Re: [PATCH] dma-buf: add reference counting for exporter module

[Daniel Vetter]

On Wed, Aug 08, 2012 at 03:53:10PM +0200, Tomasz Stanislawski wrote:
> Hi Laurent,
> 
> On 08/08/2012 03:35 PM, Laurent Pinchart wrote:
> > Hi Tomasz,
> > 
> > Thanks for the patch.
> > 
> > On Wednesday 08 August 2012 12:17:41 Tomasz Stanislawski wrote:
> >> This patch adds reference counting on a module that exports dma-buf and
> >> implements its operations. This prevents the module from being unloaded
> >> while DMABUF file is in use.
> >>
> >> Signed-off-by: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx>
> >> ---
> >>  Documentation/dma-buf-sharing.txt          |    3 ++-
> >>  drivers/base/dma-buf.c                     |   10 +++++++++-
> >>  drivers/gpu/drm/exynos/exynos_drm_dmabuf.c |    1 +
> >>  drivers/gpu/drm/i915/i915_gem_dmabuf.c     |    1 +
> >>  drivers/gpu/drm/nouveau/nouveau_prime.c    |    1 +
> >>  drivers/gpu/drm/radeon/radeon_prime.c      |    1 +
> >>  drivers/staging/omapdrm/omap_gem_dmabuf.c  |    1 +
> >>  include/linux/dma-buf.h                    |    2 ++
> >>  8 files changed, 18 insertions(+), 2 deletions(-)
> >>
> [snip]
> 
> >> @@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct
> >> dma_buf_ops *ops, struct file *file;
> >>
> >>  	if (WARN_ON(!priv || !ops
> >> +			  || !ops->owner
> 
> Thank you for spotting this.
> I didn'y know that try_get_module returned true is module was NULL.
> 
> BTW. Is it worth to add ".owner = THIS_MODULE," to all dma_buf
> exporters in this patch?

Yeah, I think that makes sense. Otherwise it might get lost somewhere,
i.e. you can smash my Ack on this.
-Daniel
-- 
Daniel Vetter
Mail: daniel@xxxxxxxx
Mobile: +41 (0)79 365 57 48
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