[dpdk-dev] [PATCH] bus/pci: fix unexpected resource mapping override

[Qi Zhang <qi.z.zhang@intel.com>]

When scanning an already plugged device, the virtual address
of mapped PCI resource in rte_pci_device will be overridden
with 0, that may cause driver does not work correctly.
The fix is not to update any rte_pci_device's field if the being
scanned device's driver is already probed.

Bugzilla ID: 85
Fixes: c752998b5e2e ("pci: introduce library and driver")
Cc: stable@dpdk.org

Reported-by: Lv Geoffrey <geoffrey.lv@gmail.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
---
 drivers/bus/pci/linux/pci.c | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
index 04648ac93..b94eb7401 100644
--- a/drivers/bus/pci/linux/pci.c
+++ b/drivers/bus/pci/linux/pci.c
@@ -348,11 +348,35 @@ pci_scan_one(const char *dirname, const struct rte_pci_addr *addr)
 			if (ret < 0) {
 				rte_pci_insert_device(dev2, dev);
 			} else { /* already registered */
-				dev2->kdrv = dev->kdrv;
-				dev2->max_vfs = dev->max_vfs;
-				pci_name_set(dev2);
-				memmove(dev2->mem_resource, dev->mem_resource,
-					sizeof(dev->mem_resource));
+				if (dev2->driver == NULL) {
+					dev2->kdrv = dev->kdrv;
+					dev2->max_vfs = dev->max_vfs;
+					pci_name_set(dev2);
+					memmove(dev2->mem_resource,
+						dev->mem_resource,
+						sizeof(dev->mem_resource));
+				} else {
+					/**
+					 * If device is plugged and driver is
+					 * probed already, we don't need to do
+					 * anything here. (This happens when we
+					 * call rte_eal_hotplug_add)
+					 */
+					if (dev2->kdrv != dev->kdrv ||
+						dev2->max_vfs != dev->max_vfs)
+						/*
+						 * This should not happens.
+						 * But it is still possible if
+						 * we unbind a device from
+						 * vfio or uio before hotplug
+						 * remove and rebind it with
+						 * a different configure.
+						 * So we just print out the
+						 * error as an alarm.
+						 */
+						RTE_LOG(ERR, EAL, "Unexpected device scan at %s!\n",
+							filename);
+				}
 				free(dev);
 			}
 			return 0;
-- 
2.13.6