Re: [Qemu-devel] [PATCH] spapr-vscsi: Adding VSCSI capabilities

[Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>]

Alexander Graf <agraf@suse.de> writes:

> On 26.08.2013, at 12:58, Nikunj A Dadhania wrote:
>
>> This implements capabilities exchange between host and client.
>> As at the moment no capability is supported, put zero flags everywhere
>> and return.
>> 
>> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
>> ---
>> +    rc = spapr_vio_dma_read(&s->vdev, buffer, &cap, len);
>> +    if (rc)  {
>> +        fprintf(stderr, "vscsi_send_capabilities: DMA read failure !\n");
>
> At this point cap contains random host data, no?

Yes, and we zero it out in this case.

>
>> +    }
>> +
>> +    /*
>> +     * Current implementation does not suppport any migration or
>> +     * reservation capabilities. Construct the response telling the
>> +     * guest not to use them.
>> +     */
>> +    cap.flags = 0;
>> +    cap.migration.ecl = 0;
>> +    cap.reserve.type = 0;
>> +    cap.migration.common.server_support = 0;
>> +    cap.reserve.common.server_support = 0;
>> +
>> +    rc = spapr_vio_dma_write(&s->vdev, buffer, &cap, len);
>> +    if (rc)  {
>> +        fprintf(stderr, "vscsi_send_capabilities: DMA write failure !\n");
>> +    }
>> +error_out:
>
> This is just "out" rather than "error_out", no? We also get here when we don't hit an error.

Yes, the label is more readable at the goto, where we set the error
return code. In case of no error return code is H_SUCCESS. So that we
send a response back to the guest.

Regards
Nikunj