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From:   Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [PATCH] drm/virtio: Use vmalloc for command buffer allocations.
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> > 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.

Oh, right.  The exec ioctl doesn't block.  So this doesn't work (breaks
userspace abi).  Scratch the idea then.

> We also need a flag to indicate that the
> ownership of the buffer is transferred to the kernel.

Yes, with an additional flag for the changed behavior it could work.

cheers,
  Gerd