Re: [Qemu-devel] [PATCH] qed: adjust the way to get nb_sectors

[Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>]

On Mon, Oct 31, 2011 at 02:11:00PM +0000, Stefan Hajnoczi wrote:
>From: Stefan Hajnoczi <stefanha@gmail.com>
>To: Zhi Yong Wu <zwu.kernel@gmail.com>
>Cc: Kevin Wolf <kwolf@redhat.com>, Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>,
> qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com
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>On Mon, Oct 31, 2011 at 8:25 AM, Zhi Yong Wu <zwu.kernel@gmail.com> wrote:
>> On Mon, Oct 31, 2011 at 4:10 PM, Kevin Wolf <kwolf@redhat.com> wrote:
>>> Am 31.10.2011 04:01, schrieb Zhi Yong Wu:
>>>> It is better to use qiov.size in qed-table.c to get nb_sectors than iov.iov_len.
>>>>
>>>> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>>>
>>> The commit message should probably say why it's better. Not saying
>>> otherwise, but I can't see the different at the first sight.
>> They are equal, but if the number of iov isn't ONE, they will be not
>> equal. qiov.size contains the sum of all iov's size while iov.iov_len
>> is only the size of one iov. Although in current scenario, they are
>> equal, but i think that it is better if qiov.size is used.
>
>I see your reasoning.  Especially in qed_read_table_cb() it's nice to
>use qiov->size because that function doesn't obviously use a single
>struct iovec.
>
>If you want to change it I agree but please send a patch with a proper
>explanation that mentions that this is purely a refactoring (does not
>change behavior) and why.
OK.
>
>Stefan
>