nbft: Add SSNS 'unavailable' flag

Certain pre-OS driver implementations (i.e. UEFI) may opt
to include SSNS records that failed to connect, caused either
by a temporary target inaccessibility or an invalid
configuration. Such reason is further indicated by TP8029
extended information.

This commit adds a flag indicating namespace availability
so that clients (nvme-cli) may either decide to skip such
record or make another connection attempt.

Signed-off-by: Tomas Bzatek <[email protected]>

src/nvme/nbft.c

@@ -246,6 +246,10 @@ static int read_ssns(struct nbft_info *nbft,
 	ssns->nid_type = raw_ssns->nidt;
 	ssns->nid = raw_ssns->nid;
 
+	/* flags */
+	ssns->unavailable = !!(le16_to_cpu(raw_ssns->flags) &
+			       NBFT_SSNS_UNAVAIL_NAMESPACE_UNAVAIL);
+
 	/* security profile */
 	if (raw_ssns->security_desc_index) {
 		ssns->security = security_from_index(nbft, raw_ssns->security_desc_index);

src/nvme/nbft.h

@@ -1180,6 +1180,8 @@ enum nbft_info_nid_type {
  * 				Descriptor) or 0 if not supported.
  * @dhcp_root_path_string:	DHCP Root Path Override string (SSNS Extended
  * 				Information Descriptor).
+ * @unavailable:		Namespace is unavailable as indicated by
+ * 				the pre-OS driver.
  */
 struct nbft_info_subsystem_ns {
 	int index;
@@ -1200,6 +1202,7 @@ struct nbft_info_subsystem_ns {
 	int controller_id;
 	int asqsz;
 	char *dhcp_root_path_string;
+	bool unavailable;
 };
 
 /**