Re: [Intel-gfx] [RFC 2/3] drm: Register drmfs filesystem from drm init

2016-12-02 Thread sourab gupta
On Thu, 2016-12-01 at 23:57 -0800, Daniel Vetter wrote:
> On Thu, Dec 01, 2016 at 01:44:16PM +0530, swati.dhin...@intel.com wrote:
> > From: Swati Dhingra 
> > 
> > During drm module initialization, drm_core_init initializes the drmfs
> > filesystem and register this with kernel. A driver specific directory is 
> > created
> > inside drmfs root, and dentry of this directory is saved for subsequent use
> > by the driver (e.g. i915). The driver can then create files/directories 
> > inside
> > this root directory directly.
> > In case of i915 driver, the top directory is created at 
> > '/sys/kernel/drm/i915'.
> > 
> > Signed-off-by: Sourab Gupta 
> > Signed-off-by: Swati Dhingra 
> > ---
> >  drivers/gpu/drm/drm_drv.c | 22 ++
> >  include/drm/drm_drv.h |  3 +++
> >  2 files changed, 25 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > index 84fcfcb..ead360bd 100644
> > --- a/drivers/gpu/drm/drm_drv.c
> > +++ b/drivers/gpu/drm/drm_drv.c
> > @@ -688,6 +688,14 @@ int drm_dev_register(struct drm_device *dev, unsigned 
> > long flags)
> >  {
> > int ret;
> >  
> > +#ifdef CONFIG_DRMFS
> > +   dev->driver->drmfs_root = drmfs_create_dir(dev->driver->name, NULL);
> > +   if (IS_ERR(dev->driver->drmfs_root)) {
> > +   DRM_ERROR("Failed to get drmfs root dentry\n");
> > +   return PTR_ERR(dev->driver->drmfs_root);
> > +   }
> > +#endif
> 
> Don't do #ifdef in the code, instead provide dummy static inline functions
> that do nothing in headers when a feature is disabled. For an example see
> CONFIG_DRM_FBDEV_EMULATION in drm_fb_helper.[hc].
> 
Sorry, Will take take of this going forward.

> Also, drmfs here is seriously lacking documentation. E.g. where are we
> supposed to put different things related to rendering, modesetting, and
> all these issues? You need to add a section in drm-uabi.rst, write
> kernel-doc + overview sections for all of this and pull it in.
> -Daniel
> 
Ok. Will work on adding requisite documentation for drmfs.

Thanks,
Sourab

> > +
> > mutex_lock(_global_mutex);
> >  
> > ret = drm_minor_register(dev, DRM_MINOR_CONTROL);
> > @@ -758,6 +766,9 @@ void drm_dev_unregister(struct drm_device *dev)
> > drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
> > drm_minor_unregister(dev, DRM_MINOR_RENDER);
> > drm_minor_unregister(dev, DRM_MINOR_CONTROL);
> > +#ifdef CONFIG_DRMFS
> > +   drmfs_remove(dev->driver->drmfs_root);
> > +#endif
> >  }
> >  EXPORT_SYMBOL(drm_dev_unregister);
> >  
> > @@ -825,6 +836,9 @@ static void drm_core_exit(void)
> >  {
> > unregister_chrdev(DRM_MAJOR, "drm");
> > debugfs_remove(drm_debugfs_root);
> > +#ifdef CONFIG_DRMFS
> > +   drmfs_fini();
> > +#endif
> > drm_sysfs_destroy();
> > idr_destroy(_minors_idr);
> > drm_connector_ida_destroy();
> > @@ -845,6 +859,14 @@ static int __init drm_core_init(void)
> > goto error;
> > }
> >  
> > +#ifdef CONFIG_DRMFS
> > +   ret = drmfs_init();
> > +   if (ret < 0) {
> > +   DRM_ERROR("Cannot create DRM FS: %d\n", ret);
> > +   goto error;
> > +   }
> > +#endif
> > +
> > drm_debugfs_root = debugfs_create_dir("dri", NULL);
> > if (!drm_debugfs_root) {
> > ret = -ENOMEM;
> > diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> > index aad8bba..34804de 100644
> > --- a/include/drm/drm_drv.h
> > +++ b/include/drm/drm_drv.h
> > @@ -403,6 +403,9 @@ struct drm_driver {
> >  
> > /* List of devices hanging off this driver with stealth attach. */
> > struct list_head legacy_dev_list;
> > +
> > +   /* drmfs parent directory dentry for this driver */
> > +   struct dentry *drmfs_root;
> >  };
> >  
> >  extern __printf(6, 7)
> > -- 
> > 2.7.4
> > 
> > ___
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 


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Re: [Intel-gfx] [RFC 2/3] drm: Register drmfs filesystem from drm init

2016-12-01 Thread Daniel Vetter
On Thu, Dec 01, 2016 at 01:44:16PM +0530, swati.dhin...@intel.com wrote:
> From: Swati Dhingra 
> 
> During drm module initialization, drm_core_init initializes the drmfs
> filesystem and register this with kernel. A driver specific directory is 
> created
> inside drmfs root, and dentry of this directory is saved for subsequent use
> by the driver (e.g. i915). The driver can then create files/directories inside
> this root directory directly.
> In case of i915 driver, the top directory is created at 
> '/sys/kernel/drm/i915'.
> 
> Signed-off-by: Sourab Gupta 
> Signed-off-by: Swati Dhingra 
> ---
>  drivers/gpu/drm/drm_drv.c | 22 ++
>  include/drm/drm_drv.h |  3 +++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 84fcfcb..ead360bd 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -688,6 +688,14 @@ int drm_dev_register(struct drm_device *dev, unsigned 
> long flags)
>  {
>   int ret;
>  
> +#ifdef CONFIG_DRMFS
> + dev->driver->drmfs_root = drmfs_create_dir(dev->driver->name, NULL);
> + if (IS_ERR(dev->driver->drmfs_root)) {
> + DRM_ERROR("Failed to get drmfs root dentry\n");
> + return PTR_ERR(dev->driver->drmfs_root);
> + }
> +#endif

Don't do #ifdef in the code, instead provide dummy static inline functions
that do nothing in headers when a feature is disabled. For an example see
CONFIG_DRM_FBDEV_EMULATION in drm_fb_helper.[hc].

Also, drmfs here is seriously lacking documentation. E.g. where are we
supposed to put different things related to rendering, modesetting, and
all these issues? You need to add a section in drm-uabi.rst, write
kernel-doc + overview sections for all of this and pull it in.
-Daniel

> +
>   mutex_lock(_global_mutex);
>  
>   ret = drm_minor_register(dev, DRM_MINOR_CONTROL);
> @@ -758,6 +766,9 @@ void drm_dev_unregister(struct drm_device *dev)
>   drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
>   drm_minor_unregister(dev, DRM_MINOR_RENDER);
>   drm_minor_unregister(dev, DRM_MINOR_CONTROL);
> +#ifdef CONFIG_DRMFS
> + drmfs_remove(dev->driver->drmfs_root);
> +#endif
>  }
>  EXPORT_SYMBOL(drm_dev_unregister);
>  
> @@ -825,6 +836,9 @@ static void drm_core_exit(void)
>  {
>   unregister_chrdev(DRM_MAJOR, "drm");
>   debugfs_remove(drm_debugfs_root);
> +#ifdef CONFIG_DRMFS
> + drmfs_fini();
> +#endif
>   drm_sysfs_destroy();
>   idr_destroy(_minors_idr);
>   drm_connector_ida_destroy();
> @@ -845,6 +859,14 @@ static int __init drm_core_init(void)
>   goto error;
>   }
>  
> +#ifdef CONFIG_DRMFS
> + ret = drmfs_init();
> + if (ret < 0) {
> + DRM_ERROR("Cannot create DRM FS: %d\n", ret);
> + goto error;
> + }
> +#endif
> +
>   drm_debugfs_root = debugfs_create_dir("dri", NULL);
>   if (!drm_debugfs_root) {
>   ret = -ENOMEM;
> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> index aad8bba..34804de 100644
> --- a/include/drm/drm_drv.h
> +++ b/include/drm/drm_drv.h
> @@ -403,6 +403,9 @@ struct drm_driver {
>  
>   /* List of devices hanging off this driver with stealth attach. */
>   struct list_head legacy_dev_list;
> +
> + /* drmfs parent directory dentry for this driver */
> + struct dentry *drmfs_root;
>  };
>  
>  extern __printf(6, 7)
> -- 
> 2.7.4
> 
> ___
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> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [Intel-gfx] [RFC 2/3] drm: Register drmfs filesystem from drm init

2016-12-01 Thread sourab gupta
On Thu, 2016-12-01 at 00:15 -0800, Chris Wilson wrote:
> On Thu, Dec 01, 2016 at 12:32:32PM +0530, swati.dhin...@intel.com wrote:
> > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > index 84fcfcb..ead360bd 100644
> > --- a/drivers/gpu/drm/drm_drv.c
> > +++ b/drivers/gpu/drm/drm_drv.c
> > @@ -688,6 +688,14 @@ int drm_dev_register(struct drm_device *dev, unsigned 
> > long flags)
> >  {
> > int ret;
> >  
> > +#ifdef CONFIG_DRMFS
> 
> Rule of thumb: avoid #ifdeffry in the body of the code, use headers to
> hide conditional compilation.
Ok. Will do the requisite changes.
> 
> > +   dev->driver->drmfs_root = drmfs_create_dir(dev->driver->name, NULL);
> > +   if (IS_ERR(dev->driver->drmfs_root)) {
> > +   DRM_ERROR("Failed to get drmfs root dentry\n");
> > +   return PTR_ERR(dev->driver->drmfs_root);
> > +   }
> 
> Considering use of drmfs is optional, should an error here prevent the
> driver from loading?
> -Chris

Ok. Will remove the return on the error here.



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Re: [Intel-gfx] [RFC 2/3] drm: Register drmfs filesystem from drm init

2016-12-01 Thread Chris Wilson
On Thu, Dec 01, 2016 at 12:32:32PM +0530, swati.dhin...@intel.com wrote:
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 84fcfcb..ead360bd 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -688,6 +688,14 @@ int drm_dev_register(struct drm_device *dev, unsigned 
> long flags)
>  {
>   int ret;
>  
> +#ifdef CONFIG_DRMFS

Rule of thumb: avoid #ifdeffry in the body of the code, use headers to
hide conditional compilation.

> + dev->driver->drmfs_root = drmfs_create_dir(dev->driver->name, NULL);
> + if (IS_ERR(dev->driver->drmfs_root)) {
> + DRM_ERROR("Failed to get drmfs root dentry\n");
> + return PTR_ERR(dev->driver->drmfs_root);
> + }

Considering use of drmfs is optional, should an error here prevent the
driver from loading?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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