[PATCH] drm/tinydrm: Fix drm_driver.fops.owner

[Daniel Vetter]

On Sun, Mar 26, 2017 at 01:56:55AM +0100, Noralf Trønnes wrote:
> 
> Den 25.03.2017 22.32, skrev Daniel Vetter:
> > On Sat, Mar 25, 2017 at 02:56:20PM +0100, Noralf Trønnes wrote:
> > > drm_driver.fops can't be shared since the owner then becomes tinydrm.ko.
> > > Move the fops declaration to the driver.
> > > 
> > > Reported-by: Daniel Vetter <daniel.vetter at intel.com>
> > > Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> > Since it only "breaks" unloading (and only if you force-unload without
> > knowing what you're doing, which is explicitly a developer feature with a
> > big warning) I think perfectly ok to push this in only for 4.12.
> > 
> > > ---
> > >   drivers/gpu/drm/tinydrm/core/tinydrm-core.c | 15 ---------------
> > >   drivers/gpu/drm/tinydrm/mi0283qt.c          | 13 +++++++++++++
> > >   include/drm/tinydrm/tinydrm.h               |  4 +---
> > >   3 files changed, 14 insertions(+), 18 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-core.c b/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
> > > index 6a257dd..fd25c7e5 100644
> > > --- a/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
> > > +++ b/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
> > > @@ -122,21 +122,6 @@ void tinydrm_gem_cma_free_object(struct drm_gem_object *gem_obj)
> > >   }
> > >   EXPORT_SYMBOL_GPL(tinydrm_gem_cma_free_object);
> > > -const struct file_operations tinydrm_fops = {
> > > -	.owner		= THIS_MODULE,
> > > -	.open		= drm_open,
> > > -	.release	= drm_release,
> > > -	.unlocked_ioctl	= drm_ioctl,
> > > -#ifdef CONFIG_COMPAT
> > > -	.compat_ioctl	= drm_compat_ioctl,
> > > -#endif
> > > -	.poll		= drm_poll,
> > > -	.read		= drm_read,
> > > -	.llseek		= no_llseek,
> > > -	.mmap		= drm_gem_cma_mmap,
> > > -};
> > > -EXPORT_SYMBOL(tinydrm_fops);
> > > -
> > >   static struct drm_framebuffer *
> > >   tinydrm_fb_create(struct drm_device *drm, struct drm_file *file_priv,
> > >   		  const struct drm_mode_fb_cmd2 *mode_cmd)
> > > diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c
> > > index b29fe86..fdca37a 100644
> > > --- a/drivers/gpu/drm/tinydrm/mi0283qt.c
> > > +++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
> > > @@ -132,9 +132,22 @@ static const struct drm_display_mode mi0283qt_mode = {
> > >   	TINYDRM_MODE(320, 240, 58, 43),
> > >   };
> > > +static const struct file_operations mi0283qt_fops = {
> > > +	.owner		= THIS_MODULE,
> > > +	.open		= drm_open,
> > > +	.release	= drm_release,
> > > +	.unlocked_ioctl	= drm_ioctl,
> > > +	.compat_ioctl	= drm_compat_ioctl,
> > > +	.poll		= drm_poll,
> > > +	.read		= drm_read,
> > > +	.llseek		= no_llseek,
> > > +	.mmap		= drm_gem_cma_mmap,
> > > +};
> > And then you could use the shiny new DECLARE_DRM_GEM_CMA_FOPS here!
> > 
> > Can you pls respin on top of drm-misc-next?
> 
> Sure, I thought I neeeded to fix this in 4.11 first.

As a rule of thumb, -fixes has the same rules as stable backports. And one
of the guidelines there is that it must be a fix for a real problem, i.e.
something a users could conceivably hit. Entirely theoretic race
condiditions, bugs in module unload code and similar things you'll never
get a bug report for don't qualify.
-Daniel

> 
> Noralf.
> 
> > Thanks, Daniel
> > 
> > > +
> > >   static struct drm_driver mi0283qt_driver = {
> > >   	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
> > >   				  DRIVER_ATOMIC,
> > > +	.fops			= &mi0283qt_fops,
> > >   	TINYDRM_GEM_DRIVER_OPS,
> > >   	.lastclose		= tinydrm_lastclose,
> > >   	.debugfs_init		= mipi_dbi_debugfs_init,
> > > diff --git a/include/drm/tinydrm/tinydrm.h b/include/drm/tinydrm/tinydrm.h
> > > index cf9ca20..00b800d 100644
> > > --- a/include/drm/tinydrm/tinydrm.h
> > > +++ b/include/drm/tinydrm/tinydrm.h
> > > @@ -58,8 +58,7 @@ pipe_to_tinydrm(struct drm_simple_display_pipe *pipe)
> > >   	.gem_prime_mmap		= drm_gem_cma_prime_mmap, \
> > >   	.dumb_create		= drm_gem_cma_dumb_create, \
> > >   	.dumb_map_offset	= drm_gem_cma_dumb_map_offset, \
> > > -	.dumb_destroy		= drm_gem_dumb_destroy, \
> > > -	.fops			= &tinydrm_fops
> > > +	.dumb_destroy		= drm_gem_dumb_destroy
> > >   /**
> > >    * TINYDRM_MODE - tinydrm display mode
> > > @@ -84,7 +83,6 @@ pipe_to_tinydrm(struct drm_simple_display_pipe *pipe)
> > >   	.type = DRM_MODE_TYPE_DRIVER, \
> > >   	.clock = 1 /* pass validation */
> > > -extern const struct file_operations tinydrm_fops;
> > >   void tinydrm_lastclose(struct drm_device *drm);
> > >   void tinydrm_gem_cma_free_object(struct drm_gem_object *gem_obj);
> > >   struct drm_gem_object *
> > > -- 
> > > 2.10.2
> > > 
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel at lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 

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