nvme updates for Linux 5.16

- support the current discovery subsystem entry (Hannes Reinecke)
  - use flex_array_size and struct_size (Len Baker)
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Merge tag 'nvme-5.16-2021-10-28' of git://git.infradead.org/nvme into for-5.16/drivers

Pull NVMe updates from Christoph:

"nvme updates for Linux 5.16

 - support the current discovery subsystem entry (Hannes Reinecke)
 - use flex_array_size and struct_size (Len Baker)"

* tag 'nvme-5.16-2021-10-28' of git://git.infradead.org/nvme:
  nvmet: use flex_array_size and struct_size
  nvmet: register discovery subsystem as 'current'
  nvmet: switch check for subsystem type
  nvme: add new discovery log page entry definitions

drivers/nvme/host/multipath.c

@@ -562,7 +562,7 @@ static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
 			return -EINVAL;
 
 		nr_nsids = le32_to_cpu(desc->nnsids);
-		nsid_buf_size = nr_nsids * sizeof(__le32);
+		nsid_buf_size = flex_array_size(desc, nsids, nr_nsids);
 
 		if (WARN_ON_ONCE(desc->grpid == 0))
 			return -EINVAL;

drivers/nvme/target/admin-cmd.c

@@ -264,7 +264,7 @@ static u32 nvmet_format_ana_group(struct nvmet_req *req, u32 grpid,
 	desc->chgcnt = cpu_to_le64(nvmet_ana_chgcnt);
 	desc->state = req->port->ana_state[grpid];
 	memset(desc->rsvd17, 0, sizeof(desc->rsvd17));
-	return sizeof(struct nvme_ana_group_desc) + count * sizeof(__le32);
+	return struct_size(desc, nsids, count);
 }
 
 static void nvmet_execute_get_log_page_ana(struct nvmet_req *req)

drivers/nvme/target/core.c

@@ -1541,6 +1541,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 		subsys->max_qid = NVMET_NR_QUEUES;
 		break;
 	case NVME_NQN_DISC:
+	case NVME_NQN_CURR:
 		subsys->max_qid = 0;
 		break;
 	default:

drivers/nvme/target/discovery.c

@@ -146,7 +146,7 @@ static size_t discovery_log_entries(struct nvmet_req *req)
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvmet_subsys_link *p;
 	struct nvmet_port *r;
-	size_t entries = 0;
+	size_t entries = 1;
 
 	list_for_each_entry(p, &req->port->subsystems, entry) {
 		if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
@@ -171,6 +171,7 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
 	u32 numrec = 0;
 	u16 status = 0;
 	void *buffer;
+	char traddr[NVMF_TRADDR_SIZE];
 
 	if (!nvmet_check_transfer_len(req, data_len))
 		return;
@@ -203,15 +204,19 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
 		status = NVME_SC_INTERNAL;
 		goto out;
 	}
-
 	hdr = buffer;
-	list_for_each_entry(p, &req->port->subsystems, entry) {
-		char traddr[NVMF_TRADDR_SIZE];
 
+	nvmet_set_disc_traddr(req, req->port, traddr);
+
+	nvmet_format_discovery_entry(hdr, req->port,
+				     nvmet_disc_subsys->subsysnqn,
+				     traddr, NVME_NQN_CURR, numrec);
+	numrec++;
+
+	list_for_each_entry(p, &req->port->subsystems, entry) {
 		if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
 			continue;
 
-		nvmet_set_disc_traddr(req, req->port, traddr);
 		nvmet_format_discovery_entry(hdr, req->port,
 				p->subsys->subsysnqn, traddr,
 				NVME_NQN_NVME, numrec);
@@ -389,7 +394,7 @@ u16 nvmet_parse_discovery_cmd(struct nvmet_req *req)
 int __init nvmet_init_discovery(void)
 {
 	nvmet_disc_subsys =
-		nvmet_subsys_alloc(NVME_DISC_SUBSYS_NAME, NVME_NQN_DISC);
+		nvmet_subsys_alloc(NVME_DISC_SUBSYS_NAME, NVME_NQN_CURR);
 	return PTR_ERR_OR_ZERO(nvmet_disc_subsys);
 }
 

drivers/nvme/target/nvmet.h

@@ -579,7 +579,7 @@ static inline struct nvmet_subsys *nvmet_req_subsys(struct nvmet_req *req)
 
 static inline bool nvmet_is_disc_subsys(struct nvmet_subsys *subsys)
 {
-    return subsys->type == NVME_NQN_DISC;
+    return subsys->type != NVME_NQN_NVME;
 }
 
 #ifdef CONFIG_NVME_TARGET_PASSTHRU

include/linux/nvme.h

@@ -27,8 +27,14 @@
 #define NVME_NSID_ALL		0xffffffff
 
 enum nvme_subsys_type {
-	NVME_NQN_DISC	= 1,		/* Discovery type target subsystem */
-	NVME_NQN_NVME	= 2,		/* NVME type target subsystem */
+	/* Referral to another discovery type target subsystem */
+	NVME_NQN_DISC	= 1,
+
+	/* NVME type target subsystem */
+	NVME_NQN_NVME	= 2,
+
+	/* Current discovery type target subsystem */
+	NVME_NQN_CURR	= 3,
 };
 
 enum nvme_ctrl_type {
@@ -1312,6 +1318,12 @@ struct nvmf_common_command {
 
 #define MAX_DISC_LOGS	255
 
+/* Discovery log page entry flags (EFLAGS): */
+enum {
+	NVME_DISC_EFLAGS_EPCSD		= (1 << 1),
+	NVME_DISC_EFLAGS_DUPRETINFO	= (1 << 0),
+};
+
 /* Discovery log page entry */
 struct nvmf_disc_rsp_page_entry {
 	__u8		trtype;
@@ -1321,7 +1333,8 @@ struct nvmf_disc_rsp_page_entry {
 	__le16		portid;
 	__le16		cntlid;
 	__le16		asqsz;
-	__u8		resv8[22];
+	__le16		eflags;
+	__u8		resv10[20];
 	char		trsvcid[NVMF_TRSVCID_SIZE];
 	__u8		resv64[192];
 	char		subnqn[NVMF_NQN_FIELD_LEN];