Re: [PATCH 6/7] nvme: Add connect option 'discovery'

Add a connect option 'discovery' to specify that the connection
should be made to a discovery controller, not a normal I/O controller.
With discovery controllers supporting unique subsystem NQNs we
cannot easily distinguish by the subsystem NQN if this should be
a discovery connection, but we need this information to blank out
options not supported by discovery controllers.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
---
  drivers/nvme/host/core.c    | 7 +++++++
  drivers/nvme/host/fabrics.c | 6 +++++-
  drivers/nvme/host/fabrics.h | 1 +
  3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 1ed1b7be2812..ad01e2778cb6 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c

@@ -2715,6 +2715,13 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
  	else
  		subsys->subtype = NVME_NQN_NVME;
  
+	if (nvme_discovery_ctrl(ctrl) && subsys->subtype != NVME_NQN_DISC) {
+		dev_err(ctrl->device,
+			"Subsystem %s is not a discovery controller",
+			subsys->subnqn);
+		kfree(subsys);
+		return -EINVAL;
+	}
  	subsys->awupf = le16_to_cpu(id->awupf);
  #ifdef CONFIG_NVME_MULTIPATH
  	subsys->iopolicy = NVME_IOPOLICY_NUMA;

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 668c6bb7a567..c5a2b71c5268 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c

@@ -548,6 +548,7 @@ static const match_table_t opt_tokens = {
  	{ NVMF_OPT_NR_POLL_QUEUES,	"nr_poll_queues=%d"	},
  	{ NVMF_OPT_TOS,			"tos=%d"		},
  	{ NVMF_OPT_FAIL_FAST_TMO,	"fast_io_fail_tmo=%d"	},
+	{ NVMF_OPT_DISCOVERY,		"discovery"		},
  	{ NVMF_OPT_ERR,			NULL			}
  };
  

@@ -823,6 +824,9 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
  			}
  			opts->tos = token;
  			break;
+		case NVMF_OPT_DISCOVERY:
+			opts->discovery_nqn = true;
+			break;
  		default:
  			pr_warn("unknown parameter or missing value '%s' in ctrl creation request\n",
  				p);

@@ -949,7 +953,7 @@ EXPORT_SYMBOL_GPL(nvmf_free_options);
  #define NVMF_ALLOWED_OPTS	(NVMF_OPT_QUEUE_SIZE | NVMF_OPT_NR_IO_QUEUES | \
  				 NVMF_OPT_KATO | NVMF_OPT_HOSTNQN | \
  				 NVMF_OPT_HOST_ID | NVMF_OPT_DUP_CONNECT |\
-				 NVMF_OPT_DISABLE_SQFLOW |\
+				 NVMF_OPT_DISABLE_SQFLOW | NVMF_OPT_DISCOVERY |\
  				 NVMF_OPT_FAIL_FAST_TMO)
  
  static struct nvme_ctrl *

diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index a146cb903869..b61b666e10ec 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/drivers/nvme/host/fabrics.h

@@ -67,6 +67,7 @@ enum {
  	NVMF_OPT_TOS		= 1 << 19,
  	NVMF_OPT_FAIL_FAST_TMO	= 1 << 20,
  	NVMF_OPT_HOST_IFACE	= 1 << 21,
+	NVMF_OPT_DISCOVERY	= 1 << 22,
  };
  
  /**