util/crc16: Add init_crc parameter as seed value to spdk_crc16_t10dif

Add init_crc parameter as seed value to spdk_crc16_t10dif API to generate
a CRC value spanning multiple separate buffers.

This will be necessary for upcoming DIF/DIX patches.

Having init_crc parameter is general, and so change the existing API
without adding seed version of the existing API.

Change-Id: I0ac7919b18013967e41829dcedd3e4e73204d5d6
Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/437204
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

CHANGELOG.md

@@ -6,6 +6,10 @@
 
 A new uuid API `spdk_uuid_copy` was added to make a copy of the source uuid.
 
+An new parameter `init_crc` representing the initial CRC value was added to
+`spdk_crc16_t10dif`. The parameter can be used to calculate a CRC value spanning
+multiple separate buffers.
+
 ### nvme
 
 admin_timeout_ms was added to NVMe controller initialization options, users

examples/nvme/fio_plugin/fio_plugin.c

@@ -564,7 +564,7 @@ fio_extended_lba_setup_pi(struct spdk_fio_qpair *fio_qpair, struct io_u *io_u)
 		if (io_u->ddir == DDIR_WRITE) {
 			if (fio_qpair->io_flags & SPDK_NVME_IO_FLAGS_PRCHK_GUARD) {
 				/* CRC buffer should not include PI */
-				crc16 = spdk_crc16_t10dif(io_u->buf + extended_lba_size * i,
+				crc16 = spdk_crc16_t10dif(0, io_u->buf + extended_lba_size * i,
 							  extended_lba_size - 8);
 				to_be16(&pi->guard, crc16);
 			}
@@ -601,7 +601,7 @@ fio_extended_lba_verify_pi(struct spdk_fio_qpair *fio_qpair, struct io_u *io_u)
 
 		if (fio_qpair->io_flags & SPDK_NVME_IO_FLAGS_PRCHK_GUARD) {
 			/* CRC buffer should not include last 8 bytes of PI */
-			crc16 = spdk_crc16_t10dif(io_u->buf + extended_lba_size * i,
+			crc16 = spdk_crc16_t10dif(0, io_u->buf + extended_lba_size * i,
 						  extended_lba_size - 8);
 			to_be16(&guard, crc16);
 			if (pi->guard != guard) {

examples/nvme/perf/perf.c

@@ -541,7 +541,7 @@ task_extended_lba_setup_pi(struct ns_entry *entry, struct perf_task *task, uint6
 		if (is_write) {
 			if (entry->io_flags & SPDK_NVME_IO_FLAGS_PRCHK_GUARD) {
 				/* CRC buffer should not include PI */
-				crc16 = spdk_crc16_t10dif(task->buf + (sector_size + md_size) * i,
+				crc16 = spdk_crc16_t10dif(0, task->buf + (sector_size + md_size) * i,
 							  sector_size + md_size - 8);
 				to_be16(&pi->guard, crc16);
 			}
@@ -585,7 +585,7 @@ task_extended_lba_pi_verify(struct ns_entry *entry, struct perf_task *task,
 
 		if (entry->io_flags & SPDK_NVME_IO_FLAGS_PRCHK_GUARD) {
 			/* CRC buffer should not include last 8 bytes of PI */
-			crc16 = spdk_crc16_t10dif(task->buf + (sector_size + md_size) * i,
+			crc16 = spdk_crc16_t10dif(0, task->buf + (sector_size + md_size) * i,
 						  sector_size + md_size - 8);
 			to_be16(&guard, crc16);
 			if (pi->guard != guard) {

include/spdk/crc16.h

@@ -53,12 +53,12 @@ extern "C" {
 /**
  * Calculate T10-DIF CRC-16 checksum.
  *
+ * \param init_crc Initial CRC-16 value.
  * \param buf Data buffer to checksum.
  * \param len Length of buf in bytes.
  * \return CRC-16 value.
  */
-uint16_t spdk_crc16_t10dif(const void *buf, size_t len);
+uint16_t spdk_crc16_t10dif(uint16_t init_crc, const void *buf, size_t len);
-
 #ifdef __cplusplus
 }
 #endif

lib/util/crc16.c

@@ -34,14 +34,16 @@
 #include "spdk/crc16.h"
 
 uint16_t
-spdk_crc16_t10dif(const void *buf, size_t len)
+spdk_crc16_t10dif(uint16_t init_crc, const void *buf, size_t len)
 {
-	uint32_t j, rem = 0;
+	uint32_t j, rem;
 	const uint8_t *data = (const uint8_t *)buf;
 	size_t i;
 
 	uint16_t poly = SPDK_T10DIF_CRC16_POLYNOMIAL;
 
+	rem = init_crc;
+
 	for (i = 0; i < len; i++) {
 		rem = rem ^ (data[i] << 8);
 		for (j = 0; j < 8; j++) {

test/nvme/e2edp/nvme_dp.c

@@ -154,10 +154,10 @@ static uint32_t dp_guard_check_extended_lba_test(struct spdk_nvme_ns *ns, struct
 	ns_data_buffer_reset(ns, req, DATA_PATTERN);
 	pi = (struct spdk_nvme_protection_info *)(req->contig + sector_size + md_size - 8);
 	/* big-endian for guard */
-	to_be16(&pi->guard, spdk_crc16_t10dif(req->contig, sector_size));
+	to_be16(&pi->guard, spdk_crc16_t10dif(0, req->contig, sector_size));
 
 	pi = (struct spdk_nvme_protection_info *)(req->contig + (sector_size + md_size) * 2 - 8);
-	to_be16(&pi->guard, spdk_crc16_t10dif(req->contig + sector_size + md_size, sector_size));
+	to_be16(&pi->guard, spdk_crc16_t10dif(0, req->contig + sector_size + md_size, sector_size));
 
 	*io_flags = SPDK_NVME_IO_FLAGS_PRCHK_GUARD;
 

test/unit/lib/util/crc16.c/crc16_ut.c

@@ -43,7 +43,19 @@ test_crc16_t10dif(void)
 	uint16_t crc;
 	char buf[] = "123456789";
 
-	crc = spdk_crc16_t10dif(buf, strlen(buf));
+	crc = spdk_crc16_t10dif(0, buf, strlen(buf));
+	CU_ASSERT(crc == 0xd0db);
+}
+
+static void
+test_crc16_t10dif_seed(void)
+{
+	uint16_t crc = 0;
+	char buf1[] = "1234";
+	char buf2[] = "56789";
+
+	crc = spdk_crc16_t10dif(crc, buf1, strlen(buf1));
+	crc = spdk_crc16_t10dif(crc, buf2, strlen(buf2));
 	CU_ASSERT(crc == 0xd0db);
 }
 
@@ -64,7 +76,8 @@ main(int argc, char **argv)
 	}
 
 	if (
-		CU_add_test(suite, "test_crc16_t10dif", test_crc16_t10dif) == NULL) {
+		CU_add_test(suite, "test_crc16_t10dif", test_crc16_t10dif) == NULL ||
+		CU_add_test(suite, "test_crc16_t10dif_seed", test_crc16_t10dif_seed) == NULL) {
 		CU_cleanup_registry();
 		return CU_get_error();
 	}