linux-kernel - Re: [PATCH net-next v7 3/3] net: axienet: Introduce dmaengine support

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]

Date:   Mon, 9 Oct 2023 17:17:56 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     "Pandey, Radhey Shyam" <radhey.shyam.pandey@....com>
Cc:     "davem@...emloft.net" <davem@...emloft.net>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "pabeni@...hat.com" <pabeni@...hat.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "conor+dt@...nel.org" <conor+dt@...nel.org>,
        "Simek, Michal" <michal.simek@....com>,
        "linux@...linux.org.uk" <linux@...linux.org.uk>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "git (AMD-Xilinx)" <git@....com>
Subject: Re: [PATCH net-next v7 3/3] net: axienet: Introduce dmaengine
 support

On Mon, 9 Oct 2023 19:41:35 +0000 Pandey, Radhey Shyam wrote:
> > But somewhere else or just here after printing the warning?  
> 
> There is call to netif_stop_queue(ndev) just before this netdev_warn.
> I copied below for quick reference.
> 
> +	sg_len = skb_shinfo(skb)->nr_frags + 1;
> +	if (!CIRC_SPACE(lp->tx_ring_head, lp->tx_ring_tail, TX_BD_NUM_MAX)) {
> +		netif_stop_queue(ndev);
> +		if (net_ratelimit())
> +			netdev_warn(ndev, "TX ring unexpectedly full\n");
> +		return NETDEV_TX_BUSY;
> +	}
> 
> However, I noticed above check doesn't account for all frags - so will 
> modify the if check to see if available space is less than sg_len. If yes, then 
> stop the queue and return busy , else continue with xmit.

Please take a look at:

https://www.kernel.org/doc/html/next/networking/driver.html#stop-queues-in-advance