On Thu, Dec 07, 2017 at 03:13:15PM -0500, David Miller wrote: > From: Ivan Khoronzhuk <ivan.khoronz...@linaro.org> > Date: Thu, 7 Dec 2017 22:10:06 +0200 > > > On Thu, Dec 07, 2017 at 02:50:24PM -0500, David Miller wrote: > >> From: Ivan Khoronzhuk <ivan.khoronz...@linaro.org> > >> Date: Thu, 7 Dec 2017 21:48:56 +0200 > >> > >> > On Wed, Dec 06, 2017 at 04:35:45PM -0500, David Miller wrote: > >> >> From: Ivan Khoronzhuk <ivan.khoronz...@linaro.org> > >> >> Date: Wed, 6 Dec 2017 16:41:18 +0200 > >> >> > >> >> > If rate is the same as set it's correct case. > >> >> > > >> >> > Signed-off-by: Ivan Khoronzhuk <ivan.khoronz...@linaro.org> > >> >> > --- > >> >> > Based on net-next/master > >> >> > > >> >> > drivers/net/ethernet/ti/davinci_cpdma.c | 2 +- > >> >> > 1 file changed, 1 insertion(+), 1 deletion(-) > >> >> > > >> >> > diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c > >> >> > b/drivers/net/ethernet/ti/davinci_cpdma.c > >> >> > index e4d6edf..dbe9167 100644 > >> >> > --- a/drivers/net/ethernet/ti/davinci_cpdma.c > >> >> > +++ b/drivers/net/ethernet/ti/davinci_cpdma.c > >> >> > @@ -841,7 +841,7 @@ int cpdma_chan_set_rate(struct cpdma_chan *ch, > >> >> > u32 rate) > >> >> > return -EINVAL; > >> >> > > >> >> > if (ch->rate == rate) > >> >> > - return rate; > >> >> > + return 0; > >> >> > >> >> Looking at the one and only caller of this function, > >> >> cpsw_ndo_set_tx_maxrate, it > >> >> makes sure this can never, ever, happen. > >> > In current circumstances yes, it will never happen. > >> > But I caught it while adding related code and better return 0 if upper > >> > caller > >> > doesn't have such check. Suppose that cpdma module is responsible for > >> > itself > >> > and if it's critical I can send this patch along with whole related > >> > series. > >> > >> You have to decide one way or the other, who is responsible. > >> > >> I think checking higher up is better because it's cheaper at that point to > >> look at the per-netdev queue rate setting before moving down deeper into > >> the > >> driver specific data-structures. > > > > No objection, but upper caller not always knows current rate and for doing > > like > > this it needs read it first, and this is also some redundancy. > > How can the upper caller not know the current rate? The rate is > always stored in the generic netdev per-queue datastructure. > > And that's what existing code checks right now. Right now, when generic netdev only caller - yes.
-- Regards, Ivan Khoronzhuk
