Re: [Qemu-devel] Re: [PATCH] scsi-generic: bugfixes for 'SCSIRequest' conversion

[Kevin Wolf]

Am 23.12.2010 22:58, schrieb Nicholas A. Bellinger:
> On Tue, 2010-12-21 at 12:49 +1100, Benjamin Herrenschmidt wrote:
>>> Yep, so it appears that commit 89c0f6438d16 did introduce the bogus
>>> 'double complete' in scsi_read_complete, which I think was intended to
>>> handle residual counts for TYPE_TYPE...
>>>
>>>  /* Cancel a pending data transfer.  */
>>> @@ -251,6 +257,8 @@ static void scsi_read_complete(void * opaque, int ret)
>>>
>>>      r->len = -1;
>>>      s->completion(s->opaque, SCSI_REASON_DATA, r->tag, len);
>>> +    if (len == 0)
>>> +        scsi_command_complete(r, 0);
>>>  }
>>>
>>> I am currently under the assumption for this and bsg_read_complete that
>>> s->completion(..., len) is handling the residual count back to block.
>>>
>>> Is this correct..?
>>
>> So I just debugged a crash where loading my vscsi driver kills qemu
>> (segfault) after trying to complete a command twice with scsi-generic.
>>
>> Removing the above hunk fixes it. So this is a genuine fix that should
>> be applied (asap even :-)
>>
> 
> Hi Ben,
> 
> Thanks for verifying this one.  Kevin, please make sure this original
> patch to drop the bogus double complete gets picked up.

Wasn't the original patch NACKed by Hannes in parts? Can you re-post a
patch that includes only this specific fix?

Kevin