| Message ID | 1512571278-13196-1-git-send-email-ivan.khoronzhuk@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [net-next] net: ethernet: ti: cpdma: rate is not changed - correct case | expand |
On Wed, Dec 06, 2017 at 04:35:45PM -0500, David Miller wrote: > From: Ivan Khoronzhuk <ivan.khoronzhuk@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.khoronzhuk@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. > > So I would instead remove this check completely since it can never trigger. -- Regards, Ivan Khoronzhuk
On Thu, Dec 07, 2017 at 02:50:24PM -0500, David Miller wrote: > From: Ivan Khoronzhuk <ivan.khoronzhuk@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.khoronzhuk@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.khoronzhuk@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. -- Regards, Ivan Khoronzhuk
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; ctlr = ch->ctlr; spin_lock_irqsave(&ctlr->lock, flags);
If rate is the same as set it's correct case. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> --- Based on net-next/master drivers/net/ethernet/ti/davinci_cpdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.7.4