external_code/nvme: direct NVMe device connect

Added interface, nvme_connect(), for connecting an NVMe device specified
by a BDF address.  Similarly to spdk_nvme_connect(), it returns a
pointer to an NVMe controller representing requested device.

Under the hood, it uses spdk_nvme_pci_device_attach() to attach the
PCI device.

Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: I15c7cabae07539cb97aba810385d26f223abfd6d
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/6665
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

test/external_code/nvme/nvme.c

@@ -55,6 +55,22 @@ static struct spdk_pci_id nvme_pci_driver_id[] = {
 SPDK_PCI_DRIVER_REGISTER(nvme_external, nvme_pci_driver_id, SPDK_PCI_DRIVER_NEED_MAPPING);
 static TAILQ_HEAD(, nvme_ctrlr) g_nvme_ctrlrs = TAILQ_HEAD_INITIALIZER(g_nvme_ctrlrs);
 
+static struct nvme_ctrlr *
+find_ctrlr_by_addr(struct spdk_pci_addr *addr)
+{
+	struct spdk_pci_addr ctrlr_addr;
+	struct nvme_ctrlr *ctrlr;
+
+	TAILQ_FOREACH(ctrlr, &g_nvme_ctrlrs, tailq) {
+		ctrlr_addr = spdk_pci_device_get_addr(ctrlr->pci_device);
+		if (spdk_pci_addr_compare(addr, &ctrlr_addr) == 0) {
+			return ctrlr;
+		}
+	}
+
+	return NULL;
+}
+
 static int
 pcie_enum_cb(void *ctx, struct spdk_pci_device *pci_dev)
 {
@@ -90,15 +106,21 @@ free_ctrlr(struct nvme_ctrlr *ctrlr)
 	free(ctrlr);
 }
 
-int
+static int
-nvme_probe(nvme_attach_cb attach_cb, void *cb_ctx)
+probe_internal(struct spdk_pci_addr *addr, nvme_attach_cb attach_cb, void *cb_ctx)
 {
 	struct nvme_ctrlr *ctrlr, *tmp;
 	TAILQ_HEAD(, nvme_ctrlr) ctrlrs = TAILQ_HEAD_INITIALIZER(ctrlrs);
 	int rc;
 
+	if (addr == NULL) {
 		rc = spdk_pci_enumerate(spdk_pci_get_driver("nvme_external"),
 					pcie_enum_cb, &ctrlrs);
+	} else {
+		rc = spdk_pci_device_attach(spdk_pci_get_driver("nvme_external"),
+					    pcie_enum_cb, &ctrlrs, addr);
+	}
+
 	if (rc != 0) {
 		SPDK_ERRLOG("Failed to enumerate PCI devices\n");
 		while (!TAILQ_EMPTY(&ctrlrs)) {
@@ -114,12 +136,33 @@ nvme_probe(nvme_attach_cb attach_cb, void *cb_ctx)
 		TAILQ_REMOVE(&ctrlrs, ctrlr, tailq);
 		TAILQ_INSERT_TAIL(&g_nvme_ctrlrs, ctrlr, tailq);
 
+		if (attach_cb != NULL) {
 			attach_cb(cb_ctx, &ctrlr->pci_device->addr, ctrlr);
 		}
+	}
 
 	return 0;
 }
 
+int
+nvme_probe(nvme_attach_cb attach_cb, void *cb_ctx)
+{
+	return probe_internal(NULL, attach_cb, cb_ctx);
+}
+
+struct nvme_ctrlr *
+nvme_connect(struct spdk_pci_addr *addr)
+{
+	int rc;
+
+	rc = probe_internal(addr, NULL, NULL);
+	if (rc != 0) {
+		return NULL;
+	}
+
+	return find_ctrlr_by_addr(addr);
+}
+
 void
 nvme_detach(struct nvme_ctrlr *ctrlr)
 {

test/external_code/nvme/nvme.h

@@ -63,6 +63,18 @@ typedef void (*nvme_attach_cb)(void *cb_ctx, const struct spdk_pci_addr *addr,
  */
 int nvme_probe(nvme_attach_cb attach_cb, void *ctx);
 
+/**
+ * Connect the NVMe driver to the device located at the given transport ID.
+ *
+ * This function is not thread safe and should only be called from one thread at
+ * a time while no other threads are actively using this NVMe device.
+ *
+ * \param addr The PCI address of the NVMe controller to connect.
+ *
+ * \return pointer to the connected NVMe controller or NULL if there is any failure.
+ */
+struct nvme_ctrlr *nvme_connect(struct spdk_pci_addr *addr);
+
 /**
  * Detach specified device returned by nvme_probe()'s attach_cb. After returning
  * the nvme_ctrlr handle is no longer valid.