nvme: Add PCI transport type

Define the transport type NVMF_TRTYPE_PCI for PCI endpoint targets.
This transport type is defined using the value 0 which is reserved in
the NVMe base specifications v2.1 (Figure 294). Given that struct
nvmet_port are zeroed out on creation, to avoid having this transsport
type becoming the new default, nvmet_referral_make() and
nvmet_ports_make() are modified to initialize a port discovery address
transport type field (disc_addr.trtype) to NVMF_TRTYPE_MAX.

Any port using this transport type is also skipped and not reported in
the discovery log page (nvmet_execute_disc_get_log_page()).

The helper function nvmet_is_pci_ctrl() is also introduced to check if
a target controller uses the PCI transport.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/target/configfs.c

@@ -37,6 +37,7 @@ static struct nvmet_type_name_map nvmet_transport[] = {
 	{ NVMF_TRTYPE_RDMA,	"rdma" },
 	{ NVMF_TRTYPE_FC,	"fc" },
 	{ NVMF_TRTYPE_TCP,	"tcp" },
+	{ NVMF_TRTYPE_PCI,	"pci" },
 	{ NVMF_TRTYPE_LOOP,	"loop" },
 };
 
@@ -46,6 +47,7 @@ static const struct nvmet_type_name_map nvmet_addr_family[] = {
 	{ NVMF_ADDR_FAMILY_IP6,		"ipv6" },
 	{ NVMF_ADDR_FAMILY_IB,		"ib" },
 	{ NVMF_ADDR_FAMILY_FC,		"fc" },
+	{ NVMF_ADDR_FAMILY_PCI,		"pci" },
 	{ NVMF_ADDR_FAMILY_LOOP,	"loop" },
 };
 
@@ -1839,6 +1841,7 @@ static struct config_group *nvmet_referral_make(
 		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&port->entry);
+	port->disc_addr.trtype = NVMF_TRTYPE_MAX;
 	config_group_init_type_name(&port->group, name, &nvmet_referral_type);
 
 	return &port->group;
@@ -2064,6 +2067,7 @@ static struct config_group *nvmet_ports_make(struct config_group *group,
 	port->inline_data_size = -1;	/* < 0 == let the transport choose */
 	port->max_queue_size = -1;	/* < 0 == let the transport choose */
 
+	port->disc_addr.trtype = NVMF_TRTYPE_MAX;
 	port->disc_addr.portid = cpu_to_le16(portid);
 	port->disc_addr.adrfam = NVMF_ADDR_FAMILY_MAX;
 	port->disc_addr.treq = NVMF_TREQ_DISABLE_SQFLOW;

drivers/nvme/target/discovery.c

@@ -224,6 +224,9 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
 	}
 
 	list_for_each_entry(r, &req->port->referrals, entry) {
+		if (r->disc_addr.trtype == NVMF_TRTYPE_PCI)
+			continue;
+
 		nvmet_format_discovery_entry(hdr, r,
 				NVME_DISC_SUBSYS_NAME,
 				r->disc_addr.traddr,

drivers/nvme/target/nvmet.h

@@ -693,6 +693,11 @@ static inline bool nvmet_is_disc_subsys(struct nvmet_subsys *subsys)
     return subsys->type != NVME_NQN_NVME;
 }
 
+static inline bool nvmet_is_pci_ctrl(struct nvmet_ctrl *ctrl)
+{
+	return ctrl->port->disc_addr.trtype == NVMF_TRTYPE_PCI;
+}
+
 #ifdef CONFIG_NVME_TARGET_PASSTHRU
 void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys);
 int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys);

include/linux/nvme.h

@@ -64,6 +64,7 @@ enum {
 
 /* Transport Type codes for Discovery Log Page entry TRTYPE field */
 enum {
+	NVMF_TRTYPE_PCI		= 0,	/* PCI */
 	NVMF_TRTYPE_RDMA	= 1,	/* RDMA */
 	NVMF_TRTYPE_FC		= 2,	/* Fibre Channel */
 	NVMF_TRTYPE_TCP		= 3,	/* TCP/IP */