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[5.173.65.115]) by smtp.googlemail.com with ESMTPSA id h5-20020a0564020e8500b00458a03203b1sm777561eda.31.2022.11.17.09.19.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Nov 2022 09:19:42 -0800 (PST) From: Lukasz Wiecaszek X-Google-Original-From: Lukasz Wiecaszek To: Gerd Hoffmann Cc: Dmitry Osipenko , Lukasz Wiecaszek , =?UTF-8?q?Christian=20K=C3=B6nig?= , Sumit Semwal , dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH v5] udmabuf: add vmap and vunmap methods to udmabuf_ops Date: Thu, 17 Nov 2022 18:18:09 +0100 Message-Id: <20221117171810.75637-1-lukasz.wiecaszek@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The reason behind that patch is associated with videobuf2 subsystem (or more genrally with v4l2 framework) and user created dma buffers (udmabuf). In some circumstances when dealing with V4L2_MEMORY_DMABUF buffers videobuf2 subsystem wants to use dma_buf_vmap() method on the attached dma buffer. As udmabuf does not have .vmap operation implemented, such dma_buf_vmap() natually fails. videobuf2_common: __vb2_queue_alloc: allocated 3 buffers, 1 plane(s) each videobuf2_common: __prepare_dmabuf: buffer for plane 0 changed videobuf2_common: __prepare_dmabuf: failed to map dmabuf for plane 0 videobuf2_common: __buf_prepare: buffer preparation failed: -14 The patch itself seems to be strighforward. It adds implementation of .vmap and .vunmap methods to 'struct dma_buf_ops udmabuf_ops'. .vmap method itself uses vm_map_ram() to map pages linearly into the kernel virtual address space. .vunmap removes mapping created earlier by .vmap. All locking and 'vmapping counting' is done in dma_buf.c so it seems to be redundant/unnecessary in .vmap/.vunmap. Reviewed-by: Dmitry Osipenko Acked-by: Christian K=C3=B6nig Signed-off-by: Lukasz Wiecaszek --- v1: https://lore.kernel.org/linux-media/202211120352.G7WPASoP-lkp@intel.com= /T/#t v2: https://lore.kernel.org/linux-media/20221114052944.GA7264@thinkpad-p72/= T/#t v3: https://lore.kernel.org/linux-media/4f92e95f-a0dc-4eac-4c08-0df85de78ae= 7@collabora.com/T/#t v4: https://lore.kernel.org/linux-media/970e798d-ea26-5e1e-ace8-7915a866f7c= 7@collabora.com/T/#t v4 -> v5: Added Acked-by and Reviewed-by to the commit message v3 -> v4: Removed line/info 'reported by kernel test robot' v2 -> v3: Added .vunmap to 'struct dma_buf_ops udmabuf_ops' v1 -> v2: Patch prepared and tested against 6.1.0-rc2+ drivers/dma-buf/udmabuf.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 283816fbd72f..740d6e426ee9 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -13,6 +13,8 @@ #include #include #include +#include +#include =20 static int list_limit =3D 1024; module_param(list_limit, int, 0644); @@ -60,6 +62,30 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_a= rea_struct *vma) return 0; } =20 +static int vmap_udmabuf(struct dma_buf *buf, struct iosys_map *map) +{ + struct udmabuf *ubuf =3D buf->priv; + void *vaddr; + + dma_resv_assert_held(buf->resv); + + vaddr =3D vm_map_ram(ubuf->pages, ubuf->pagecount, -1); + if (!vaddr) + return -EINVAL; + + iosys_map_set_vaddr(map, vaddr); + return 0; +} + +static void vunmap_udmabuf(struct dma_buf *buf, struct iosys_map *map) +{ + struct udmabuf *ubuf =3D buf->priv; + + dma_resv_assert_held(buf->resv); + + vm_unmap_ram(map->vaddr, ubuf->pagecount); +} + static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *b= uf, enum dma_data_direction direction) { @@ -162,6 +188,8 @@ static const struct dma_buf_ops udmabuf_ops =3D { .unmap_dma_buf =3D unmap_udmabuf, .release =3D release_udmabuf, .mmap =3D mmap_udmabuf, + .vmap =3D vmap_udmabuf, + .vunmap =3D vunmap_udmabuf, .begin_cpu_access =3D begin_cpu_udmabuf, .end_cpu_access =3D end_cpu_udmabuf, }; --=20 2.25.1