From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wen Congyang <wency@cn.fujitsu.com>
Subject: Re: [PATCH 16/27] tools/libxl: Infrastructure for
 reading a libxl migration v2 stream
Date: Wed, 17 Jun 2015 18:01:51 +0800
Message-ID: <5581458F.5030108@cn.fujitsu.com>
References: <1434375880-30914-1-git-send-email-andrew.cooper3@citrix.com>
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To: Andrew Cooper <andrew.cooper3@citrix.com>, Xen-devel <xen-devel@lists.xen.org>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>, Yang Hongyang <yanghy@cn.fujitsu.com>, Wei Liu <wei.liu2@citrix.com>, Ian Campbell <Ian.Campbell@citrix.com>, Ross Lagerwall <ross.lagerwall@citrix.com>
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On 06/17/2015 05:50 PM, Andrew Cooper wrote:
> On 17/06/15 08:57, Wen Congyang wrote:
>>> +    /* Queue up reading the body. */
>>>> +    size_t bytes_to_read;
>>>> +
>>>> +    switch (rec_hdr->type) {
>>>> +        /*
>>>> +         * Emulator records want to retain the blob in the pipe, for a further
>>>> +         * datacopier call to move elsewhere.  Just read the emulator header.
>>>> +         */
>> In this case, we should not call ROUNDUP().
>>
>>>> +    case REC_TYPE_EMULATOR_CONTEXT:
>>>> +        bytes_to_read = sizeof(struct libxl_sr_emulator_hdr);
>>>> +        break;
>>>> +
>>>> +    default:
>>>> +        bytes_to_read = rec_hdr->length;
>>>> +        break;
>>>> +    }
>>>> +
>>>> +    bytes_to_read = ROUNDUP(bytes_to_read, REC_ALIGN_ORDER);
>> So, I think it is better to move ROUNDUP to default case.
>>
>> Thanks
>> Wen Congyang
>>
> 
> sizeof(struct libxl_sr_emulator_hdr) is cunningly of the appropriate
> order already.

Yes

> 
> I suppose it is probably better to move the roundup into the default
> case and assert() appropriate alignment after the switch()

Do you mean the sub-header must be aligned

Thanks
Wen Congyang

> 
> ~Andrew
> .
>