util: add spdk_mem_all_zero() function

Unify several similar functions checking for a buffer of all zero bytes
into the util library.

Change-Id: Idfbeffa22add34ac9ed1bd75ee27d6bd8b188940
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/400892
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

app/nvmf_tgt/nvmf_rpc.c

@@ -39,23 +39,10 @@
 #include "spdk/env.h"
 #include "spdk/nvme.h"
 #include "spdk/nvmf.h"
+#include "spdk/string.h"
 #include "spdk/util.h"
 
 #include "nvmf_tgt.h"
-
-static bool
-all_zero(const void *data, size_t size)
-{
-	const uint8_t *buf = data;
-
-	while (size--) {
-		if (*buf++ != 0) {
-			return false;
-		}
-	}
-	return true;
-}
-
 static int
 json_write_hex_str(struct spdk_json_write_ctx *w, const void *data, size_t size)
 {
@@ -267,12 +254,12 @@ dump_nvmf_subsystem(struct spdk_json_write_ctx *w, struct spdk_nvmf_subsystem *s
 			spdk_json_write_name(w, "name");
 			spdk_json_write_string(w, spdk_bdev_get_name(spdk_nvmf_ns_get_bdev(ns)));
 
-			if (!all_zero(ns_opts.nguid, sizeof(ns_opts.nguid))) {
+			if (!spdk_mem_all_zero(ns_opts.nguid, sizeof(ns_opts.nguid))) {
 				spdk_json_write_name(w, "nguid");
 				json_write_hex_str(w, ns_opts.nguid, sizeof(ns_opts.nguid));
 			}
 
-			if (!all_zero(ns_opts.eui64, sizeof(ns_opts.eui64))) {
+			if (!spdk_mem_all_zero(ns_opts.eui64, sizeof(ns_opts.eui64))) {
 				spdk_json_write_name(w, "eui64");
 				json_write_hex_str(w, ns_opts.eui64, sizeof(ns_opts.eui64));
 			}

examples/nvme/identify/identify.c

@@ -40,6 +40,7 @@
 #include "spdk/nvme_intel.h"
 #include "spdk/nvmf_spec.h"
 #include "spdk/pci_ids.h"
+#include "spdk/string.h"
 #include "spdk/util.h"
 
 #define MAX_DISCOVERY_LOG_ENTRIES	((uint64_t)1000)
@@ -127,19 +128,6 @@ hex_dump(const void *data, size_t size)
 	}
 }
 
-static bool
-all_zero(const void *data, size_t size)
-{
-	const uint8_t *buf = data;
-
-	while (size--) {
-		if (*buf++ != 0) {
-			return false;
-		}
-	}
-	return true;
-}
-
 static void
 get_feature_completion(void *cb_arg, const struct spdk_nvme_cpl *cpl)
 {
@@ -521,12 +509,12 @@ print_namespace(struct spdk_nvme_ns *ns)
 	if (nsdata->noiob) {
 		printf("Optimal I/O Boundary:        %u blocks\n", nsdata->noiob);
 	}
-	if (!all_zero(nsdata->nguid, sizeof(nsdata->nguid))) {
+	if (!spdk_mem_all_zero(nsdata->nguid, sizeof(nsdata->nguid))) {
 		printf("NGUID:                       ");
 		print_hex_be(nsdata->nguid, sizeof(nsdata->nguid));
 		printf("\n");
 	}
-	if (!all_zero(&nsdata->eui64, sizeof(nsdata->eui64))) {
+	if (!spdk_mem_all_zero(&nsdata->eui64, sizeof(nsdata->eui64))) {
 		printf("EUI64:                       ");
 		print_hex_be(&nsdata->eui64, sizeof(nsdata->eui64));
 		printf("\n");

include/spdk/string.h

@@ -171,6 +171,15 @@ int spdk_parse_ip_addr(char *ip, char **host, char **port);
  */
 int spdk_parse_capacity(const char *cap_str, uint64_t *cap, bool *has_prefix);
 
+/**
+ * Check if a buffer is all zero (0x00) bytes or not.
+ *
+ * \param data Buffer to check.
+ * \param size Size of data in bytes.
+ * \return true if data consists entirely of zeroes, or false if any byte in data is not zero.
+ */
+bool spdk_mem_all_zero(const void *data, size_t size);
+
 #ifdef __cplusplus
 }
 #endif

lib/nvme/nvme_ctrlr.c

@@ -36,6 +36,7 @@
 #include "nvme_internal.h"
 
 #include "spdk/env.h"
+#include "spdk/string.h"
 
 #include <uuid/uuid.h>
 
@@ -934,10 +935,8 @@ static int
 nvme_ctrlr_set_host_id(struct spdk_nvme_ctrlr *ctrlr)
 {
 	struct nvme_completion_poll_status status;
-	bool all_zeroes;
 	uint8_t *host_id;
 	uint32_t host_id_size;
-	uint32_t i;
 	int rc;
 
 	if (ctrlr->trid.trtype != SPDK_NVME_TRANSPORT_PCIE) {
@@ -960,15 +959,7 @@ nvme_ctrlr_set_host_id(struct spdk_nvme_ctrlr *ctrlr)
 	}
 
 	/* If the user specified an all-zeroes host identifier, don't send the command. */
-	all_zeroes = true;
-	for (i = 0; i < host_id_size; i++) {
-		if (host_id[i] != 0) {
-			all_zeroes = false;
-			break;
-		}
-	}
-
-	if (all_zeroes) {
+	if (spdk_mem_all_zero(host_id, host_id_size)) {
 		SPDK_DEBUGLOG(SPDK_LOG_NVME,
 			      "User did not specify host ID - not sending Set Features - Host ID\n");
 		return 0;

lib/util/string.c

@@ -390,3 +390,17 @@ spdk_parse_capacity(const char *cap_str, uint64_t *cap, bool *has_prefix)
 
 	return 0;
 }
+
+bool
+spdk_mem_all_zero(const void *data, size_t size)
+{
+	const uint8_t *buf = data;
+
+	while (size--) {
+		if (*buf++ != 0) {
+			return false;
+		}
+	}
+
+	return true;
+}

test/unit/lib/nvmf/ctrlr_discovery.c/ctrlr_discovery_ut.c

@@ -174,21 +174,6 @@ spdk_nvmf_poll_group_resume_subsystem(struct spdk_nvmf_poll_group *group,
 	return 0;
 }
 
-static bool
-all_zero(const void *buf, size_t size)
-{
-	const uint8_t *b = buf;
-
-	while (size--) {
-		if (*b != 0) {
-			return false;
-		}
-		b++;
-	}
-
-	return true;
-}
-
 static void
 test_discovery_log(void)
 {
@@ -239,8 +224,8 @@ test_discovery_log(void)
 	CU_ASSERT(disc_log->genctr != 0);
 	CU_ASSERT(disc_log->numrec == 1);
 	CU_ASSERT(disc_log->entries[0].trtype == 42);
-	CU_ASSERT(all_zero(buffer + sizeof(*disc_log) + sizeof(disc_log->entries[0]),
-			   sizeof(buffer) - (sizeof(*disc_log) + sizeof(disc_log->entries[0]))));
+	CU_ASSERT(spdk_mem_all_zero(buffer + sizeof(*disc_log) + sizeof(disc_log->entries[0]),
+				    sizeof(buffer) - (sizeof(*disc_log) + sizeof(disc_log->entries[0]))));
 
 	/* Get just the first entry, no header */
 	memset(buffer, 0xCC, sizeof(buffer));