Add crc7 verify type

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/Makefile b/Makefile
index 05d735f..bf2e5c0 100644
--- a/Makefile
+++ b/Makefile
@@ -6,8 +6,8 @@
 PROGS	= fio
 SCRIPTS = fio_generate_plots
 OBJS = gettime.o fio.o ioengines.o init.o stat.o log.o time.o md5.o crc32.o \
-	crc16.o filesetup.o eta.o verify.o memory.o io_u.o parse.o mutex.o \
-	options.o rbtree.o diskutil.o fifo.o blktrace.o
+	crc16.o crc7.o filesetup.o eta.o verify.o memory.o io_u.o parse.o \
+	mutex.o options.o rbtree.o diskutil.o fifo.o blktrace.o
 
 OBJS += engines/cpu.o
 OBJS += engines/libaio.o
diff --git a/crc7.c b/crc7.c
new file mode 100644
index 0000000..47aa332
--- /dev/null
+++ b/crc7.c
@@ -0,0 +1,53 @@
+/*
+ *      crc7.c
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include "crc7.h"
+
+/* Table for CRC-7 (polynomial x^7 + x^3 + 1) */
+const unsigned char crc7_syndrome_table[256] = {
+	0x00, 0x09, 0x12, 0x1b, 0x24, 0x2d, 0x36, 0x3f,
+	0x48, 0x41, 0x5a, 0x53, 0x6c, 0x65, 0x7e, 0x77,
+	0x19, 0x10, 0x0b, 0x02, 0x3d, 0x34, 0x2f, 0x26,
+	0x51, 0x58, 0x43, 0x4a, 0x75, 0x7c, 0x67, 0x6e,
+	0x32, 0x3b, 0x20, 0x29, 0x16, 0x1f, 0x04, 0x0d,
+	0x7a, 0x73, 0x68, 0x61, 0x5e, 0x57, 0x4c, 0x45,
+	0x2b, 0x22, 0x39, 0x30, 0x0f, 0x06, 0x1d, 0x14,
+	0x63, 0x6a, 0x71, 0x78, 0x47, 0x4e, 0x55, 0x5c,
+	0x64, 0x6d, 0x76, 0x7f, 0x40, 0x49, 0x52, 0x5b,
+	0x2c, 0x25, 0x3e, 0x37, 0x08, 0x01, 0x1a, 0x13,
+	0x7d, 0x74, 0x6f, 0x66, 0x59, 0x50, 0x4b, 0x42,
+	0x35, 0x3c, 0x27, 0x2e, 0x11, 0x18, 0x03, 0x0a,
+	0x56, 0x5f, 0x44, 0x4d, 0x72, 0x7b, 0x60, 0x69,
+	0x1e, 0x17, 0x0c, 0x05, 0x3a, 0x33, 0x28, 0x21,
+	0x4f, 0x46, 0x5d, 0x54, 0x6b, 0x62, 0x79, 0x70,
+	0x07, 0x0e, 0x15, 0x1c, 0x23, 0x2a, 0x31, 0x38,
+	0x41, 0x48, 0x53, 0x5a, 0x65, 0x6c, 0x77, 0x7e,
+	0x09, 0x00, 0x1b, 0x12, 0x2d, 0x24, 0x3f, 0x36,
+	0x58, 0x51, 0x4a, 0x43, 0x7c, 0x75, 0x6e, 0x67,
+	0x10, 0x19, 0x02, 0x0b, 0x34, 0x3d, 0x26, 0x2f,
+	0x73, 0x7a, 0x61, 0x68, 0x57, 0x5e, 0x45, 0x4c,
+	0x3b, 0x32, 0x29, 0x20, 0x1f, 0x16, 0x0d, 0x04,
+	0x6a, 0x63, 0x78, 0x71, 0x4e, 0x47, 0x5c, 0x55,
+	0x22, 0x2b, 0x30, 0x39, 0x06, 0x0f, 0x14, 0x1d,
+	0x25, 0x2c, 0x37, 0x3e, 0x01, 0x08, 0x13, 0x1a,
+	0x6d, 0x64, 0x7f, 0x76, 0x49, 0x40, 0x5b, 0x52,
+	0x3c, 0x35, 0x2e, 0x27, 0x18, 0x11, 0x0a, 0x03,
+	0x74, 0x7d, 0x66, 0x6f, 0x50, 0x59, 0x42, 0x4b,
+	0x17, 0x1e, 0x05, 0x0c, 0x33, 0x3a, 0x21, 0x28,
+	0x5f, 0x56, 0x4d, 0x44, 0x7b, 0x72, 0x69, 0x60,
+	0x0e, 0x07, 0x1c, 0x15, 0x2a, 0x23, 0x38, 0x31,
+	0x46, 0x4f, 0x54, 0x5d, 0x62, 0x6b, 0x70, 0x79
+};
+
+unsigned char crc7(const unsigned char *buffer, unsigned int len)
+{
+	unsigned char crc = 0;
+
+	while (len--)
+		crc = crc7_byte(crc, *buffer++);
+	return crc;
+}
diff --git a/crc7.h b/crc7.h
new file mode 100644
index 0000000..6ff3cd8
--- /dev/null
+++ b/crc7.h
@@ -0,0 +1,13 @@
+#ifndef CRC7_H
+#define CRC7_H
+
+extern const unsigned char crc7_syndrome_table[256];
+
+static inline unsigned char crc7_byte(unsigned char crc, unsigned char data)
+{
+	return crc7_syndrome_table[(crc << 1) ^ data];
+}
+
+extern unsigned char crc7(const unsigned char *buffer, unsigned int len);
+
+#endif
diff --git a/fio.h b/fio.h
index fa3f568..63cfaa7 100644
--- a/fio.h
+++ b/fio.h
@@ -20,6 +20,7 @@
 #include "md5.h"
 #include "crc32.h"
 #include "crc16.h"
+#include "crc7.h"
 #include "arch/arch.h"
 #include "os/os.h"
 #include "mutex.h"
@@ -195,6 +196,7 @@
 	VERIFY_MD5,			/* md5 sum data blocks */
 	VERIFY_CRC32,			/* crc32 sum data blocks */
 	VERIFY_CRC16,			/* crc16 sum data blocks */
+	VERIFY_CRC7,			/* crc7 sum data blocks */
 	VERIFY_NULL,			/* pretend to verify */
 };
 
@@ -209,6 +211,7 @@
 		char md5_digest[MD5_HASH_WORDS * 4];
 		unsigned long crc32;
 		unsigned short crc16;
+		unsigned char crc7;
 	};
 };
 
diff --git a/options.c b/options.c
index cf42a6d..99996f9 100644
--- a/options.c
+++ b/options.c
@@ -577,6 +577,10 @@
 			    .oval = VERIFY_CRC16,
 			    .help = "Use crc16 checksums for verification",
 			  },
+			  { .ival = "crc7",
+			    .oval = VERIFY_CRC7,
+			    .help = "Use crc7 checksums for verification",
+			  },
 			  { .ival = "md5",
 			    .oval = VERIFY_MD5,
 			    .help = "Use md5 checksums for verification",
diff --git a/verify.c b/verify.c
index cca070c..492cc91 100644
--- a/verify.c
+++ b/verify.c
@@ -42,6 +42,23 @@
 	log_info("\n");
 }
 
+static int verify_io_u_crc7(struct verify_header *hdr, struct io_u *io_u)
+{
+	unsigned char *p = io_u->buf;
+	unsigned char c;
+
+	p += sizeof(*hdr);
+	c = crc7(p, hdr->len - sizeof(*hdr));
+
+	if (c != hdr->crc7) {
+		log_err("crc7: verify failed at %llu/%lu\n", io_u->offset, io_u->buflen);
+		log_err("crc7: wanted %x, got %x\n", hdr->crc7, c);
+		return 1;
+	}
+
+	return 0;
+}
+
 static int verify_io_u_crc16(struct verify_header *hdr, struct io_u *io_u)
 {
 	unsigned char *p = io_u->buf;
@@ -114,6 +131,8 @@
 		ret = verify_io_u_crc32(hdr, io_u);
 	else if (hdr->verify_type == VERIFY_CRC16)
 		ret = verify_io_u_crc16(hdr, io_u);
+	else if (hdr->verify_type == VERIFY_CRC7)
+		ret = verify_io_u_crc7(hdr, io_u);
 	else {
 		log_err("Bad verify type %u\n", hdr->verify_type);
 		ret = 1;
@@ -125,6 +144,11 @@
 	return 0;
 }
 
+static void fill_crc7(struct verify_header *hdr, void *p, unsigned int len)
+{
+	hdr->crc7 = crc7(p, len);
+}
+
 static void fill_crc16(struct verify_header *hdr, void *p, unsigned int len)
 {
 	hdr->crc16 = crc16(p, len);
@@ -170,6 +194,9 @@
 	} else if (td->o.verify == VERIFY_CRC16) {
 		fill_crc16(&hdr, p, io_u->buflen - sizeof(hdr));
 		hdr.verify_type = VERIFY_CRC16;
+	} else if (td->o.verify == VERIFY_CRC7) {
+		fill_crc7(&hdr, p, io_u->buflen - sizeof(hdr));
+		hdr.verify_type = VERIFY_CRC7;
 	}
 
 	memcpy(io_u->buf, &hdr, sizeof(hdr));