nvme: add hostid token to fabric options

Currently we have no way to define a stable host-id but always use the one
which is randomly generated when we add the host or use the default host.

Provide a "hostid=%s" for user-space to pass in a persistent host-id which
overrides the randomly generated one.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/fabrics.c

@@ -58,7 +58,6 @@ static struct nvmf_host *nvmf_host_add(const char *hostnqn)
 
 	kref_init(&host->ref);
 	memcpy(host->nqn, hostnqn, NVMF_NQN_SIZE);
-	uuid_gen(&host->id);
 
 	list_add_tail(&host->list, &nvmf_hosts);
 out_unlock:
@@ -75,7 +74,6 @@ static struct nvmf_host *nvmf_host_default(void)
 		return NULL;
 
 	kref_init(&host->ref);
-	uuid_gen(&host->id);
 	snprintf(host->nqn, NVMF_NQN_SIZE,
 		"nqn.2014-08.org.nvmexpress:NVMf:uuid:%pUb", &host->id);
 
@@ -565,6 +563,7 @@ static const match_table_t opt_tokens = {
 	{ NVMF_OPT_KATO,		"keep_alive_tmo=%d"	},
 	{ NVMF_OPT_HOSTNQN,		"hostnqn=%s"		},
 	{ NVMF_OPT_HOST_TRADDR,		"host_traddr=%s"	},
+	{ NVMF_OPT_HOST_ID,		"hostid=%s"		},
 	{ NVMF_OPT_ERR,			NULL			}
 };
 
@@ -576,6 +575,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 	int token, ret = 0;
 	size_t nqnlen  = 0;
 	int ctrl_loss_tmo = NVMF_DEF_CTRL_LOSS_TMO;
+	uuid_t hostid;
 
 	/* Set defaults */
 	opts->queue_size = NVMF_DEF_QUEUE_SIZE;
@@ -586,6 +586,8 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 	if (!options)
 		return -ENOMEM;
 
+	uuid_gen(&hostid);
+
 	while ((p = strsep(&o, ",\n")) != NULL) {
 		if (!*p)
 			continue;
@@ -742,6 +744,17 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			}
 			opts->host_traddr = p;
 			break;
+		case NVMF_OPT_HOST_ID:
+			p = match_strdup(args);
+			if (!p) {
+				ret = -ENOMEM;
+				goto out;
+			}
+			if (uuid_parse(p, &hostid)) {
+				ret = -EINVAL;
+				goto out;
+			}
+			break;
 		default:
 			pr_warn("unknown parameter or missing value '%s' in ctrl creation request\n",
 				p);
@@ -761,6 +774,8 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 		opts->host = nvmf_default_host;
 	}
 
+	uuid_copy(&opts->host->id, &hostid);
+
 out:
 	if (!opts->discovery_nqn && !opts->kato)
 		opts->kato = NVME_DEFAULT_KATO;
@@ -821,7 +836,8 @@ EXPORT_SYMBOL_GPL(nvmf_free_options);
 
 #define NVMF_REQUIRED_OPTS	(NVMF_OPT_TRANSPORT | NVMF_OPT_NQN)
 #define NVMF_ALLOWED_OPTS	(NVMF_OPT_QUEUE_SIZE | NVMF_OPT_NR_IO_QUEUES | \
-				 NVMF_OPT_KATO | NVMF_OPT_HOSTNQN)
+				 NVMF_OPT_KATO | NVMF_OPT_HOSTNQN | \
+				 NVMF_OPT_HOST_ID)
 
 static struct nvme_ctrl *
 nvmf_create_ctrl(struct device *dev, const char *buf, size_t count)

drivers/nvme/host/fabrics.h

@@ -56,6 +56,7 @@ enum {
 	NVMF_OPT_RECONNECT_DELAY = 1 << 9,
 	NVMF_OPT_HOST_TRADDR	= 1 << 10,
 	NVMF_OPT_CTRL_LOSS_TMO	= 1 << 11,
+	NVMF_OPT_HOST_ID	= 1 << 12,
 };
 
 /**