linux-kernel - RE: [PATCH] net: fec: allow disable coalescing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID:
 <PAXPR04MB8510C17E1980D456FD9F094F887AA@PAXPR04MB8510.eurprd04.prod.outlook.com>
Date: Thu, 26 Jun 2025 02:36:37 +0000
From: Wei Fang <wei.fang@....com>
To: Jonas Rebmann <jre@...gutronix.de>
CC: "imx@...ts.linux.dev" <imx@...ts.linux.dev>, "netdev@...r.kernel.org"
	<netdev@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "kernel@...gutronix.de"
	<kernel@...gutronix.de>, Shenwei Wang <shenwei.wang@....com>, Clark Wang
	<xiaoning.wang@....com>, Andrew Lunn <andrew+netdev@...n.ch>, "David S.
 Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub
 Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Subject: RE: [PATCH] net: fec: allow disable coalescing

>  static void fec_enet_itr_coal_set(struct net_device *ndev)
>  {
>         struct fec_enet_private *fep = netdev_priv(ndev);
> -       int rx_itr, tx_itr;
> +       int rx_itr = 0, tx_itr = 0;

Since you modified this line, it would be a good idea to change
the type to u32.

> 
> -       /* Must be greater than zero to avoid unpredictable behavior */
> -       if (!fep->rx_time_itr || !fep->rx_pkts_itr ||
> -           !fep->tx_time_itr || !fep->tx_pkts_itr)
> -               return;
> -
> -       /* Select enet system clock as Interrupt Coalescing
> -        * timer Clock Source
> -        */
> -       rx_itr = FEC_ITR_CLK_SEL;
> -       tx_itr = FEC_ITR_CLK_SEL;
> -
> -       /* set ICFT and ICTT */
> -       rx_itr |= FEC_ITR_ICFT(fep->rx_pkts_itr);
> -       rx_itr |= FEC_ITR_ICTT(fec_enet_us_to_itr_clock(ndev,
> fep->rx_time_itr));
> -       tx_itr |= FEC_ITR_ICFT(fep->tx_pkts_itr);
> -       tx_itr |= FEC_ITR_ICTT(fec_enet_us_to_itr_clock(ndev,
> fep->tx_time_itr));
> +       if (fep->rx_time_itr > 0 && fep->rx_pkts_itr > 1) {
> +               /* Select enet system clock as Interrupt Coalescing timer
> Clock Source */
> +               rx_itr = FEC_ITR_CLK_SEL;
> +               rx_itr |= FEC_ITR_EN;

nitpicking: the above two lines can be simplified to one line as below,
but the comment needs to be changed appropriately.

	rx_itr = FEC_ITR_CLK_SEL | FEC_ITR_EN;

> +               rx_itr |= FEC_ITR_ICFT(fep->rx_pkts_itr);
> +               rx_itr |= FEC_ITR_ICTT(fec_enet_us_to_itr_clock(ndev,
> fep->rx_time_itr));
> +       }
> 
> -       rx_itr |= FEC_ITR_EN;
> -       tx_itr |= FEC_ITR_EN;
> +       if (fep->tx_time_itr > 0 && fep->tx_pkts_itr > 1) {
> +               /* Select enet system clock as Interrupt Coalescing timer
> Clock Source */
> +               tx_itr = FEC_ITR_CLK_SEL;
> +               tx_itr |= FEC_ITR_EN;

Same as above