Re: [Qemu-devel] [RFC v2 05/12] vhost-user: split vhost_user_read()

[Marc-André Lureau]

Hi

On Fri, Jun 8, 2018 at 4:57 PM, Philippe Mathieu-Daudé <address@hidden> wrote:
> On 06/01/2018 01:27 PM, Marc-André Lureau wrote:
>> Split vhost_user_read(), so only header can be read with
>> vhost_user_read_header().
>>
>> Signed-off-by: Marc-André Lureau <address@hidden>
>> ---
>>  hw/virtio/vhost-user.c | 27 +++++++++++++++++++--------
>>  1 file changed, 19 insertions(+), 8 deletions(-)
>>
>> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
>> index cc9298792d..a87db01e55 100644
>> --- a/hw/virtio/vhost-user.c
>> +++ b/hw/virtio/vhost-user.c
>> @@ -196,7 +196,7 @@ static bool ioeventfd_enabled(void)
>>      return kvm_enabled() && kvm_eventfds_enabled();
>>  }
>>
>> -static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
>> +static int vhost_user_read_header(struct vhost_dev *dev, VhostUserMsg *msg)
>
> Can this be simply:
>
> static int vhost_user_read_header(CharBackend *chr, VhostUserMsg *msg) ?

It's more convenient and uniform with vhost_user_read() and friends if
it takes vhost_dev as argument. You can also see in patch "vhost-user:
add vhost_user_input_get_config()" that vhost_user_read_header() is
called fromwithout CharBackend* as variable in the caller.

>>  {
>>      struct vhost_user *u = dev->opaque;
>>      CharBackend *chr = u->chr;
>> @@ -207,7 +207,7 @@ static int vhost_user_read(struct vhost_dev *dev, 
>> VhostUserMsg *msg)
>>      if (r != size) {
>>          error_report("Failed to read msg header. Read %d instead of %d."
>>                       " Original request %d.", r, size, msg->hdr.request);
>> -        goto fail;
>> +        return -1;
>>      }
>>
>>      /* validate received flags */
>> @@ -215,7 +215,21 @@ static int vhost_user_read(struct vhost_dev *dev, 
>> VhostUserMsg *msg)
>>          error_report("Failed to read msg header."
>>                  " Flags 0x%x instead of 0x%x.", msg->hdr.flags,
>>                  VHOST_USER_REPLY_MASK | VHOST_USER_VERSION);
>> -        goto fail;
>> +        return -1;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
>> +{
>> +    struct vhost_user *u = dev->opaque;
>> +    CharBackend *chr = u->chr;
>> +    uint8_t *p = (uint8_t *) msg;
>> +    int r, size;
>> +
>> +    if (vhost_user_read_header(dev, msg) < 0) {
>> +        return -1;
>>      }
>>
>>      /* validate message size is sane */
>> @@ -223,7 +237,7 @@ static int vhost_user_read(struct vhost_dev *dev, 
>> VhostUserMsg *msg)
>>          error_report("Failed to read msg header."
>>                  " Size %d exceeds the maximum %zu.", msg->hdr.size,
>>                  VHOST_USER_PAYLOAD_SIZE);
>> -        goto fail;
>> +        return -1;
>>      }
>>
>>      if (msg->hdr.size) {
>> @@ -233,14 +247,11 @@ static int vhost_user_read(struct vhost_dev *dev, 
>> VhostUserMsg *msg)
>>          if (r != size) {
>>              error_report("Failed to read msg payload."
>>                           " Read %d instead of %d.", r, msg->hdr.size);
>> -            goto fail;
>> +            return -1;
>>          }
>>      }
>>
>>      return 0;
>> -
>> -fail:
>> -    return -1;
>>  }
>>
>>  static int process_message_reply(struct vhost_dev *dev,
>>