Initial import

1 files changed, 197 insertions, 0 deletions

diff --git a/block/t10-pi.c b/block/t10-pi.c
new file mode 100644
index 000000000..24d6e9715
--- /dev/null
+++ b/block/t10-pi.c
@@ -0,0 +1,197 @@
+/*
+ * t10_pi.c - Functions for generating and verifying T10 Protection
+ *	      Information.
+ *
+ * Copyright (C) 2007, 2008, 2014 Oracle Corporation
+ * Written by: Martin K. Petersen <martin.petersen@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
+ * USA.
+ *
+ */
+
+#include <linux/t10-pi.h>
+#include <linux/blkdev.h>
+#include <linux/crc-t10dif.h>
+#include <net/checksum.h>
+
+typedef __be16 (csum_fn) (void *, unsigned int);
+
+static const __be16 APP_ESCAPE = (__force __be16) 0xffff;
+static const __be32 REF_ESCAPE = (__force __be32) 0xffffffff;
+
+static __be16 t10_pi_crc_fn(void *data, unsigned int len)
+{
+	return cpu_to_be16(crc_t10dif(data, len));
+}
+
+static __be16 t10_pi_ip_fn(void *data, unsigned int len)
+{
+	return (__force __be16)ip_compute_csum(data, len);
+}
+
+/*
+ * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
+ * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
+ * tag.
+ */
+static int t10_pi_generate(struct blk_integrity_iter *iter, csum_fn *fn,
+			   unsigned int type)
+{
+	unsigned int i;
+
+	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
+		struct t10_pi_tuple *pi = iter->prot_buf;
+
+		pi->guard_tag = fn(iter->data_buf, iter->interval);
+		pi->app_tag = 0;
+
+		if (type == 1)
+			pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
+		else
+			pi->ref_tag = 0;
+
+		iter->data_buf += iter->interval;
+		iter->prot_buf += sizeof(struct t10_pi_tuple);
+		iter->seed++;
+	}
+
+	return 0;
+}
+
+static int t10_pi_verify(struct blk_integrity_iter *iter, csum_fn *fn,
+				unsigned int type)
+{
+	unsigned int i;
+
+	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
+		struct t10_pi_tuple *pi = iter->prot_buf;
+		__be16 csum;
+
+		switch (type) {
+		case 1:
+		case 2:
+			if (pi->app_tag == APP_ESCAPE)
+				goto next;
+
+			if (be32_to_cpu(pi->ref_tag) !=
+			    lower_32_bits(iter->seed)) {
+				pr_err("%s: ref tag error at location %llu " \
+				       "(rcvd %u)\n", iter->disk_name,
+				       (unsigned long long)
+				       iter->seed, be32_to_cpu(pi->ref_tag));
+				return -EILSEQ;
+			}
+			break;
+		case 3:
+			if (pi->app_tag == APP_ESCAPE &&
+			    pi->ref_tag == REF_ESCAPE)
+				goto next;
+			break;
+		}
+
+		csum = fn(iter->data_buf, iter->interval);
+
+		if (pi->guard_tag != csum) {
+			pr_err("%s: guard tag error at sector %llu " \
+			       "(rcvd %04x, want %04x)\n", iter->disk_name,
+			       (unsigned long long)iter->seed,
+			       be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
+			return -EILSEQ;
+		}
+
+next:
+		iter->data_buf += iter->interval;
+		iter->prot_buf += sizeof(struct t10_pi_tuple);
+		iter->seed++;
+	}
+
+	return 0;
+}
+
+static int t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
+{
+	return t10_pi_generate(iter, t10_pi_crc_fn, 1);
+}
+
+static int t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
+{
+	return t10_pi_generate(iter, t10_pi_ip_fn, 1);
+}
+
+static int t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
+{
+	return t10_pi_verify(iter, t10_pi_crc_fn, 1);
+}
+
+static int t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
+{
+	return t10_pi_verify(iter, t10_pi_ip_fn, 1);
+}
+
+static int t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
+{
+	return t10_pi_generate(iter, t10_pi_crc_fn, 3);
+}
+
+static int t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
+{
+	return t10_pi_generate(iter, t10_pi_ip_fn, 3);
+}
+
+static int t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
+{
+	return t10_pi_verify(iter, t10_pi_crc_fn, 3);
+}
+
+static int t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
+{
+	return t10_pi_verify(iter, t10_pi_ip_fn, 3);
+}
+
+struct blk_integrity t10_pi_type1_crc = {
+	.name			= "T10-DIF-TYPE1-CRC",
+	.generate_fn		= t10_pi_type1_generate_crc,
+	.verify_fn		= t10_pi_type1_verify_crc,
+	.tuple_size		= sizeof(struct t10_pi_tuple),
+	.tag_size		= 0,
+};
+EXPORT_SYMBOL(t10_pi_type1_crc);
+
+struct blk_integrity t10_pi_type1_ip = {
+	.name			= "T10-DIF-TYPE1-IP",
+	.generate_fn		= t10_pi_type1_generate_ip,
+	.verify_fn		= t10_pi_type1_verify_ip,
+	.tuple_size		= sizeof(struct t10_pi_tuple),
+	.tag_size		= 0,
+};
+EXPORT_SYMBOL(t10_pi_type1_ip);
+
+struct blk_integrity t10_pi_type3_crc = {
+	.name			= "T10-DIF-TYPE3-CRC",
+	.generate_fn		= t10_pi_type3_generate_crc,
+	.verify_fn		= t10_pi_type3_verify_crc,
+	.tuple_size		= sizeof(struct t10_pi_tuple),
+	.tag_size		= 0,
+};
+EXPORT_SYMBOL(t10_pi_type3_crc);
+
+struct blk_integrity t10_pi_type3_ip = {
+	.name			= "T10-DIF-TYPE3-IP",
+	.generate_fn		= t10_pi_type3_generate_ip,
+	.verify_fn		= t10_pi_type3_verify_ip,
+	.tuple_size		= sizeof(struct t10_pi_tuple),
+	.tag_size		= 0,
+};
+EXPORT_SYMBOL(t10_pi_type3_ip);