Re: [Qemu-devel] [PATCH 2/5] igd-passthrough-i440FX: convert to realize()

[Eduardo Habkost <ehabkost@redhat.com>]

On Fri, Dec 18, 2015 at 07:03:49PM +0800, Cao jin wrote:
> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
> ---
>  hw/pci-host/piix.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
> index 715208b..e3840f0 100644
> --- a/hw/pci-host/piix.c
> +++ b/hw/pci-host/piix.c
> @@ -761,7 +761,7 @@ static const IGDHostInfo igd_host_bridge_infos[] = {
>      {0xa8, 4},  /* SNB: base of GTT stolen memory */
>  };
>  
> -static int host_pci_config_read(int pos, int len, uint32_t val)
> +static int host_pci_config_read(int pos, int len, uint32_t val, Error **errp)

You don't need the return value anymore, if you report errors
through the errp parameter. The function can be void, now.

>  {
>      char path[PATH_MAX];
>      int config_fd;
> @@ -772,15 +772,18 @@ static int host_pci_config_read(int pos, int len, uint32_t val)
>      int ret = 0;
>  
>      if (rc >= size || rc < 0) {
> +        error_setg(errp, "No such device");
>          return -ENODEV;
>      }
>  
>      config_fd = open(path, O_RDWR);
>      if (config_fd < 0) {
> +        error_setg(errp, "No such device");
>          return -ENODEV;
>      }
>  
>      if (lseek(config_fd, pos, SEEK_SET) != pos) {
> +        error_setg(errp, "lseek err: %s", strerror(errno));

What about error_setg_errno()?

>          ret = -errno;
>          goto out;
>      }
> @@ -789,13 +792,14 @@ static int host_pci_config_read(int pos, int len, uint32_t val)
>      } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
>      if (rc != len) {
>          ret = -errno;
> +        error_setg(errp, "read err: %s", strerror(errno));

Same here.

>      }
>  out:
>      close(config_fd);
>      return ret;
>  }
>  
> -static int igd_pt_i440fx_initfn(struct PCIDevice *pci_dev)
> +static void igd_pt_i440fx_realize(struct PCIDevice *pci_dev, Error **errp)
>  {
>      uint32_t val = 0;
>      int rc, i, num;
> @@ -805,14 +809,12 @@ static int igd_pt_i440fx_initfn(struct PCIDevice *pci_dev)
>      for (i = 0; i < num; i++) {
>          pos = igd_host_bridge_infos[i].offset;
>          len = igd_host_bridge_infos[i].len;
> -        rc = host_pci_config_read(pos, len, val);
> +        rc = host_pci_config_read(pos, len, val, errp);
>          if (rc) {

The usual pattern for error checking and propagation is:

    Error *err;
    host_pci_config_read(pos, len, val, &err);
    if (err) {
        error_propagate(errp, local_err);
        return;
    }

> -            return -ENODEV;
> +            return;
>          }
>          pci_default_write_config(pci_dev, pos, val, len);
>      }
> -
> -    return 0;
>  }
>  
>  static void igd_passthrough_i440fx_class_init(ObjectClass *klass, void *data)
> @@ -820,7 +822,7 @@ static void igd_passthrough_i440fx_class_init(ObjectClass *klass, void *data)
>      DeviceClass *dc = DEVICE_CLASS(klass);
>      PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
>  
> -    k->init = igd_pt_i440fx_initfn;
> +    k->realize = igd_pt_i440fx_realize;
>      dc->desc = "IGD Passthrough Host bridge";
>  }
>  
> -- 
> 2.1.0
> 
> 
> 

-- 
Eduardo