fabrics: retry discovery log page when DNR is not set

Reading the discovery log page might result in an NVMe status,
so we should evaluate the DNR bit to check if it's safe to retry
the command.

Signed-off-by: Hannes Reinecke <[email protected]>

src/nvme/fabrics.c

@@ -1051,6 +1051,7 @@ static struct nvmf_discovery_log *nvme_discovery_log(
 	int retries = 0;
 	const char *name = nvme_ctrl_get_name(args->c);
 	uint64_t genctr, numrec;
+	__u32 result;
 	int fd = nvme_ctrl_get_fd(args->c);
 	struct nvme_get_log_args log_args = {
 		.result = args->result,
@@ -1076,13 +1077,21 @@ static struct nvmf_discovery_log *nvme_discovery_log(
 		 name, retries, args->max_retries);
 	log_args.log = log;
 	log_args.len = DISCOVERY_HEADER_LEN;
+	if (!args->result)
+		log_args.result = &result;
+retry_header:
 	if (nvme_get_log_page(fd, NVME_LOG_PAGE_PDU_SIZE, &log_args)) {
 		nvme_msg(r, LOG_INFO,
 			 "%s: discover try %d/%d failed, error %d\n",
 			 name, retries, args->max_retries, errno);
+		if (*log_args.result &&
+		    !(*log_args.result & NVME_SC_DNR) &&
+		    (++retries < args->max_retries))
+			goto retry_header;
 		goto out_free_log;
 	}
 
+	retries = 0;
 	do {
 		size_t entries_size;
 
@@ -1113,6 +1122,9 @@ static struct nvmf_discovery_log *nvme_discovery_log(
 			nvme_msg(r, LOG_INFO,
 				 "%s: discover try %d/%d failed, error %d\n",
 				 name, retries, args->max_retries, errno);
+			if (*log_args.result &&
+			    !(*log_args.result & NVME_SC_DNR))
+				continue;
 			goto out_free_log;
 		}
 
@@ -1129,6 +1141,9 @@ static struct nvmf_discovery_log *nvme_discovery_log(
 			nvme_msg(r, LOG_INFO,
 				 "%s: discover try %d/%d failed, error %d\n",
 				 name, retries, args->max_retries, errno);
+			if (*log_args.result &&
+			    !(*log_args.result & NVME_SC_DNR))
+				continue;
 			goto out_free_log;
 		}
 	} while (genctr != le64_to_cpu(log->genctr) &&