Re: [gentoo-dev] linux/dma-buf.h mysteriously missing

[Mike Gilbert]

On Wed, Mar 29, 2017 at 12:34 PM, Paweł Hajdan, Jr.
<phajdan.jr@g.o> wrote:
> I was packaging chromium-59.0.3053.3 . I worked around the problem
> described here, but I'd like to find the right long term solution.
>
> I was hitting the following compile error:
>
> ../../ui/gfx/linux/client_native_pixmap_dmabuf.cc:39:27: fatal error:
> linux/dma-buf.h: No such file or directory
>  #include <linux/dma-buf.h>
>
> Despite having sys-kernel/linux-headers-4.10 installed, I do not have
> that header. Interestingly, it is present in the tarball
> (gentoo-headers-base-4.10.tar.xz), but doesn't seem to get installed.
>
> This is the workaround I applied:
> <https://gitweb.gentoo.org/repo/gentoo.git/tree/www-client/chromium/files/chromium-dma-buf-r1.patch?id=f3d721fbb4127f17e836a1842cfdd2bf76f0d398>
>
> This is part of the chromium code in question:
>
> <https://cs.chromium.org/chromium/src/ui/gfx/linux/client_native_pixmap_dmabuf.cc?q=dma-buf.h+package:%5Echromium$&l=39&dr=C>
>
> #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0)
> #include <linux/types.h>
>
> struct local_dma_buf_sync {
>   __u64 flags;
> };
>
> #define LOCAL_DMA_BUF_SYNC_READ (1 << 0)
> #define LOCAL_DMA_BUF_SYNC_WRITE (2 << 0)
> #define LOCAL_DMA_BUF_SYNC_RW \
>   (LOCAL_DMA_BUF_SYNC_READ | LOCAL_DMA_BUF_SYNC_WRITE)
> #define LOCAL_DMA_BUF_SYNC_START (0 << 2)
> #define LOCAL_DMA_BUF_SYNC_END (1 << 2)
>
> #define LOCAL_DMA_BUF_BASE 'b'
> #define LOCAL_DMA_BUF_IOCTL_SYNC \
>   _IOW(LOCAL_DMA_BUF_BASE, 0, struct local_dma_buf_sync)
>
> #else
> #include <linux/dma-buf.h>
> #endif

It seems the file was not added to include/uapi/linux/Kbuild. This was
likely an oversight by the kernel developer who added the header file.

I would suggest filing a bug.