Re: [PATCH] vdpa/ifc: fix update_datapath error handling

[Maxime Coquelin]

Hi,

On 10/18/22 09:22, Taekyung Kim wrote:

Stop and return the error code if update_datapath fails.
update_datapath prepares resources for the vdpa device.
The driver should not perform any further actions
if update_datapath returns an error.

You need to add Fixes tag and Cc sta...@dpdk.org, so that it is
backported to relevant LTS branches.

Signed-off-by: Taekyung Kim <kim.tae.ky...@navercorp.com>
---
  drivers/vdpa/ifc/ifcvf_vdpa.c | 20 ++++++++++++++++----
  1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/vdpa/ifc/ifcvf_vdpa.c b/drivers/vdpa/ifc/ifcvf_vdpa.c
index d5ac583589..795967e998 100644
--- a/drivers/vdpa/ifc/ifcvf_vdpa.c
+++ b/drivers/vdpa/ifc/ifcvf_vdpa.c
@@ -1063,7 +1063,10 @@ ifcvf_dev_config(int vid)
        internal = list->internal;
        internal->vid = vid;
        rte_atomic32_set(&internal->dev_attached, 1);
-       update_datapath(internal);
+       if (update_datapath(internal) < 0) {
+               DRV_LOG(ERR, "failed to update datapath: %p", vdev);
+               return -1;
+       }

if (rte_vhost_host_notifier_ctrl(vid, RTE_VHOST_QUEUE_ALL, true) != 0)

                DRV_LOG(NOTICE, "vDPA (%s): software relay is used.",
@@ -1105,7 +1108,10 @@ ifcvf_dev_close(int vid)
                internal->sw_fallback_running = false;
        } else {
                rte_atomic32_set(&internal->dev_attached, 0);
-               update_datapath(internal);
+               if (update_datapath(internal) < 0) {
+                       DRV_LOG(ERR, "failed to update datapath: %p", vdev);
+                       return -1;
+               }
        }

internal->configured = 0;

@@ -1632,7 +1638,10 @@ ifcvf_pci_probe(struct rte_pci_driver *pci_drv 
__rte_unused,
        pthread_mutex_unlock(&internal_list_lock);

rte_atomic32_set(&internal->started, 1);

-       update_datapath(internal);
+       if (update_datapath(internal) < 0) {
+               DRV_LOG(ERR, "failed to update datapath: %s", pci_dev->name);
+               return -1;
+       }

This is not enough, you need to free resources allocated before,
otherwise you introduce memory leaks.

Basically, you should goto error instead o directly returning -1.

rte_kvargs_free(kvlist);

        return 0;
@@ -1661,7 +1670,10 @@ ifcvf_pci_remove(struct rte_pci_device *pci_dev)

internal = list->internal;

        rte_atomic32_set(&internal->started, 0);
-       update_datapath(internal);
+       if (update_datapath(internal) < 0) {
+               DRV_LOG(ERR, "failed to update datapath: %s", pci_dev->name);
+               return -1;
+       }

I think we should not return early here, because we still want to clean
as much as possible on remove. maybe just keep the error message.

        rte_pci_unmap_device(internal->pdev);
        rte_vfio_container_destroy(internal->vfio_container_fd);

Thanks,
Maxime