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-rw-r--r--kernel/fs/btrfs/hash.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/kernel/fs/btrfs/hash.c b/kernel/fs/btrfs/hash.c
new file mode 100644
index 000000000..aae520b2a
--- /dev/null
+++ b/kernel/fs/btrfs/hash.c
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <crypto/hash.h>
+#include <linux/err.h>
+#include "hash.h"
+
+static struct crypto_shash *tfm;
+
+int __init btrfs_hash_init(void)
+{
+ tfm = crypto_alloc_shash("crc32c", 0, 0);
+
+ return PTR_ERR_OR_ZERO(tfm);
+}
+
+void btrfs_hash_exit(void)
+{
+ crypto_free_shash(tfm);
+}
+
+u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length)
+{
+ SHASH_DESC_ON_STACK(shash, tfm);
+ u32 *ctx = (u32 *)shash_desc_ctx(shash);
+ int err;
+
+ shash->tfm = tfm;
+ shash->flags = 0;
+ *ctx = crc;
+
+ err = crypto_shash_update(shash, address, length);
+ BUG_ON(err);
+
+ return *ctx;
+}