Re: [Qemu-devel] [RFC PATCH v5 6/6] virtio-blk : Refactor virtio-blk.

["KONRAD Frédéric" <fred.konrad@greensocs.com>]

On 05/12/2012 17:25, Peter Maydell wrote:
> On 4 December 2012 14:35,  <fred.konrad@greensocs.com> wrote:
>> From: KONRAD Frederic <fred.konrad@greensocs.com>
>>
>> Create virtio-blk which extends virtio-device, so it can be connected on
>> virtio-bus.
>>
>> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
>> ---
>>   hw/virtio-blk.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++++--------
>>   hw/virtio-blk.h |   4 ++
>>   2 files changed, 150 insertions(+), 24 deletions(-)
>>
>> diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
>> index e25cc96..ee1ea8b 100644
>> --- a/hw/virtio-blk.c
>> +++ b/hw/virtio-blk.c
>> @@ -21,24 +21,42 @@
>>   #ifdef __linux__
>>   # include <scsi/sg.h>
>>   #endif
>> +#include "virtio-bus.h"
>>
>> +/* Take this structure as our device structure. */
>>   typedef struct VirtIOBlock
>>   {
>> +    /*
>> +     * Adding parent_obj breaks to_virtio_blk cast function,
>> +     * and virtio_blk_init.
>> +     */
>> +    DeviceState parent_obj;
>> +    /*
>> +     * We don't need that anymore, as we'll use QOM cast to get the
>> +     * VirtIODevice. Just temporary keep it, for not breaking functionality.
>> +     */
>>       VirtIODevice vdev;
> This doesn't make sense. After your previous patch, VirtIODevice
> is-a DeviceState, and VirtIOBlock already is-a VirtIODevice,
> so there's nothing to do here. Adding this parent_obj field
> here is just breaking things (it would make the VirtIOBlock
> into a direct child of DeviceState, which isn't what we want).
>
Ok, I think you're right, I'll check.

>>       BlockDriverState *bs;
>>       VirtQueue *vq;
>>       void *rq;
>>       QEMUBH *bh;
>>       BlockConf *conf;
>> -    VirtIOBlkConf *blk;
>> +    /*
>> +     * We can't use pointer with properties.
>> +     */
>> +    VirtIOBlkConf blk;
>>       unsigned short sector_mask;
>>       DeviceState *qdev;
>>   } VirtIOBlock;
>>
>> -static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
>> -{
>> -    return (VirtIOBlock *)vdev;
>> -}
>> +/*
>> + * Use the QOM cast, so we don't need that anymore.
>> + *
>> + * static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
>> + * {
>> + *     return (VirtIOBlock *)vdev;
>> + * }
>> + */
> If we don't need it, just delete it.
>
> -- PMM
Yes, sure, I put it in comment to explain, why I deleted it.

Thanks,

Fred.