The datatype of rx_coalesce_usecs is u32, always larger or equal to zero.
Previous checking does not include value 0, this patch removes the
checking to handle the value 0.
Signed-off-by: Gan Yi Fang <[email protected]>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 35c8dd92d369..6ed0e683b5e0 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -917,7 +917,7 @@ static int __stmmac_set_coalesce(struct net_device *dev,
else if (queue >= max_cnt)
return -EINVAL;
- if (priv->use_riwt && (ec->rx_coalesce_usecs > 0)) {
+ if (priv->use_riwt) {
rx_riwt = stmmac_usec2riwt(ec->rx_coalesce_usecs, priv);
if ((rx_riwt > MAX_DMA_RIWT) || (rx_riwt < MIN_DMA_RIWT))
--
2.34.1
On Tue, May 23, 2023 at 02:19:52AM -0400, Gan Yi Fang wrote:
> The datatype of rx_coalesce_usecs is u32, always larger or equal to zero.
> Previous checking does not include value 0, this patch removes the
> checking to handle the value 0.
>
> Signed-off-by: Gan Yi Fang <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
On Tue, May 23, 2023 at 02:19:52AM -0400, Gan Yi Fang wrote:
> The datatype of rx_coalesce_usecs is u32, always larger or equal to zero.
> Previous checking does not include value 0, this patch removes the
> checking to handle the value 0.
>
> Signed-off-by: Gan Yi Fang <[email protected]>
> ---
> drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> index 35c8dd92d369..6ed0e683b5e0 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> @@ -917,7 +917,7 @@ static int __stmmac_set_coalesce(struct net_device *dev,
> else if (queue >= max_cnt)
> return -EINVAL;
>
> - if (priv->use_riwt && (ec->rx_coalesce_usecs > 0)) {
> + if (priv->use_riwt) {
> rx_riwt = stmmac_usec2riwt(ec->rx_coalesce_usecs, priv);
>
> if ((rx_riwt > MAX_DMA_RIWT) || (rx_riwt < MIN_DMA_RIWT))
This appears to be a user visible ABI change. For the current code, a
value of zero here is ignored, and 0 is returned. With this change, 0
will result in rx_riwt being calculated as 0, which is less than
MIN_DMA_RIWT, so you get -EINVAL returned.
I don't know this uAPI too well. What values are passed to this
function for:
ethtool -C eth24 tx-usecs 42
where you only want to change transmit coalesce? Is rx_usecs 0?
At minimum you need to explain in the commit message: "This change in
behaviour making the value of 0 cause an error is not a problem
because...."
Andrew
---
pw-bot: cr
Hi Andrew,
Thank you for your feedback. I will submit V2 to update the commit message.
The value of rx-usecs will not be affected when the tx-usecs is set. When the command "ethtool -C eth24 tx-usecs 42" is applied, the value of rx-usecs is remaining the same as previously.
Best Regards,
Gan Yi Fang
> -----Original Message-----
> From: Andrew Lunn <[email protected]>
> Sent: Tuesday, May 23, 2023 8:48 PM
> To: Gan, Yi Fang <[email protected]>
> Cc: Giuseppe Cavallaro <[email protected]>; Alexandre Torgue
> <[email protected]>; Jose Abreu <[email protected]>; David S .
> Miller <[email protected]>; Eric Dumazet <[email protected]>; Jakub
> Kicinski <[email protected]>; Paolo Abeni <[email protected]>; Maxime
> Coquelin <[email protected]>; [email protected]; linux-
> [email protected]; [email protected];
> [email protected]; Looi, Hong Aun <[email protected]>; Sit,
> Michael Wei Hong <[email protected]>
> Subject: Re: [PATCH net-next 1/1] net: stmmac: Remove redundant checking for
> rx_coalesce_usecs
>
> On Tue, May 23, 2023 at 02:19:52AM -0400, Gan Yi Fang wrote:
> > The datatype of rx_coalesce_usecs is u32, always larger or equal to zero.
> > Previous checking does not include value 0, this patch removes the
> > checking to handle the value 0.
> >
> > Signed-off-by: Gan Yi Fang <[email protected]>
> > ---
> > drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> > b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> > index 35c8dd92d369..6ed0e683b5e0 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> > @@ -917,7 +917,7 @@ static int __stmmac_set_coalesce(struct net_device
> *dev,
> > else if (queue >= max_cnt)
> > return -EINVAL;
> >
> > - if (priv->use_riwt && (ec->rx_coalesce_usecs > 0)) {
> > + if (priv->use_riwt) {
> > rx_riwt = stmmac_usec2riwt(ec->rx_coalesce_usecs, priv);
> >
> > if ((rx_riwt > MAX_DMA_RIWT) || (rx_riwt <
> MIN_DMA_RIWT))
>
> This appears to be a user visible ABI change. For the current code, a value of
> zero here is ignored, and 0 is returned. With this change, 0 will result in rx_riwt
> being calculated as 0, which is less than MIN_DMA_RIWT, so you get -EINVAL
> returned.
>
> I don't know this uAPI too well. What values are passed to this function for:
>
> ethtool -C eth24 tx-usecs 42
>
> where you only want to change transmit coalesce? Is rx_usecs 0?
>
> At minimum you need to explain in the commit message: "This change in
> behaviour making the value of 0 cause an error is not a problem because...."
>
> Andrew
>
> ---
> pw-bot: cr