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From:   "G, GurucharanX" <gurucharanx.g@intel.com>
To:     Akihiko Odaki <akihiko.odaki@daynix.com>
CC:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Yuri Benditovich" <yuri.benditovich@daynix.com>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Yan Vugenfirer <yan@daynix.com>,
        "intel-wired-lan@lists.osuosl.org" <intel-wired-lan@lists.osuosl.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: RE: [Intel-wired-lan] [PATCH] e1000e: Fix TX dispatch condition
Thread-Topic: [Intel-wired-lan] [PATCH] e1000e: Fix TX dispatch condition
Thread-Index: AQHY4i/wwnBgA5Ygw0OeRm02KRN3h64iX+ew
Date:   Thu, 27 Oct 2022 14:41:33 +0000
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References: <20221013050044.11862-1-akihiko.odaki@daynix.com>
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> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Akihiko Odaki
> Sent: Thursday, October 13, 2022 10:31 AM
> Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Yuri Benditovic=
h
> <yuri.benditovich@daynix.com>; Eric Dumazet <edumazet@google.com>;
> Jakub Kicinski <kuba@kernel.org>; Yan Vugenfirer <yan@daynix.com>; intel-
> wired-lan@lists.osuosl.org; Paolo Abeni <pabeni@redhat.com>; David S.
> Miller <davem@davemloft.net>
> Subject: [Intel-wired-lan] [PATCH] e1000e: Fix TX dispatch condition
>=20
> e1000_xmit_frame is expected to stop the queue and dispatch frames to
> hardware if there is not sufficient space for the next frame in the buffe=
r, but
> sometimes it failed to do so because the estimated maxmium size of frame
> was wrong. As the consequence, the later invocation of e1000_xmit_frame
> failed with NETDEV_TX_BUSY, and the frame in the buffer remained forever,
> resulting in a watchdog failure.
>=20
> This change fixes the estimated size by making it match with the conditio=
n for
> NETDEV_TX_BUSY. Apparently, the old estimation failed to account for the
> following lines which determines the space requirement for not causing
> NETDEV_TX_BUSY:
> >	/* reserve a descriptor for the offload context */
> >	if ((mss) || (skb->ip_summed =3D=3D CHECKSUM_PARTIAL))
> >		count++;
> >	count++;
> >
> >	count +=3D DIV_ROUND_UP(len, adapter->tx_fifo_limit);
>=20
> This issue was found with http-stress02 test included in Linux Test Proje=
ct
> 20220930.
>=20
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>  drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>=20

Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Int=
el)