Hi,

On Wed, Oct 16, 2019 at 10:31:31AM +0300, Alexander Lobakin wrote:

David Miller wrote 16.10.2019 04:16:

quoted

From: Alexander Lobakin <redacted>
Date: Mon, 14 Oct 2019 11:00:33 +0300

quoted

Commit 323ebb61e32b4 ("net: use listified RX for handling GRO_NORMAL
skbs") made use of listified skb processing for the users of
napi_gro_frags().
The same technique can be used in a way more common napi_gro_receive()
to speed up non-merged (GRO_NORMAL) skbs for a wide range of drivers
including gro_cells and mac80211 users.
This slightly changes the return value in cases where skb is being
dropped by the core stack, but it seems to have no impact on related
drivers' functionality.
gro_normal_batch is left untouched as it's very individual for every
single system configuration and might be tuned in manual order to
achieve an optimal performance.

Signed-off-by: Alexander Lobakin <redacted>
Acked-by: Edward Cree <redacted>

Applied, thank you.

David, Edward, Eric, Ilias,
thank you for your time.

Regards,
ᚷ ᛖ ᚢ ᚦ ᚠ ᚱ

I am very sorry to be the bearer of bad news. It appears that this
commit is causing a regression in Linux 5.4.0-rc8-next-20191122,
preventing me from connecting to Wi-Fi networks. I have a Dell XPS 9370
(Intel Core i7-8650U) with Intel Wireless 8265 [8086:24fd].

I did a bisect, and this commit was named the culprit. I then applied
the reverse patch on another clone of Linux next-20191122, and it
started working.

6570bc79c0dfff0f228b7afd2de720fb4e84d61d
net: core: use listified Rx for GRO_NORMAL in napi_gro_receive()

You can see more at the bug report I filed at [0].

[0]
https://bugzilla.kernel.org/show_bug.cgi?id=205647

I called on others at [0] to try to reproduce this - you should not pull 
a patch because of a single reporter - as I could be wrong.

Please let me know if you want me to give more debugging information or 
test any potential fixes. I am happy to help to fix this. :)

Kind regards,
Nicholas Johnson