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x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/ex0Iw2w7PZxxqHuvJIb/PVl"; protocol="application/pgp-signature"; micalg=pgp-sha512 X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250515_225410_567003_C6537C4C X-CRM114-Status: GOOD ( 35.02 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --Sig_/ex0Iw2w7PZxxqHuvJIb/PVl Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi Paolo, > Hi Paolo, >=20 > > On 5/4/25 4:55 PM, Lukasz Majewski wrote: =20 > > > + /* This does 16 byte alignment, exactly what we > > > need. > > > + * The packet length includes FCS, but we don't > > > want to > > > + * include that when passing upstream as it > > > messes up > > > + * bridging applications. > > > + */ > > > + skb =3D netdev_alloc_skb(pndev, pkt_len + > > > NET_IP_ALIGN); > > > + if (unlikely(!skb)) { > > > + dev_dbg(&fep->pdev->dev, > > > + "%s: Memory squeeze, dropping > > > packet.\n", > > > + pndev->name); > > > + pndev->stats.rx_dropped++; > > > + goto err_mem; > > > + } else { > > > + skb_reserve(skb, NET_IP_ALIGN); > > > + skb_put(skb, pkt_len); /* Make room > > > */ > > > + skb_copy_to_linear_data(skb, data, > > > pkt_len); > > > + skb->protocol =3D eth_type_trans(skb, > > > pndev); > > > + napi_gro_receive(&fep->napi, skb); > > > + } > > > + > > > + bdp->cbd_bufaddr =3D > > > dma_map_single(&fep->pdev->dev, data, > > > + > > > bdp->cbd_datlen, > > > + > > > DMA_FROM_DEVICE); > > > + if (unlikely(dma_mapping_error(&fep->pdev->dev, > > > + > > > bdp->cbd_bufaddr))) { > > > + dev_err(&fep->pdev->dev, > > > + "Failed to map descriptor rx > > > buffer\n"); > > > + pndev->stats.rx_errors++; > > > + pndev->stats.rx_dropped++; > > > + dev_kfree_skb_any(skb); > > > + goto err_mem; > > > + } =20 > >=20 > > This is doing the mapping and ev. dropping the skb _after_ pushing > > the skb up the stack, you must attempt the mapping first. =20 >=20 > I've double check it - the code seems to be correct. >=20 > This code is a part of mtip_switch_rx() function, which handles > receiving data. >=20 > First, on probe, the initial dma memory is mapped for MTIP received > data. >=20 > When we receive data, it is processed and afterwards it is "pushed" up > to the network stack. >=20 > As a last step we do map memory for next, incoming data and leave the > function. >=20 > Hence, IMHO, the order is OK and this part shall be left as is. Is the explanation sufficient? >=20 > > =20 > > > +static void mtip_free_buffers(struct net_device *dev) > > > +{ > > > + struct mtip_ndev_priv *priv =3D netdev_priv(dev); > > > + struct switch_enet_private *fep =3D priv->fep; > > > + struct sk_buff *skb; > > > + struct cbd_t *bdp; > > > + int i; > > > + > > > + bdp =3D fep->rx_bd_base; > > > + for (i =3D 0; i < RX_RING_SIZE; i++) { > > > + skb =3D fep->rx_skbuff[i]; > > > + > > > + if (bdp->cbd_bufaddr) > > > + dma_unmap_single(&fep->pdev->dev, > > > bdp->cbd_bufaddr, > > > + MTIP_SWITCH_RX_FRSIZE, > > > + DMA_FROM_DEVICE); > > > + if (skb) > > > + dev_kfree_skb(skb); =20 > >=20 > > I suspect that on error paths mtip_free_buffers() can be invoked > > multiple consecutive times with any successful allocation in > > between: skb will be freed twice. Likely you need to clear > > fep->rx_skbuff[i] here. =20 >=20 > +1 - I will add it with v12. >=20 > >=20 > > Side note: this patch is way too big for a proper review: you need > > to break it in multiple smaller ones, introducing the basic features > > separately. > >=20 > > Cheers, > >=20 > > Paolo > > =20 >=20 >=20 >=20 >=20 > Best regards, >=20 > Lukasz Majewski >=20 > -- >=20 > DENX Software Engineering GmbH, Managing Director: Erika Unter > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: > lukma@denx.de Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Erika Unter HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de --Sig_/ex0Iw2w7PZxxqHuvJIb/PVl Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEgAyFJ+N6uu6+XupJAR8vZIA0zr0FAmgm0voACgkQAR8vZIA0 zr1KMwf+LbqivlaOayX4KF7BX15t/6+4VtMYl0vfPvtkhJUk16KHiMdq8jOJgd1a mEMSCZbdP79VOHquqMUl4dhBBt5pxa9HvHNEprTYncHrAGptXNbLkXtYzW0FCa4g p9/ajwh6N/Q7vl1sc41w5b48sTt1inLufkbRnSZqrW+J4eTLIzXmjJCCpot2zKgr nN8j4gzHwd+auHQkCP3yGhWb9Vxu+F1OAKcw5ChUuMYHw7IuJfTG5EF335HyPY2D NZXKP56M+xsXOdGd4jLXKrr56wiBogIThnfvaBIJBDI8mjAJN23QWsIh/RuNz5FG 0gaOjQiU1Jb2i6tJC4Vk7PP6CGVDJQ== =2uYa -----END PGP SIGNATURE----- --Sig_/ex0Iw2w7PZxxqHuvJIb/PVl--