From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38DD520F88 for ; Fri, 21 Jul 2023 19:07:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0605C433C8; Fri, 21 Jul 2023 19:07:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689966451; bh=Dm0EymO5U40dGN8mbGbuOS3pHyM1mO+KA6k4miuh5PA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jRxuxztCPrJdESF3igekiLchahuhqGxE+OfragQkeOznO+Mfhk+W+XUWQqcLSq1og 093H8GV94ChbNmsRWIuqXTgKxwbvINluDg4If5bBOk8buryxzZUrUewI9jbNRtzxJY YREsWR5YQeeUCHF4GNcLXFUBkF4GCc29jczfJLDc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Linus Walleij , Pawel Dembicki , Vladimir Oltean , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 320/532] net: dsa: vsc73xx: fix MTU configuration Date: Fri, 21 Jul 2023 18:03:44 +0200 Message-ID: <20230721160631.773427428@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160614.695323302@linuxfoundation.org> References: <20230721160614.695323302@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Pawel Dembicki [ Upstream commit 3cf62c8177adb0db9e15c8b898c44f997acf3ebf ] Switch in MAXLEN register stores the maximum size of a data frame. The MTU size is 18 bytes smaller than the frame size. The current settings are causing problems with packet forwarding. This patch fixes the MTU settings to proper values. Fixes: fb77ffc6ec86 ("net: dsa: vsc73xx: make the MTU configurable") Reviewed-by: Linus Walleij Signed-off-by: Pawel Dembicki Reviewed-by: Vladimir Oltean Link: https://lore.kernel.org/r/20230628194327.1765644-1-paweldembicki@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/dsa/vitesse-vsc73xx-core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c index a4b1447ff0557..0c0bc78b1788e 100644 --- a/drivers/net/dsa/vitesse-vsc73xx-core.c +++ b/drivers/net/dsa/vitesse-vsc73xx-core.c @@ -1025,17 +1025,17 @@ static int vsc73xx_change_mtu(struct dsa_switch *ds, int port, int new_mtu) struct vsc73xx *vsc = ds->priv; return vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, - VSC73XX_MAXLEN, new_mtu); + VSC73XX_MAXLEN, new_mtu + ETH_HLEN + ETH_FCS_LEN); } /* According to application not "VSC7398 Jumbo Frames" setting - * up the MTU to 9.6 KB does not affect the performance on standard + * up the frame size to 9.6 KB does not affect the performance on standard * frames. It is clear from the application note that * "9.6 kilobytes" == 9600 bytes. */ static int vsc73xx_get_max_mtu(struct dsa_switch *ds, int port) { - return 9600; + return 9600 - ETH_HLEN - ETH_FCS_LEN; } static const struct dsa_switch_ops vsc73xx_ds_ops = { -- 2.39.2