From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7776C4338F for ; Wed, 4 Aug 2021 09:45:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9176960F58 for ; Wed, 4 Aug 2021 09:45:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235527AbhHDJpg (ORCPT ); Wed, 4 Aug 2021 05:45:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237143AbhHDJpg (ORCPT ); Wed, 4 Aug 2021 05:45:36 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1461C061799 for ; Wed, 4 Aug 2021 02:45:23 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mBDSg-000866-Ng; Wed, 04 Aug 2021 11:45:18 +0200 Received: from pengutronix.de (unknown [IPv6:2a02:810a:8940:aa0:e44:2d7c:bf4a:7b36]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: mkl-all@blackshift.org) by smtp.blackshift.org (Postfix) with ESMTPSA id A5FE5660744; Wed, 4 Aug 2021 09:45:16 +0000 (UTC) Date: Wed, 4 Aug 2021 11:45:15 +0200 From: Marc Kleine-Budde To: Dario Binacchi Cc: linux-kernel@vger.kernel.org, Gianluca Falavigna , Andrew Lunn , "David S. Miller" , Jakub Kicinski , Oliver Hartkopp , Vincent Mailhol , Wolfgang Grandegger , linux-can@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [RESEND PATCH 4/4] can: c_can: cache frames to operate as a true FIFO Message-ID: <20210804094515.ariv7d24t2i4hic5@pengutronix.de> References: <20210725161150.11801-1-dariobin@libero.it> <20210725161150.11801-5-dariobin@libero.it> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="vdeu2tms3hj5egqq" Content-Disposition: inline In-Reply-To: <20210725161150.11801-5-dariobin@libero.it> X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-can@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org --vdeu2tms3hj5egqq Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 25.07.2021 18:11:50, Dario Binacchi wrote: > diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h > index 8fe7e2138620..fc499a70b797 100644 > --- a/drivers/net/can/c_can/c_can.h > +++ b/drivers/net/can/c_can/c_can.h > @@ -200,6 +200,7 @@ struct c_can_priv { > atomic_t sie_pending; > unsigned long tx_dir; > int last_status; > + spinlock_t tx_lock; What does the spin lock protect? > struct c_can_tx_ring tx; > u16 (*read_reg)(const struct c_can_priv *priv, enum reg index); > void (*write_reg)(const struct c_can_priv *priv, enum reg index, u16 va= l); > @@ -236,4 +237,9 @@ static inline u8 c_can_get_tx_tail(const struct c_can= _tx_ring *ring) > return ring->tail & (ring->obj_num - 1); > } > =20 > +static inline u8 c_can_get_tx_free(const struct c_can_tx_ring *ring) > +{ > + return ring->obj_num - (ring->head - ring->tail); > +} > + > #endif /* C_CAN_H */ > diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c= _can_main.c > index 451ac9a9586a..4c061fef002c 100644 > --- a/drivers/net/can/c_can/c_can_main.c > +++ b/drivers/net/can/c_can/c_can_main.c > @@ -427,20 +427,6 @@ static void c_can_setup_receive_object(struct net_de= vice *dev, int iface, > c_can_object_put(dev, iface, obj, IF_COMM_RCV_SETUP); > } > =20 > -static u8 c_can_get_tx_free(const struct c_can_tx_ring *ring) > -{ > - u8 head =3D c_can_get_tx_head(ring); > - u8 tail =3D c_can_get_tx_tail(ring); > - > - /* This is not a FIFO. C/D_CAN sends out the buffers > - * prioritized. The lowest buffer number wins. > - */ > - if (head < tail) > - return 0; > - > - return ring->obj_num - head; > -} > - > static bool c_can_tx_busy(const struct c_can_priv *priv, > const struct c_can_tx_ring *tx_ring) > { > @@ -470,7 +456,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *s= kb, > struct can_frame *frame =3D (struct can_frame *)skb->data; > struct c_can_priv *priv =3D netdev_priv(dev); > struct c_can_tx_ring *tx_ring =3D &priv->tx; > - u32 idx, obj; > + u32 idx, obj, cmd =3D IF_COMM_TX; > =20 > if (can_dropped_invalid_skb(dev, skb)) > return NETDEV_TX_OK; > @@ -483,7 +469,11 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *= skb, > if (c_can_get_tx_free(tx_ring) =3D=3D 0) > netif_stop_queue(dev); > =20 > - obj =3D idx + priv->msg_obj_tx_first; > + spin_lock_bh(&priv->tx_lock); What does the spin_lock protect? The ndo_start_xmit function is properly serialized by the networking core. Otherwise the patch looks good! Marc --=20 Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | --vdeu2tms3hj5egqq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEK3kIWJt9yTYMP3ehqclaivrt76kFAmEKYagACgkQqclaivrt 76koYwf/VB746DM0v/+iyR3r8TdJsKJEJp5x3d/t6SQf6kHjdOnXF/v3espWwPKF 44FFrD/LkOx51pxxCV753LtpgGn34eQPcVCLSm8QItkFyB1Am5/wZ9E1hIkQ4cnw hREw9ClpB5bDlKIHYfAo6qTFCqokuZFz+1gSdmRA6oPTQBAeVWCU7OzmJjMFeVau mKAp5GcNz5YO3x/QEOEfqCemWFT9WYDzxaS7c3w2Mzu9yesGfzJRSjRQ6gGcP5hE 3TVcQdyegZEKWhHrehL7YxtHF8Y6HYxvZypTDt78gvQx2eFQiME3bHIIM2s5wdFP wGBfVGU/Uipg753+1k/9SgEUj9/ZUQ== =N0WF -----END PGP SIGNATURE----- --vdeu2tms3hj5egqq--