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[146.241.247.213]) by smtp.gmail.com with ESMTPSA id k41-20020a05600c1ca900b004156c501e24sm1755494wms.12.2024.04.04.01.13.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Apr 2024 01:13:32 -0700 (PDT) Message-ID: <68ce59955f13751b3ced82cd557b069ed397085a.camel@redhat.com> Subject: Re: [PATCH net 1/1] s390/ism: fix receive message buffer allocation From: Paolo Abeni To: Gerd Bayer , Wenjia Zhang , Wen Gu , Heiko Carstens , pasic@linux.ibm.com, schnelle@linux.ibm.com Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, Alexandra Winter , Thorsten Winkler , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Christoph Hellwig Date: Thu, 04 Apr 2024 10:13:30 +0200 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> Autocrypt: addr=pabeni@redhat.com; prefer-encrypt=mutual; keydata=mQINBGISiDUBEAC5uMdJicjm3ZlWQJG4u2EU1EhWUSx8IZLUTmEE8zmjPJFSYDcjtfGcbzLPb63BvX7FADmTOkO7gwtDgm501XnQaZgBUnCOUT8qv5MkKsFH20h1XJyqjPeGM55YFAXc+a4WD0YyO5M0+KhDeRLoildeRna1ey944VlZ6Inf67zMYw9vfE5XozBtytFIrRyGEWkQwkjaYhr1cGM8ia24QQVQid3P7SPkR78kJmrT32sGk+TdR4YnZzBvVaojX4AroZrrAQVdOLQWR+w4w1mONfJvahNdjq73tKv51nIpu4SAC1Zmnm3x4u9r22mbMDr0uWqDqwhsvkanYmn4umDKc1ZkBnDIbbumd40x9CKgG6ogVlLYeJa9WyfVMOHDF6f0wRjFjxVoPO6p/ZDkuEa67KCpJnXNYipLJ3MYhdKWBZw0xc3LKiKc+nMfQlo76T/qHMDfRMaMhk+L8gWc3ZlRQFG0/Pd1pdQEiRuvfM5DUXDo/YOZLV0NfRFU9SmtIPhbdm9cV8Hf8mUwubihiJB/9zPvVq8xfiVbdT0sPzBtxW0fXwrbFxYAOFvT0UC2MjlIsukjmXOUJtdZqBE3v3Jf7VnjNVj9P58+MOx9iYo8jl3fNd7biyQWdPDfYk9ncK8km4skfZQIoUVqrWqGDJjHO1W9CQLAxkfOeHrmG29PK9tHIwARAQABtB9QYW9sbyBBYmVuaSA8cGFiZW5pQHJlZGhhdC5jb20+iQJSBBMBCAA8FiEEg1AjqC77wbdLX2LbKSR5jcyPE6QFAmISiDUCGwMFCwkIBwIDIgIBBhUKCQgLAgQWAgMBAh4HAheAAAoJECkkeY3MjxOkJSYQAJcc6MTsuFxYdYZkeWjW//zbD3ApRHzpNlHLVSuJqHr9/aDS+tyszgS8jj9MiqALzgq4iZbg 7ZxN9ZsDL38qVIuFkSpgMZCiUHdxBC11J8nbBSLlpnc924UAyr5XrGA99 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 iWjoCy8L35zPqR5TV+f5WR5hTVCqmLHSgm1jxwKhPg9L+GfuE4d0SWd84y 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 sD2W1U7eyLdm/jCgticGDsRtweytsgCSYfbz0gdgUuL3EBYN3JLbAU+UZpy 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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 th= at > 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") > Signed-off-by: Gerd Bayer > --- > drivers/s390/net/ism_drv.c | 35 ++++++++++++++++++++++++++--------- > 1 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 @@ > #include > #include > #include > +#include > +#include > =20 > #include "ism.h" > =20 > @@ -292,13 +294,15 @@ static int ism_read_local_gid(struct ism_dev *ism) > static void ism_free_dmb(struct ism_dev *ism, struct ism_dmb *dmb) > { > clear_bit(dmb->sba_idx, ism->sba_bitmap); > - dma_free_coherent(&ism->pdev->dev, dmb->dmb_len, > - dmb->cpu_addr, dmb->dma_addr); > + dma_unmap_page(&ism->pdev->dev, dmb->dma_addr, dmb->dmb_len, > + DMA_FROM_DEVICE); > + kfree(dmb->cpu_addr); > } > =20 > static int ism_alloc_dmb(struct ism_dev *ism, struct ism_dmb *dmb) > { > unsigned long bit; > + int rc; > =20 > if (PAGE_ALIGN(dmb->dmb_len) > dma_get_max_seg_size(&ism->pdev->dev)) > return -EINVAL; > @@ -315,14 +319,27 @@ static int ism_alloc_dmb(struct ism_dev *ism, struc= t ism_dmb *dmb) > test_and_set_bit(dmb->sba_idx, ism->sba_bitmap)) > return -EINVAL; > =20 > - dmb->cpu_addr =3D dma_alloc_coherent(&ism->pdev->dev, dmb->dmb_len, > - &dmb->dma_addr, > - GFP_KERNEL | __GFP_NOWARN | > - __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); Out of sheer ignorance on my side, the __GFP_COMP flag looks suspicious here. I *think* that is relevant only for the page allocator.=20 Why can't you use get_free_pages() (or similar) here? (possibly rounding up to the relevant page_aligned size).=20 Thanks! Paolo