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

[Stefan Hajnoczi]

On Mon, Oct 31, 2011 at 8:25 AM, Zhi Yong Wu <address@hidden> wrote:
> On Mon, Oct 31, 2011 at 4:10 PM, Kevin Wolf <address@hidden> 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 <address@hidden>
>>
>> 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.

Stefan