Re: [PATCH v2 1/1] drm: add kernel doc for exported gem dmabuf_ops

[Daniel Vetter <daniel-/w4YWyX8dFk@public.gmane.org>]

On Tue, Feb 20, 2018 at 03:46:51PM +0000, Li, Samuel wrote:
> > ./drivers/gpu/drm/drm_prime.c:342: warning: Function parameter or
> > member 'attach' not described in 'drm_gem_unmap_dma_buf'
> > ./drivers/gpu/drm/drm_prime.c:342: warning: Function parameter or
> > member 'sgt' not described in 'drm_gem_unmap_dma_buf'
> > ./drivers/gpu/drm/drm_prime.c:342: warning: Function parameter or
> > member 'dir' not described in 'drm_gem_unmap_dma_buf'
> ...
> 
> Actually I tested. Those parameters are left out on purpose since they are empty functions so far.

Can you pls add dummy explanations? I know it's somewhat silly, but when
there's lots of warnings it's much harder to spot new ones. Docs are
sometimes just plain boring rote work :-/

Thanks, Daniel

> 
> Regards,
> Samuel Li
> 
> > -----Original Message-----
> > From: Daniel Vetter [mailto:daniel.vetter@ffwll.ch] On Behalf Of Daniel
> > Vetter
> > Sent: Tuesday, February 20, 2018 10:13 AM
> > To: Li, Samuel <Samuel.Li@amd.com>
> > Cc: Daniel Vetter <daniel@ffwll.ch>; Koenig, Christian
> > <Christian.Koenig@amd.com>; amd-gfx@lists.freedesktop.org; dri-
> > devel@lists.freedesktop.org
> > Subject: Re: [PATCH v2 1/1] drm: add kernel doc for exported gem
> > dmabuf_ops
> > 
> > On Tue, Jan 30, 2018 at 04:01:23PM +0000, Li, Samuel wrote:
> > >
> > > Alex helped push this into drm-tip,
> > > https://cgit.freedesktop.org/drm/drm-
> > tip/commit/drivers/gpu/drm?id=f7a
> > > 71b0cf9e36c1b0edbfe89ce028a01164b864d
> > >
> > > Thanks,
> > > Samuel Li
> > >
> > >
> > > > -----Original Message-----
> > > > From: Daniel Vetter [mailto:daniel.vetter@ffwll.ch] On Behalf Of
> > > > Daniel Vetter
> > > > Sent: Tuesday, January 30, 2018 4:33 AM
> > > > To: Koenig, Christian <Christian.Koenig@amd.com>
> > > > Cc: Li, Samuel <Samuel.Li@amd.com>; amd-gfx@lists.freedesktop.org;
> > > > dri- devel@lists.freedesktop.org
> > > > Subject: Re: [PATCH v2 1/1] drm: add kernel doc for exported gem
> > > > dmabuf_ops
> > > >
> > > > On Fri, Jan 19, 2018 at 09:51:20AM +0100, Christian König wrote:
> > > > > Am 18.01.2018 um 22:44 schrieb Samuel Li:
> > > > > > Signed-off-by: Samuel Li <Samuel.Li@amd.com>
> > > > > > Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > >
> > > > Thanks for updating the docs.
> > > > >
> > > > > Reviewed-by: Christian König <christian.koenig@amd.com>
> > > >
> > > > I'm assuming you'll als push this one.
> > 
> > I just noticed that fairly obviously this wasn't tested when writing:
> > 
> > ./drivers/gpu/drm/drm_prime.c:342: warning: Function parameter or
> > member 'attach' not described in 'drm_gem_unmap_dma_buf'
> > ./drivers/gpu/drm/drm_prime.c:342: warning: Function parameter or
> > member 'sgt' not described in 'drm_gem_unmap_dma_buf'
> > ./drivers/gpu/drm/drm_prime.c:342: warning: Function parameter or
> > member 'dir' not described in 'drm_gem_unmap_dma_buf'
> > ./drivers/gpu/drm/drm_prime.c:438: warning: Function parameter or
> > member 'dma_buf' not described in 'drm_gem_dmabuf_kmap_atomic'
> > ./drivers/gpu/drm/drm_prime.c:438: warning: Function parameter or
> > member 'page_num' not described in 'drm_gem_dmabuf_kmap_atomic'
> > ./drivers/gpu/drm/drm_prime.c:450: warning: Function parameter or
> > member 'dma_buf' not described in 'drm_gem_dmabuf_kunmap_atomic'
> > ./drivers/gpu/drm/drm_prime.c:450: warning: Function parameter or
> > member 'page_num' not described in 'drm_gem_dmabuf_kunmap_atomic'
> > ./drivers/gpu/drm/drm_prime.c:450: warning: Function parameter or
> > member 'addr' not described in 'drm_gem_dmabuf_kunmap_atomic'
> > ./drivers/gpu/drm/drm_prime.c:461: warning: Function parameter or
> > member 'dma_buf' not described in 'drm_gem_dmabuf_kmap'
> > ./drivers/gpu/drm/drm_prime.c:461: warning: Function parameter or
> > member 'page_num' not described in 'drm_gem_dmabuf_kmap'
> > ./drivers/gpu/drm/drm_prime.c:473: warning: Function parameter or
> > member 'dma_buf' not described in 'drm_gem_dmabuf_kunmap'
> > ./drivers/gpu/drm/drm_prime.c:473: warning: Function parameter or
> > member 'page_num' not described in 'drm_gem_dmabuf_kunmap'
> > ./drivers/gpu/drm/drm_prime.c:473: warning: Function parameter or
> > member 'addr' not described in 'drm_gem_dmabuf_kunmap'
> > 
> > Samuel, can you pls build docs using
> > 
> > $ make htmldocs
> > 
> > and fix up the fallout and submit a patch?
> > 
> > Thanks, Daniel
> > 
> > > > -Daniel
> > > >
> > > > >
> > > > > > ---
> > > > > >   drivers/gpu/drm/drm_prime.c | 88
> > > > +++++++++++++++++++++++++++++++++++++++++++++
> > > > > >   1 file changed, 88 insertions(+)
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/drm_prime.c
> > > > > > b/drivers/gpu/drm/drm_prime.c index ca09ce7..e82a976 100644
> > > > > > --- a/drivers/gpu/drm/drm_prime.c
> > > > > > +++ b/drivers/gpu/drm/drm_prime.c
> > > > > > @@ -73,6 +73,9 @@
> > > > > >    * Drivers should detect this situation and return back the gem object
> > > > > >    * from the dma-buf private.  Prime will do this automatically
> > > > > > for drivers
> > > > that
> > > > > >    * use the drm_gem_prime_{import,export} helpers.
> > > > > > + *
> > > > > > + * GEM struct &dma_buf_ops symbols are now exported. They can
> > > > > > + be resued by
> > > > > > + * drivers which implement GEM interface.
> > > > > >    */
> > > > > >   struct drm_prime_member {
> > > > > > @@ -180,6 +183,18 @@ static int
> > > > > > drm_prime_lookup_buf_handle(struct
> > > > drm_prime_file_private *prime_fpri
> > > > > >   	return -ENOENT;
> > > > > >   }
> > > > > > +/**
> > > > > > + * drm_gem_map_attach - dma_buf attach implementation for GEM
> > > > > > + * @dma_buf: buffer to attach device to
> > > > > > + * @target_dev: not used
> > > > > > + * @attach: buffer attachment data
> > > > > > + *
> > > > > > + * Allocates &drm_prime_attachment and calls
> > > > > > +&drm_driver.gem_prime_pin for
> > > > > > + * device specific attachment. This can be used as the
> > > > > > +&dma_buf_ops.attach
> > > > > > + * callback.
> > > > > > + *
> > > > > > + * Returns 0 on success, negative error code on failure.
> > > > > > + */
> > > > > >   int drm_gem_map_attach(struct dma_buf *dma_buf, struct device
> > > > *target_dev,
> > > > > >   		       struct dma_buf_attachment *attach)
> > > > > >   {
> > > > > > @@ -201,6 +216,14 @@ int drm_gem_map_attach(struct dma_buf
> > > > *dma_buf, struct device *target_dev,
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_map_attach);
> > > > > > +/**
> > > > > > + * drm_gem_map_detach - dma_buf detach implementation for
> > GEM
> > > > > > + * @dma_buf: buffer to detach from
> > > > > > + * @attach: attachment to be detached
> > > > > > + *
> > > > > > + * Cleans up &dma_buf_attachment. This can be used as the
> > > > > > +&dma_buf_ops.detach
> > > > > > + * callback.
> > > > > > + */
> > > > > >   void drm_gem_map_detach(struct dma_buf *dma_buf,
> > > > > >   			struct dma_buf_attachment *attach)
> > > > > >   {
> > > > > > @@ -255,6 +278,18 @@ void
> > > > drm_prime_remove_buf_handle_locked(struct drm_prime_file_private
> > > > *prime_fpr
> > > > > >   	}
> > > > > >   }
> > > > > > +/**
> > > > > > + * drm_gem_map_dma_buf - map_dma_buf implementation for
> > GEM
> > > > > > + * @attach: attachment whose scatterlist is to be returned
> > > > > > + * @dir: direction of DMA transfer
> > > > > > + *
> > > > > > + * Calls &drm_driver.gem_prime_get_sg_table and then maps the
> > > > > > +scatterlist. This
> > > > > > + * can be used as the &dma_buf_ops.map_dma_buf callback.
> > > > > > + *
> > > > > > + * Returns sg_table containing the scatterlist to be returned;
> > > > > > +returns ERR_PTR
> > > > > > + * on error. May return -EINTR if it is interrupted by a signal.
> > > > > > + */
> > > > > > +
> > > > > >   struct sg_table *drm_gem_map_dma_buf(struct
> > dma_buf_attachment
> > > > *attach,
> > > > > >   				     enum dma_data_direction dir)
> > > > > >   {
> > > > > > @@ -294,6 +329,12 @@ struct sg_table
> > *drm_gem_map_dma_buf(struct
> > > > dma_buf_attachment *attach,
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_map_dma_buf);
> > > > > > +/**
> > > > > > + * drm_gem_unmap_dma_buf - unmap_dma_buf implementation
> > for
> > > > GEM
> > > > > > + *
> > > > > > + * Not implemented. The unmap is done at
> > drm_gem_map_detach().
> > > > > > +This can be
> > > > > > + * used as the &dma_buf_ops.unmap_dma_buf callback.
> > > > > > + */
> > > > > >   void drm_gem_unmap_dma_buf(struct dma_buf_attachment
> > *attach,
> > > > > >   			   struct sg_table *sgt,
> > > > > >   			   enum dma_data_direction dir) @@ -351,6
> > +392,15
> > > > @@ void
> > > > > > drm_gem_dmabuf_release(struct dma_buf *dma_buf)
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_dmabuf_release);
> > > > > > +/**
> > > > > > + * drm_gem_dmabuf_vmap - dma_buf vmap implementation for
> > GEM
> > > > > > + * @dma_buf: buffer to be mapped
> > > > > > + *
> > > > > > + * Sets up a kernel virtual mapping. This can be used as the
> > > > > > +&dma_buf_ops.vmap
> > > > > > + * callback.
> > > > > > + *
> > > > > > + * Returns the kernel virtual address.
> > > > > > + */
> > > > > >   void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
> > > > > >   {
> > > > > >   	struct drm_gem_object *obj = dma_buf->priv; @@ -360,6
> > +410,14
> > > > @@
> > > > > > void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
> > > > > > +/**
> > > > > > + * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation
> > for
> > > > GEM
> > > > > > + * @dma_buf: buffer to be unmapped
> > > > > > + * @vaddr: the virtual address of the buffer
> > > > > > + *
> > > > > > + * Releases a kernel virtual mapping. This can be used as the
> > > > > > + * &dma_buf_ops.vunmap callback.
> > > > > > + */
> > > > > >   void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void
> > > > *vaddr)
> > > > > >   {
> > > > > >   	struct drm_gem_object *obj = dma_buf->priv; @@ -369,6
> > +427,11
> > > > @@
> > > > > > void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void
> > *vaddr)
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
> > > > > > +/**
> > > > > > + * drm_gem_dmabuf_kmap_atomic - map_atomic implementation
> > for
> > > > GEM
> > > > > > + *
> > > > > > + * Not implemented. This can be used as the
> > > > &dma_buf_ops.map_atomic callback.
> > > > > > + */
> > > > > >   void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
> > > > > >   				 unsigned long page_num)
> > > > > >   {
> > > > > > @@ -376,6 +439,11 @@ void
> > *drm_gem_dmabuf_kmap_atomic(struct
> > > > dma_buf *dma_buf,
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_dmabuf_kmap_atomic);
> > > > > > +/**
> > > > > > + * drm_gem_dmabuf_kunmap_atomic - unmap_atomic
> > > > implementation for
> > > > > > +GEM
> > > > > > + *
> > > > > > + * Not implemented. This can be used as the
> > > > &dma_buf_ops.unmap_atomic callback.
> > > > > > + */
> > > > > >   void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
> > > > > >   				  unsigned long page_num, void
> > *addr)
> > > > > >   {
> > > > > > @@ -383,12 +451,22 @@ void
> > drm_gem_dmabuf_kunmap_atomic(struct
> > > > dma_buf *dma_buf,
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_dmabuf_kunmap_atomic);
> > > > > > +/**
> > > > > > + * drm_gem_dmabuf_kmap - map implementation for GEM
> > > > > > + *
> > > > > > + * Not implemented. This can be used as the &dma_buf_ops.map
> > > > callback.
> > > > > > + */
> > > > > >   void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
> > unsigned
> > > > long page_num)
> > > > > >   {
> > > > > >   	return NULL;
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_dmabuf_kmap);
> > > > > > +/**
> > > > > > + * drm_gem_dmabuf_kunmap - unmap implementation for GEM
> > > > > > + *
> > > > > > + * Not implemented. This can be used as the &dma_buf_ops.unmap
> > > > callback.
> > > > > > + */
> > > > > >   void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
> > unsigned
> > > > long page_num,
> > > > > >   			   void *addr)
> > > > > >   {
> > > > > > @@ -396,6 +474,16 @@ void drm_gem_dmabuf_kunmap(struct
> > > > dma_buf *dma_buf, unsigned long page_num,
> > > > > >   }
> > > > > >   EXPORT_SYMBOL(drm_gem_dmabuf_kunmap);
> > > > > > +/**
> > > > > > + * drm_gem_dmabuf_mmap - dma_buf mmap implementation for
> > > > GEM
> > > > > > + * @dma_buf: buffer to be mapped
> > > > > > + * @vma: virtual address range
> > > > > > + *
> > > > > > + * Provides memory mapping for the buffer. This can be used as
> > > > > > + the
> > > > > > + * &dma_buf_ops.mmap callback.
> > > > > > + *
> > > > > > + * Returns 0 on success or a negative error code on failure.
> > > > > > + */
> > > > > >   int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct
> > > > vm_area_struct *vma)
> > > > > >   {
> > > > > >   	struct drm_gem_object *obj = dma_buf->priv;
> > > > >
> > > > > _______________________________________________
> > > > > dri-devel mailing list
> > > > > dri-devel@lists.freedesktop.org
> > > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > > >
> > > > --
> > > > Daniel Vetter
> > > > Software Engineer, Intel Corporation http://blog.ffwll.ch
> > 
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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