[PATCH v4 3/5] bus/vdev: bus scan by multi-process channel

[Jianfeng Tan <jianfeng.tan@intel.com>]

To scan the vdevs in primary, we send request to primary process
to obtain the names for vdevs.

Only the name is shared from the primary. In probe(), the device
driver is supposed to locate (or request more) the detail
information from the primary.

Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
Reviewed-by: Qi Zhang <qi.z.zhang@intel.com>
---
 drivers/bus/vdev/Makefile |   1 +
 drivers/bus/vdev/vdev.c   | 100 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+)

diff --git a/drivers/bus/vdev/Makefile b/drivers/bus/vdev/Makefile
index 24d424a..bd0bb89 100644
--- a/drivers/bus/vdev/Makefile
+++ b/drivers/bus/vdev/Makefile
@@ -10,6 +10,7 @@ LIB = librte_bus_vdev.a
 
 CFLAGS += -O3
 CFLAGS += $(WERROR_FLAGS)
+CFLAGS += -DALLOW_EXPERIMENTAL_API
 
 # versioning export map
 EXPORT_MAP := rte_bus_vdev_version.map
diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
index 70964f5..ce5332a 100644
--- a/drivers/bus/vdev/vdev.c
+++ b/drivers/bus/vdev/vdev.c
@@ -18,6 +18,7 @@
 #include <rte_memory.h>
 #include <rte_tailq.h>
 #include <rte_spinlock.h>
+#include <rte_string_fns.h>
 #include <rte_errno.h>
 
 #include "rte_bus_vdev.h"
@@ -316,6 +317,77 @@ rte_vdev_uninit(const char *name)
 	return ret;
 }
 
+struct vdev_param {
+#define VDEV_SCAN_REQ	1
+#define VDEV_SCAN_ONE	2
+#define VDEV_SCAN_REP	3
+	int type;
+	int num;
+	char name[RTE_DEV_NAME_MAX_LEN];
+};
+
+static int vdev_plug(struct rte_device *dev);
+
+/**
+ * This function works as the action for both primary and secondary process
+ * for static vdev discovery when a secondary process is booting.
+ *
+ * step 1, secondary process sends a sync request to ask for vdev in primary;
+ * step 2, primary process receives the request, and send vdevs one by one;
+ * step 3, primary process sends back reply, which indicates how many vdevs
+ * are sent.
+ */
+static int
+vdev_action(const struct rte_mp_msg *mp_msg, const void *peer)
+{
+	struct rte_vdev_device *dev;
+	struct rte_mp_msg mp_resp;
+	struct vdev_param *ou = (struct vdev_param *)&mp_resp.param;
+	const struct vdev_param *in = (const struct vdev_param *)mp_msg->param;
+	const char *devname;
+	int num;
+
+	strcpy(mp_resp.name, "vdev");
+	mp_resp.len_param = sizeof(*ou);
+	mp_resp.num_fds = 0;
+
+	switch (in->type) {
+	case VDEV_SCAN_REQ:
+		ou->type = VDEV_SCAN_ONE;
+		ou->num = 1;
+		num = 0;
+
+		rte_spinlock_lock(&vdev_device_list_lock);
+		TAILQ_FOREACH(dev, &vdev_device_list, next) {
+			devname = rte_vdev_device_name(dev);
+			if (strlen(devname) == 0)
+				VDEV_LOG(INFO, "vdev with no name is not sent");
+			VDEV_LOG(INFO, "send vdev, %s", devname);
+			strlcpy(ou->name, devname, RTE_DEV_NAME_MAX_LEN);
+			if (rte_mp_sendmsg(&mp_resp) < 0)
+				VDEV_LOG(ERR, "send vdev, %s, failed, %s",
+					 devname, strerror(rte_errno));
+			num++;
+		}
+		rte_spinlock_unlock(&vdev_device_list_lock);
+
+		ou->type = VDEV_SCAN_REP;
+		ou->num = num;
+		if (rte_mp_reply(&mp_resp, peer) < 0)
+			VDEV_LOG(ERR, "Failed to reply a scan request");
+		break;
+	case VDEV_SCAN_ONE:
+		VDEV_LOG(INFO, "receive vdev, %s", in->name);
+		if (insert_vdev(in->name, NULL, NULL) < 0)
+			VDEV_LOG(ERR, "failed to add vdev, %s", in->name);
+		break;
+	default:
+		VDEV_LOG(ERR, "vdev cannot recognize this message");
+	}
+
+	return 0;
+}
+
 static int
 vdev_scan(void)
 {
@@ -323,6 +395,34 @@ vdev_scan(void)
 	struct rte_devargs *devargs;
 	struct vdev_custom_scan *custom_scan;
 
+	if (rte_mp_action_register("vdev", vdev_action) < 0 &&
+	    rte_errno != EEXIST) {
+		VDEV_LOG(ERR, "vdev fails to add action");
+		return -1;
+	}
+
+	if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
+		struct rte_mp_msg mp_req, *mp_rep;
+		struct rte_mp_reply mp_reply;
+		struct timespec ts = {.tv_sec = 5, .tv_nsec = 0};
+		struct vdev_param *req = (struct vdev_param *)mp_req.param;
+		struct vdev_param *resp;
+
+		strcpy(mp_req.name, "vdev");
+		mp_req.len_param = sizeof(*req);
+		mp_req.num_fds = 0;
+		req->type = VDEV_SCAN_REQ;
+		if (rte_mp_request_sync(&mp_req, &mp_reply, &ts) == 0 &&
+		    mp_reply.nb_received == 1) {
+			mp_rep = &mp_reply.msgs[0];
+			resp = (struct vdev_param *)mp_rep->param;
+			VDEV_LOG(INFO, "Received %d vdevs", resp->num);
+		} else
+			VDEV_LOG(ERR, "Failed to request vdev from primary");
+
+		/* Fall through to allow private vdevs in secondary process */
+	}
+
 	/* call custom scan callbacks if any */
 	rte_spinlock_lock(&vdev_custom_scan_lock);
 	TAILQ_FOREACH(custom_scan, &vdev_custom_scans, next) {
-- 
2.7.4