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Thu, 28 Mar 2024 15:59:57 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0784020043; Thu, 28 Mar 2024 15:59:55 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2DCDF20040; Thu, 28 Mar 2024 15:59:54 +0000 (GMT) Received: from [9.171.12.209] (unknown [9.171.12.209]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 28 Mar 2024 15:59:54 +0000 (GMT) Message-ID: <1b532020394c6441634a665b7e59427002b4f79f.camel@linux.ibm.com> Subject: Re: [PATCH net 1/1] s390/ism: fix receive message buffer allocation From: Gerd Bayer To: Wenjia Zhang , Wen Gu , Heiko Carstens , pasic@linux.ibm.com, schnelle@linux.ibm.com, Christoph Hellwig Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, Alexandra Winter , Thorsten Winkler , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle Date: Thu, 28 Mar 2024 16:59:53 +0100 In-Reply-To: <20240328154144.272275-2-gbayer@linux.ibm.com> References: <20240328154144.272275-1-gbayer@linux.ibm.com> <20240328154144.272275-2-gbayer@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.50.4 (3.50.4-2.fc39app4) X-TM-AS-GCONF: 00 X-Proofpoint-GUID: unwUFeZI_eZfd4vvsAMzGZxKCAKCjbCe X-Proofpoint-ORIG-GUID: QH6Q4a3q3EJOwu7gRCAQHxwKSWcEPthg Content-Transfer-Encoding: quoted-printable X-Proofpoint-UnRewURL: 0 URL was un-rewritten Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-03-28_15,2024-03-28_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 spamscore=0 clxscore=1011 impostorscore=0 mlxscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 phishscore=0 bulkscore=0 mlxlogscore=664 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2403210000 definitions=main-2403280109 On Thu, 2024-03-28 at 16:41 +0100, Gerd Bayer wrote: > Since [1], dma_alloc_coherent() does not accept requests for GFP_COMP > anymore, even on archs that may be able to fulfill this. > Functionality that > relied on the receive buffer being a compound page broke at that > point: > The SMC-D protocol, that utilizes the ism device driver, passes > receive > buffers to the splice processor in a struct splice_pipe_desc with a > single entry list of struct pages. As the buffer is no longer a > compound > page, the splice processor now rejects requests to handle more than a > page worth of data. >=20 > Replace dma_alloc_coherent() and allocate a buffer with kmalloc() > then > create a DMA map for it with dma_map_page(). Since only receive > buffers > on ISM devices use DMA, qualify the mapping as FROM_DEVICE. > Since ISM devices are available on arch s390, only and on that arch > all > DMA is coherent, there is no need to introduce and export some kind > of > dma_sync_to_cpu() method to be called by the SMC-D protocol layer. >=20 > Analogously, replace dma_free_coherent by a two step dma_unmap_page, > then kfree to free the receive buffer. >=20 > [1] https://lore.kernel.org/all/20221113163535.884299-1-hch@lst.de/ >=20 > Fixes: c08004eede4b ("s390/ism: don't pass bogus GFP_ flags to > dma_alloc_coherent") Late adding Christoph as the "blamed" committer. > Signed-off-by: Gerd Bayer > --- > =C2=A0drivers/s390/net/ism_drv.c | 35 ++++++++++++++++++++++++++--------- > =C2=A01 file changed, 26 insertions(+), 9 deletions(-) >=20 > diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c > index 2c8e964425dc..25911b887e5e 100644 > --- a/drivers/s390/net/ism_drv.c > +++ b/drivers/s390/net/ism_drv.c > @@ -14,6 +14,8 @@ > =C2=A0#include > =C2=A0#include > =C2=A0#include > +#include > +#include > =C2=A0 > =C2=A0#include "ism.h" > =C2=A0 > @@ -292,13 +294,15 @@ static int ism_read_local_gid(struct ism_dev > *ism) > =C2=A0static void ism_free_dmb(struct ism_dev *ism, struct ism_dmb *dmb) > =C2=A0{ > =C2=A0 clear_bit(dmb->sba_idx, ism->sba_bitmap); > - dma_free_coherent(&ism->pdev->dev, dmb->dmb_len, > - =C2=A0 dmb->cpu_addr, dmb->dma_addr); > + dma_unmap_page(&ism->pdev->dev, dmb->dma_addr, dmb->dmb_len, > + =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 DMA_FROM_DEVICE); > + kfree(dmb->cpu_addr); > =C2=A0} > =C2=A0 > =C2=A0static int ism_alloc_dmb(struct ism_dev *ism, struct ism_dmb *dmb) > =C2=A0{ > =C2=A0 unsigned long bit; > + int rc; > =C2=A0 > =C2=A0 if (PAGE_ALIGN(dmb->dmb_len) > dma_get_max_seg_size(&ism- > >pdev->dev)) > =C2=A0 return -EINVAL; > @@ -315,14 +319,27 @@ static int ism_alloc_dmb(struct ism_dev *ism, > struct ism_dmb *dmb) > =C2=A0 =C2=A0=C2=A0=C2=A0 test_and_set_bit(dmb->sba_idx, ism->sba_bitmap)) > =C2=A0 return -EINVAL; > =C2=A0 > - dmb->cpu_addr =3D dma_alloc_coherent(&ism->pdev->dev, dmb- > >dmb_len, > - =C2=A0=C2=A0 &dmb->dma_addr, > - =C2=A0=C2=A0 GFP_KERNEL | __GFP_NOWARN > | > - =C2=A0=C2=A0 __GFP_NOMEMALLOC | > __GFP_NORETRY); > - if (!dmb->cpu_addr) > - clear_bit(dmb->sba_idx, ism->sba_bitmap); > + dmb->cpu_addr =3D kmalloc(dmb->dmb_len, GFP_KERNEL | > __GFP_NOWARN | > + __GFP_COMP | __GFP_NOMEMALLOC | > __GFP_NORETRY); > + if (!dmb->cpu_addr) { > + rc =3D -ENOMEM; > + goto out_bit; > + } > + dmb->dma_addr =3D dma_map_page(&ism->pdev->dev, > + =C2=A0=C2=A0=C2=A0=C2=A0 virt_to_page(dmb->cpu_addr), 0, > + =C2=A0=C2=A0=C2=A0=C2=A0 dmb->dmb_len, DMA_FROM_DEVICE); > + if (dma_mapping_error(&ism->pdev->dev, dmb->dma_addr)) { > + rc =3D -ENOMEM; > + goto out_free; > + } > + > + return 0; > =C2=A0 > - return dmb->cpu_addr ? 0 : -ENOMEM; > +out_free: > + kfree(dmb->cpu_addr); > +out_bit: > + clear_bit(dmb->sba_idx, ism->sba_bitmap); > + return rc; > =C2=A0} > =C2=A0 > =C2=A0int ism_register_dmb(struct ism_dev *ism, struct ism_dmb *dmb,