[dpdk-dev] [PATCH v1 1/1] bus/pci: probe PCI devices in whitelisted order

[<vattunuru@marvell.com>]

From: Vamsi Attunuru <vattunuru@marvell.com>

Current pci bus driver scans pci devices in the order that
it read from sysfs. Accordingly all or whitelisted devices
are getting probed.

Patch modifies the probing order of whitelisted pci devices
in a sequence the devices are whitelisted(using EAL flags).

It ensures the eth devices that application uses are probed
in device whitelisted sequence, in turn it facilitates the
packet forwarding applications to work without any packet
loss or performance drop when the underneath network ports
have different bandwidths. By altering the whitelist order
applications like testpmd, l2fwd can forward the ingress
traffic to egress port that has of equivalent bandwidth.

Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
---
 drivers/bus/pci/pci_common.c | 67 ++++++++++++++++++++++++++++++--------------
 1 file changed, 46 insertions(+), 21 deletions(-)

diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
index 6b46b4f..c27a0e9 100644
--- a/drivers/bus/pci/pci_common.c
+++ b/drivers/bus/pci/pci_common.c
@@ -293,32 +293,57 @@ rte_pci_probe(void)
 	struct rte_pci_device *dev = NULL;
 	size_t probed = 0, failed = 0;
 	struct rte_devargs *devargs;
-	int probe_all = 0;
+	struct rte_pci_addr addr;
 	int ret = 0;
 
-	if (rte_pci_bus.bus.conf.scan_mode != RTE_BUS_SCAN_WHITELIST)
-		probe_all = 1;
-
-	FOREACH_DEVICE_ON_PCIBUS(dev) {
-		probed++;
+	if (rte_pci_bus.bus.conf.scan_mode != RTE_BUS_SCAN_WHITELIST) {
+		/* Probe all devices */
+		FOREACH_DEVICE_ON_PCIBUS(dev) {
+			probed++;
 
-		devargs = dev->device.devargs;
-		/* probe all or only whitelisted devices */
-		if (probe_all)
 			ret = pci_probe_all_drivers(dev);
-		else if (devargs != NULL &&
-			devargs->policy == RTE_DEV_WHITELISTED)
-			ret = pci_probe_all_drivers(dev);
-		if (ret < 0) {
-			if (ret != -EEXIST) {
-				RTE_LOG(ERR, EAL, "Requested device "
-					PCI_PRI_FMT " cannot be used\n",
-					dev->addr.domain, dev->addr.bus,
-					dev->addr.devid, dev->addr.function);
-				rte_errno = errno;
-				failed++;
+			if (ret < 0) {
+				if (ret != -EEXIST) {
+					RTE_LOG(ERR, EAL, "Requested device "
+						PCI_PRI_FMT " cannot be used\n",
+						dev->addr.domain, dev->addr.bus,
+						dev->addr.devid,
+						dev->addr.function);
+					rte_errno = errno;
+					failed++;
+				}
+				ret = 0;
+			}
+		}
+	} else {
+		/* Probe only whitelisted devices */
+		RTE_EAL_DEVARGS_FOREACH("pci", devargs) {
+			if (devargs->policy != RTE_DEV_WHITELISTED)
+				continue;
+
+			devargs->bus->parse(devargs->name, &addr);
+
+			FOREACH_DEVICE_ON_PCIBUS(dev) {
+				if (rte_pci_addr_cmp(&dev->addr, &addr))
+					continue;
+				probed++;
+				ret = pci_probe_all_drivers(dev);
+				if (ret < 0) {
+					if (ret != -EEXIST) {
+						RTE_LOG(ERR, EAL,
+							"Requested device "
+							 PCI_PRI_FMT
+							"cannot be used\n",
+							dev->addr.domain,
+							dev->addr.bus,
+							dev->addr.devid,
+							dev->addr.function);
+						rte_errno = errno;
+						failed++;
+					}
+					ret = 0;
+				}
 			}
-			ret = 0;
 		}
 	}
 
-- 
2.8.4