Re: [PATCH] drm/virtio: Use vmalloc for command buffer allocations.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Aug 30, 2019 at 4:16 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
>
>   Hi,
>
> > > > -     kfree(vbuf->data_buf);
> > > > +     kvfree(vbuf->data_buf);
> > >
> > > if (is_vmalloc_addr(vbuf->data_buf)) ...
> > >
> > > needed here I gues?
> > >
> >
> > kvfree() handles vmalloc/kmalloc/kvmalloc internally by doing that check.
>
> Ok.
>
> > - videobuf_vmalloc_to_sg in drivers/media/v4l2-core/videobuf-dma-sg.c,
> > assumes contiguous array of scatterlist and that the buffer being converted
> > is page aligned
>
> Well, vmalloc memory _is_ page aligned.
>
> sg_alloc_table_from_pages() does alot of what you need, you just need a
> small loop around vmalloc_to_page() create a struct page array
> beforehand.
>
> Completely different approach: use get_user_pages() and don't copy the
> execbuffer at all.
It would be really nice if execbuffer does not copy.

The user space owns the buffer and may overwrite the contents
immediately after the ioctl.  We also need a flag to indicate that the
ownership of the buffer is transferred to the kernel.




>
> cheers,
>   Gerd
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization



[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux