,9 @@ struct squashfs_ctxt {
        struct disk_partition cur_part_info;
        struct blk_desc *cur_dev;
        struct squashfs_super_block *sblk;
+#if IS_ENABLED(CONFIG_ZSTD)
+       void *zstd_workspace;
+#endif
 };
 
 struct squashfs_directory_index {