[PATCH 3/6] vhost: fix VDUSE reconnect device start failure

[Maxime Coquelin]

On 10/23/24 18:06, David Marchand wrote:
> On Wed, Oct 23, 2024 at 5:16 PM Maxime Coquelin
> <maxime.coquelin at redhat.com> wrote:
>>
>> This patch fixes a FD leak in the VDUSE device reconnect
>> code fails to start the device.
>>
>> Also take the opportunity to refactor the related code into
>> a dedicated function.
>>
>> Fixes: da79cc7fda76 ("vhost: add reconnection support to VDUSE")
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>> ---
>>   lib/vhost/vduse.c | 63 +++++++++++++++++++++++++++++++----------------
>>   1 file changed, 42 insertions(+), 21 deletions(-)
>>
>> diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
>> index d1373d0549..c8c4761293 100644
>> --- a/lib/vhost/vduse.c
>> +++ b/lib/vhost/vduse.c
>> @@ -476,6 +476,46 @@ vduse_reconnect_handler(int fd, void *arg, int *remove)
>>          *remove = 1;
>>   }
>>
>> +static int
>> +vduse_reconnect_start_device(struct virtio_net *dev)
>> +{
>> +       int fd, ret;
>> +
>> +       /*
>> +        * Make vduse_device_start() being executed in the same
>> +        * context for both reconnection and fresh startup.
>> +        */
>> +       fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
>> +       if (fd < 0) {
>> +               VHOST_CONFIG_LOG(dev->ifname, ERR, "Failed to create reconnect efd: %s",
>> +                               strerror(errno));
>> +               ret = -1;
>> +               goto out_err;
>> +       }
>> +
>> +       ret = fdset_add(vduse.fdset, fd, vduse_reconnect_handler, NULL, dev);
>> +       if (ret) {
>> +               VHOST_CONFIG_LOG(dev->ifname, ERR, "Failed to add reconnect efd %d to vduse fdset",
>> +                               fd);
>> +               goto out_err_close;
>> +       }
>> +
>> +       ret = eventfd_write(fd, (eventfd_t)1);
>> +       if (ret < 0) {
>> +               VHOST_CONFIG_LOG(dev->ifname, ERR, "Failed to write to reconnect eventfd");
>> +               goto out_err_fdset;
>> +       }
>> +
>> +       return 0;
>> +
>> +out_err_fdset:
>> +       fdset_del(vduse.fdset, fd);
>> +out_err_close:
>> +       close(fd);
>> +out_err:
>> +       return ret;
>> +}
>> +
>>   int
>>   vduse_device_create(const char *path, bool compliant_ol_flags)
>>   {
>> @@ -741,28 +781,9 @@ vduse_device_create(const char *path, bool compliant_ol_flags)
>>          }
>>
>>          if (reconnect && dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK)  {
>> -               /*
>> -                * Make vduse_device_start() being executed in the same
>> -                * context for both reconnection and fresh startup.
>> -                */
>> -               reco_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
>> -               if (reco_fd < 0) {
>> -                       VHOST_CONFIG_LOG(name, ERR, "Failed to create reco_fd: %s",
>> -                                       strerror(errno));
>> -                       ret = -1;
>> -                       goto out_dev_destroy;
>> -               }
>> -
>> -               ret = fdset_add(vduse.fdset, reco_fd, vduse_reconnect_handler, NULL, dev);
>> +               ret = vduse_reconnect_start_device(dev);
>>                  if (ret) {
>> -                       VHOST_CONFIG_LOG(name, ERR, "Failed to add reconnect fd %d to vduse fdset",
>> -                                       reco_fd);
>> -                       goto out_dev_destroy;
>> -               }
>> -
>> -               ret = eventfd_write(reco_fd, (eventfd_t)1);
>> -               if (ret < 0) {
>> -                       VHOST_CONFIG_LOG(name, ERR, "Failed to write to reconnect eventfd");
>> +                       VHOST_CONFIG_LOG(name, ERR, "Failed to start device at reconnection");
> 
> We don't need a new log, there is already one for each error case in
> vduse_reconnect_start_device().
> 
> 

Removed in v2.

Thanks,
Maxime