From: Jakub Kicinski <kuba@kernel.org>
To: "Ramsay, Lincoln" <Lincoln.Ramsay@digi.com>
Cc: Florian Westphal <fw@strlen.de>,
Igor Russkikh <irusskikh@marvell.com>,
"David S. Miller" <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Dmitry Bogdanov <dbogdanov@marvell.com>
Subject: Re: [PATCH v4] aquantia: Remove the build_skb path
Date: Sat, 21 Nov 2020 13:23:24 -0800 [thread overview]
Message-ID: <20201121132324.72d79e94@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20201121132204.43f9c4fb@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On Sat, 21 Nov 2020 13:22:04 -0800 Jakub Kicinski wrote:
> On Thu, 19 Nov 2020 23:52:55 +0000 Ramsay, Lincoln wrote:
> > When performing IPv6 forwarding, there is an expectation that SKBs
> > will have some headroom. When forwarding a packet from the aquantia
> > driver, this does not always happen, triggering a kernel warning.
> >
> > aq_ring.c has this code (edited slightly for brevity):
> >
> > if (buff->is_eop && buff->len <= AQ_CFG_RX_FRAME_MAX - AQ_SKB_ALIGN) {
> > skb = build_skb(aq_buf_vaddr(&buff->rxdata), AQ_CFG_RX_FRAME_MAX);
> > } else {
> > skb = napi_alloc_skb(napi, AQ_CFG_RX_HDR_SIZE);
> >
> > There is a significant difference between the SKB produced by these
> > 2 code paths. When napi_alloc_skb creates an SKB, there is a certain
> > amount of headroom reserved. However, this is not done in the
> > build_skb codepath.
> >
> > As the hardware buffer that build_skb is built around does not
> > handle the presence of the SKB header, this code path is being
> > removed and the napi_alloc_skb path will always be used. This code
> > path does have to copy the packet header into the SKB, but it adds
> > the packet data as a frag.
> >
> > Signed-off-by: Lincoln Ramsay <lincoln.ramsay@opengear.com>
>
> I was going to apply as a fix to net and stable but too many small nits
> here to pass. First of all please add a From: line at the beginning of
> the mail which matches the signoff (or use git-send-email, it'll get it
> right).
Ah, one more thing, this is the correct fixes tag, right?
Fixes: 018423e90bee ("net: ethernet: aquantia: Add ring support code")
Please add it right before the signoff line.
next prev parent reply other threads:[~2020-11-21 21:25 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 1:52 [PATCH] aquantia: Reserve space when allocating an SKB Ramsay, Lincoln
2020-11-18 14:02 ` [EXT] " Igor Russkikh
2020-11-19 0:14 ` Ramsay, Lincoln
2020-11-19 5:19 ` Ramsay, Lincoln
2020-11-19 22:01 ` [PATCH] aquantia: Remove the build_skb path Ramsay, Lincoln
2020-11-19 22:07 ` [PATCH v2] " Ramsay, Lincoln
2020-11-19 22:15 ` Florian Westphal
2020-11-19 22:24 ` Ramsay, Lincoln
2020-11-19 22:28 ` Florian Westphal
2020-11-19 22:34 ` [PATCH v3] " Ramsay, Lincoln
2020-11-19 22:49 ` Maciej Fijalkowski
2020-11-20 8:18 ` [EXT] " Igor Russkikh
2020-11-23 19:28 ` Maciej Fijalkowski
2020-11-24 15:26 ` Igor Russkikh
2020-11-19 22:58 ` Florian Westphal
2020-11-19 23:52 ` [PATCH v4] " Ramsay, Lincoln
2020-11-20 0:17 ` Florian Westphal
2020-11-20 0:23 ` Ramsay, Lincoln
2020-11-21 21:22 ` Jakub Kicinski
2020-11-21 21:23 ` Jakub Kicinski [this message]
2020-11-22 22:36 ` Ramsay, Lincoln
2020-11-23 16:42 ` Jakub Kicinski
2020-11-23 21:40 ` [PATCH net v5] " Ramsay, Lincoln
2020-11-24 19:02 ` Jakub Kicinski
2020-11-22 21:55 ` [PATCH v4] " Ramsay, Lincoln
2020-11-20 7:52 ` [EXT] [PATCH] " Igor Russkikh
2020-11-23 4:20 ` Ramsay, Lincoln
2020-11-24 14:29 ` Igor Russkikh
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