RE: [PATCH net-next 1/3] net/usb/r8152: support aggregation

From: hayeswang
Date: Tue Aug 13 2013 - 23:03:31 EST


David Miller [mailto:davem@xxxxxxxxxxxxx]
> Sent: Wednesday, August 14, 2013 7:41 AM
> To: oneukum@xxxxxxx
> Cc: Hayeswang; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH net-next 1/3] net/usb/r8152: support aggregation
>
[...]
> > I don't understand what problem the function is supposed to
> fix. As long
> > as I don't understand it I cannot say for sure whether it
> is correct.
> > There seems no obvious reason for a memory barrier, but
> there may be a
> > hidden reason I don't see.
>
> Hayes, when Oliver asks you "Against what is the memory
> barrier?" he is asking
> you which memory operations you are trying to order.
>
> You do not explain this in your commit message, nor do you
> explain it with a
> suitable comment. This is not acceptable.
>
> It is absolutely critical, that any time you add a memory
> barrier, you add a
> comment above the new memory barrier explaining exactly what
> the barrier is
> trying to achieve.
>
> In fact, this is required by our coding standards.

I just want to make sure the rx_desc and rx_data are set correctly before
they are used. However, I study some examples and information from internet,
and I think that the memory barries is not necessary here. Therefore, I would
remove them later.

Best Regards,
Hayes

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