Initial import

1 files changed, 64 insertions, 0 deletions

diff --git a/lib/crc-t10dif.c b/lib/crc-t10dif.c
new file mode 100644
index 000000000..dfe6ec17c
--- /dev/null
+++ b/lib/crc-t10dif.c
@@ -0,0 +1,64 @@
+/*
+ * T10 Data Integrity Field CRC16 calculation
+ *
+ * Copyright (c) 2007 Oracle Corporation.  All rights reserved.
+ * Written by Martin K. Petersen <martin.petersen@oracle.com>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/crc-t10dif.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <crypto/hash.h>
+#include <linux/static_key.h>
+
+static struct crypto_shash *crct10dif_tfm;
+static struct static_key crct10dif_fallback __read_mostly;
+
+__u16 crc_t10dif(const unsigned char *buffer, size_t len)
+{
+	struct {
+		struct shash_desc shash;
+		char ctx[2];
+	} desc;
+	int err;
+
+	if (static_key_false(&crct10dif_fallback))
+		return crc_t10dif_generic(0, buffer, len);
+
+	desc.shash.tfm = crct10dif_tfm;
+	desc.shash.flags = 0;
+	*(__u16 *)desc.ctx = 0;
+
+	err = crypto_shash_update(&desc.shash, buffer, len);
+	BUG_ON(err);
+
+	return *(__u16 *)desc.ctx;
+}
+EXPORT_SYMBOL(crc_t10dif);
+
+static int __init crc_t10dif_mod_init(void)
+{
+	crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
+	if (IS_ERR(crct10dif_tfm)) {
+		static_key_slow_inc(&crct10dif_fallback);
+		crct10dif_tfm = NULL;
+	}
+	return 0;
+}
+
+static void __exit crc_t10dif_mod_fini(void)
+{
+	crypto_free_shash(crct10dif_tfm);
+}
+
+module_init(crc_t10dif_mod_init);
+module_exit(crc_t10dif_mod_fini);
+
+MODULE_DESCRIPTION("T10 DIF CRC calculation");
+MODULE_LICENSE("GPL");
+MODULE_SOFTDEP("pre: crct10dif");