diff mbox series

[11/21] fbcon: Extract fbcon_open/release helpers

Message ID 20220131210552.482606-12-daniel.vetter@ffwll.ch
State Superseded
Headers show
Series some fbcon patches, mostly locking | expand

Commit Message

Daniel Vetter Jan. 31, 2022, 9:05 p.m. UTC
There's two minor behaviour changes in here:
- in error paths we now consistently call fb_ops->fb_release
- fb_release really can't fail (fbmem.c ignores it too) and there's no
  reasonable cleanup we can do anyway.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Claudio Suarez <cssk@net-c.es>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Du Cheng <ducheng2@gmail.com>
---
 drivers/video/fbdev/core/fbcon.c | 107 +++++++++++++++----------------
 1 file changed, 53 insertions(+), 54 deletions(-)

Comments

Sam Ravnborg Feb. 3, 2022, 9:15 p.m. UTC | #1
Hi Daniel,

On Mon, Jan 31, 2022 at 10:05:42PM +0100, Daniel Vetter wrote:
> There's two minor behaviour changes in here:
> - in error paths we now consistently call fb_ops->fb_release
> - fb_release really can't fail (fbmem.c ignores it too) and there's no
>   reasonable cleanup we can do anyway.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Claudio Suarez <cssk@net-c.es>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: Du Cheng <ducheng2@gmail.com>
> ---
>  drivers/video/fbdev/core/fbcon.c | 107 +++++++++++++++----------------
>  1 file changed, 53 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index fa30e1909164..eea2ee14b64c 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -680,19 +680,37 @@ static int fbcon_invalid_charcount(struct fb_info *info, unsigned charcount)
>  
>  #endif /* CONFIG_MISC_TILEBLITTING */
>  
> +static int fbcon_open(struct fb_info *info)
> +{
> +	if (!try_module_get(info->fbops->owner))
> +		return -ENODEV;
> +
> +	if (info->fbops->fb_open &&
> +	    info->fbops->fb_open(info, 0)) {
> +		module_put(info->fbops->owner);
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static void fbcon_release(struct fb_info *info)
> +{
> +	if (info->fbops->fb_release)
> +		info->fbops->fb_release(info, 0);
> +
> +	module_put(info->fbops->owner);
> +}
>  
>  static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
>  				  int unit, int oldidx)
>  {
>  	struct fbcon_ops *ops = NULL;
> -	int err = 0;
> -
> -	if (!try_module_get(info->fbops->owner))
> -		err = -ENODEV;
> +	int err;
>  
> -	if (!err && info->fbops->fb_open &&
> -	    info->fbops->fb_open(info, 0))
> -		err = -ENODEV;
> +	err = fbcon_open(info);
> +	if (err)
> +		return err;
>  
>  	if (!err) {
>  		ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
> @@ -713,7 +731,7 @@ static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
>  
>  	if (err) {
>  		con2fb_map[unit] = oldidx;
> -		module_put(info->fbops->owner);
> +		fbcon_release(info);
>  	}
>  
>  	return err;
> @@ -724,45 +742,34 @@ static int con2fb_release_oldinfo(struct vc_data *vc, struct fb_info *oldinfo,
>  				  int oldidx, int found)
>  {
>  	struct fbcon_ops *ops = oldinfo->fbcon_par;
> -	int err = 0, ret;
> +	int ret;
>  
> -	if (oldinfo->fbops->fb_release &&
> -	    oldinfo->fbops->fb_release(oldinfo, 0)) {
> -		con2fb_map[unit] = oldidx;
The old code assigns con2fb_map[unit] before is calls
newinfo->fbops->fb_release).
I wonder if there can be any callback to fbcon where the value
of con2fb_map[unit] matters?


> -		if (!found && newinfo->fbops->fb_release)
> -			newinfo->fbops->fb_release(newinfo, 0);
> -		if (!found)
> -			module_put(newinfo->fbops->owner);
> -		err = -ENODEV;
> -	}
> +	fbcon_release(oldinfo);
>  
> -	if (!err) {
> -		fbcon_del_cursor_work(oldinfo);
> -		kfree(ops->cursor_state.mask);
> -		kfree(ops->cursor_data);
> -		kfree(ops->cursor_src);
> -		kfree(ops->fontbuffer);
> -		kfree(oldinfo->fbcon_par);
> -		oldinfo->fbcon_par = NULL;
> -		module_put(oldinfo->fbops->owner);
> -		/*
> -		  If oldinfo and newinfo are driving the same hardware,
> -		  the fb_release() method of oldinfo may attempt to
> -		  restore the hardware state.  This will leave the
> -		  newinfo in an undefined state. Thus, a call to
> -		  fb_set_par() may be needed for the newinfo.
> -		*/
> -		if (newinfo && newinfo->fbops->fb_set_par) {
> -			ret = newinfo->fbops->fb_set_par(newinfo);
> +	fbcon_del_cursor_work(oldinfo);


> +	kfree(ops->cursor_state.mask);
> +	kfree(ops->cursor_data);
> +	kfree(ops->cursor_src);
> +	kfree(ops->fontbuffer);
> +	kfree(oldinfo->fbcon_par);
> +	oldinfo->fbcon_par = NULL;
These all look like candidates to stuff into fbcon_release()
That would drop the nice symmetry but make it more consistent.

I think we miss freeing ops->cursor_data in fbcon_exit(),
but I did not follow all the code.

With my ramblings considered the patch is
Acked-by: Sam Ravnborg <sam@ravnborg.org>

	Sam

> +	/*
> +	  If oldinfo and newinfo are driving the same hardware,
> +	  the fb_release() method of oldinfo may attempt to
> +	  restore the hardware state.  This will leave the
> +	  newinfo in an undefined state. Thus, a call to
> +	  fb_set_par() may be needed for the newinfo.
> +	*/
> +	if (newinfo && newinfo->fbops->fb_set_par) {
> +		ret = newinfo->fbops->fb_set_par(newinfo);
>  
> -			if (ret)
> -				printk(KERN_ERR "con2fb_release_oldinfo: "
> -					"detected unhandled fb_set_par error, "
> -					"error code %d\n", ret);
> -		}
> +		if (ret)
> +			printk(KERN_ERR "con2fb_release_oldinfo: "
> +				"detected unhandled fb_set_par error, "
> +				"error code %d\n", ret);
>  	}
>  
> -	return err;
> +	return 0;
>  }
>  
>  static void con2fb_init_display(struct vc_data *vc, struct fb_info *info,
> @@ -917,7 +924,6 @@ static const char *fbcon_startup(void)
>  	struct fbcon_display *p = &fb_display[fg_console];
>  	struct vc_data *vc = vc_cons[fg_console].d;
>  	const struct font_desc *font = NULL;
> -	struct module *owner;
>  	struct fb_info *info = NULL;
>  	struct fbcon_ops *ops;
>  	int rows, cols;
> @@ -936,17 +942,12 @@ static const char *fbcon_startup(void)
>  	if (!info)
>  		return NULL;
>  	
> -	owner = info->fbops->owner;
> -	if (!try_module_get(owner))
> +	if (fbcon_open(info))
>  		return NULL;
> -	if (info->fbops->fb_open && info->fbops->fb_open(info, 0)) {
> -		module_put(owner);
> -		return NULL;
> -	}
>  
>  	ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
>  	if (!ops) {
> -		module_put(owner);
> +		fbcon_release(info);
>  		return NULL;
>  	}
>  
> @@ -3331,10 +3332,6 @@ static void fbcon_exit(void)
>  		}
>  
>  		if (mapped) {
> -			if (info->fbops->fb_release)
> -				info->fbops->fb_release(info, 0);
> -			module_put(info->fbops->owner);
> -
>  			if (info->fbcon_par) {
>  				struct fbcon_ops *ops = info->fbcon_par;
>  
> @@ -3344,6 +3341,8 @@ static void fbcon_exit(void)
>  				kfree(info->fbcon_par);
>  				info->fbcon_par = NULL;
>  			}
> +
> +			fbcon_release(info);
>  		}
>  	}
>  }
> -- 
> 2.33.0
Sam Ravnborg Feb. 3, 2022, 9:32 p.m. UTC | #2
Hi Daniel,

> 
> > +	kfree(ops->cursor_state.mask);
> > +	kfree(ops->cursor_data);
> > +	kfree(ops->cursor_src);
> > +	kfree(ops->fontbuffer);
> > +	kfree(oldinfo->fbcon_par);
> > +	oldinfo->fbcon_par = NULL;
> These all look like candidates to stuff into fbcon_release()
> That would drop the nice symmetry but make it more consistent.
> 
> I think we miss freeing ops->cursor_data in fbcon_exit(),
> but I did not follow all the code.

We agree as I can see this was done in a later patch.

	Sam
Daniel Vetter Feb. 8, 2022, 1:48 p.m. UTC | #3
On Thu, Feb 03, 2022 at 10:15:14PM +0100, Sam Ravnborg wrote:
> Hi Daniel,
> 
> On Mon, Jan 31, 2022 at 10:05:42PM +0100, Daniel Vetter wrote:
> > There's two minor behaviour changes in here:
> > - in error paths we now consistently call fb_ops->fb_release
> > - fb_release really can't fail (fbmem.c ignores it too) and there's no
> >   reasonable cleanup we can do anyway.
> > 
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: Claudio Suarez <cssk@net-c.es>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> > Cc: Du Cheng <ducheng2@gmail.com>
> > ---
> >  drivers/video/fbdev/core/fbcon.c | 107 +++++++++++++++----------------
> >  1 file changed, 53 insertions(+), 54 deletions(-)
> > 
> > diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> > index fa30e1909164..eea2ee14b64c 100644
> > --- a/drivers/video/fbdev/core/fbcon.c
> > +++ b/drivers/video/fbdev/core/fbcon.c
> > @@ -680,19 +680,37 @@ static int fbcon_invalid_charcount(struct fb_info *info, unsigned charcount)
> >  
> >  #endif /* CONFIG_MISC_TILEBLITTING */
> >  
> > +static int fbcon_open(struct fb_info *info)
> > +{
> > +	if (!try_module_get(info->fbops->owner))
> > +		return -ENODEV;
> > +
> > +	if (info->fbops->fb_open &&
> > +	    info->fbops->fb_open(info, 0)) {
> > +		module_put(info->fbops->owner);
> > +		return -ENODEV;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void fbcon_release(struct fb_info *info)
> > +{
> > +	if (info->fbops->fb_release)
> > +		info->fbops->fb_release(info, 0);
> > +
> > +	module_put(info->fbops->owner);
> > +}
> >  
> >  static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
> >  				  int unit, int oldidx)
> >  {
> >  	struct fbcon_ops *ops = NULL;
> > -	int err = 0;
> > -
> > -	if (!try_module_get(info->fbops->owner))
> > -		err = -ENODEV;
> > +	int err;
> >  
> > -	if (!err && info->fbops->fb_open &&
> > -	    info->fbops->fb_open(info, 0))
> > -		err = -ENODEV;
> > +	err = fbcon_open(info);
> > +	if (err)
> > +		return err;
> >  
> >  	if (!err) {
> >  		ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
> > @@ -713,7 +731,7 @@ static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
> >  
> >  	if (err) {
> >  		con2fb_map[unit] = oldidx;
> > -		module_put(info->fbops->owner);
> > +		fbcon_release(info);
> >  	}
> >  
> >  	return err;
> > @@ -724,45 +742,34 @@ static int con2fb_release_oldinfo(struct vc_data *vc, struct fb_info *oldinfo,
> >  				  int oldidx, int found)
> >  {
> >  	struct fbcon_ops *ops = oldinfo->fbcon_par;
> > -	int err = 0, ret;
> > +	int ret;
> >  
> > -	if (oldinfo->fbops->fb_release &&
> > -	    oldinfo->fbops->fb_release(oldinfo, 0)) {
> > -		con2fb_map[unit] = oldidx;
> The old code assigns con2fb_map[unit] before is calls
> newinfo->fbops->fb_release).
> I wonder if there can be any callback to fbcon where the value
> of con2fb_map[unit] matters?

It's all protected by console_lock, so other threads cannot see the
inconsistent state.

Essentially everything in fbcon.c is protected by console_lock().

Do you want me to hammer this in somewhere (maybe in the commit message),
or good enough for your ack?
-Daniel

> 
> 
> > -		if (!found && newinfo->fbops->fb_release)
> > -			newinfo->fbops->fb_release(newinfo, 0);
> > -		if (!found)
> > -			module_put(newinfo->fbops->owner);
> > -		err = -ENODEV;
> > -	}
> > +	fbcon_release(oldinfo);
> >  
> > -	if (!err) {
> > -		fbcon_del_cursor_work(oldinfo);
> > -		kfree(ops->cursor_state.mask);
> > -		kfree(ops->cursor_data);
> > -		kfree(ops->cursor_src);
> > -		kfree(ops->fontbuffer);
> > -		kfree(oldinfo->fbcon_par);
> > -		oldinfo->fbcon_par = NULL;
> > -		module_put(oldinfo->fbops->owner);
> > -		/*
> > -		  If oldinfo and newinfo are driving the same hardware,
> > -		  the fb_release() method of oldinfo may attempt to
> > -		  restore the hardware state.  This will leave the
> > -		  newinfo in an undefined state. Thus, a call to
> > -		  fb_set_par() may be needed for the newinfo.
> > -		*/
> > -		if (newinfo && newinfo->fbops->fb_set_par) {
> > -			ret = newinfo->fbops->fb_set_par(newinfo);
> > +	fbcon_del_cursor_work(oldinfo);
> 
> 
> > +	kfree(ops->cursor_state.mask);
> > +	kfree(ops->cursor_data);
> > +	kfree(ops->cursor_src);
> > +	kfree(ops->fontbuffer);
> > +	kfree(oldinfo->fbcon_par);
> > +	oldinfo->fbcon_par = NULL;
> These all look like candidates to stuff into fbcon_release()
> That would drop the nice symmetry but make it more consistent.
> 
> I think we miss freeing ops->cursor_data in fbcon_exit(),
> but I did not follow all the code.
> 
> With my ramblings considered the patch is
> Acked-by: Sam Ravnborg <sam@ravnborg.org>
> 
> 	Sam
> 
> > +	/*
> > +	  If oldinfo and newinfo are driving the same hardware,
> > +	  the fb_release() method of oldinfo may attempt to
> > +	  restore the hardware state.  This will leave the
> > +	  newinfo in an undefined state. Thus, a call to
> > +	  fb_set_par() may be needed for the newinfo.
> > +	*/
> > +	if (newinfo && newinfo->fbops->fb_set_par) {
> > +		ret = newinfo->fbops->fb_set_par(newinfo);
> >  
> > -			if (ret)
> > -				printk(KERN_ERR "con2fb_release_oldinfo: "
> > -					"detected unhandled fb_set_par error, "
> > -					"error code %d\n", ret);
> > -		}
> > +		if (ret)
> > +			printk(KERN_ERR "con2fb_release_oldinfo: "
> > +				"detected unhandled fb_set_par error, "
> > +				"error code %d\n", ret);
> >  	}
> >  
> > -	return err;
> > +	return 0;
> >  }
> >  
> >  static void con2fb_init_display(struct vc_data *vc, struct fb_info *info,
> > @@ -917,7 +924,6 @@ static const char *fbcon_startup(void)
> >  	struct fbcon_display *p = &fb_display[fg_console];
> >  	struct vc_data *vc = vc_cons[fg_console].d;
> >  	const struct font_desc *font = NULL;
> > -	struct module *owner;
> >  	struct fb_info *info = NULL;
> >  	struct fbcon_ops *ops;
> >  	int rows, cols;
> > @@ -936,17 +942,12 @@ static const char *fbcon_startup(void)
> >  	if (!info)
> >  		return NULL;
> >  	
> > -	owner = info->fbops->owner;
> > -	if (!try_module_get(owner))
> > +	if (fbcon_open(info))
> >  		return NULL;
> > -	if (info->fbops->fb_open && info->fbops->fb_open(info, 0)) {
> > -		module_put(owner);
> > -		return NULL;
> > -	}
> >  
> >  	ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
> >  	if (!ops) {
> > -		module_put(owner);
> > +		fbcon_release(info);
> >  		return NULL;
> >  	}
> >  
> > @@ -3331,10 +3332,6 @@ static void fbcon_exit(void)
> >  		}
> >  
> >  		if (mapped) {
> > -			if (info->fbops->fb_release)
> > -				info->fbops->fb_release(info, 0);
> > -			module_put(info->fbops->owner);
> > -
> >  			if (info->fbcon_par) {
> >  				struct fbcon_ops *ops = info->fbcon_par;
> >  
> > @@ -3344,6 +3341,8 @@ static void fbcon_exit(void)
> >  				kfree(info->fbcon_par);
> >  				info->fbcon_par = NULL;
> >  			}
> > +
> > +			fbcon_release(info);
> >  		}
> >  	}
> >  }
> > -- 
> > 2.33.0
Daniel Vetter Feb. 8, 2022, 7:51 p.m. UTC | #4
On Tue, Feb 08, 2022 at 07:24:03PM +0100, Sam Ravnborg wrote:
> Hi Daniel,
> 
> On Tue, Feb 08, 2022 at 02:48:29PM +0100, Daniel Vetter wrote:
> > On Thu, Feb 03, 2022 at 10:15:14PM +0100, Sam Ravnborg wrote:
> > > Hi Daniel,
> > > 
> > > On Mon, Jan 31, 2022 at 10:05:42PM +0100, Daniel Vetter wrote:
> > > > There's two minor behaviour changes in here:
> > > > - in error paths we now consistently call fb_ops->fb_release
> > > > - fb_release really can't fail (fbmem.c ignores it too) and there's no
> > > >   reasonable cleanup we can do anyway.
> > > > 
> > > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > > > Cc: Daniel Vetter <daniel@ffwll.ch>
> > > > Cc: Claudio Suarez <cssk@net-c.es>
> > > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> > > > Cc: Du Cheng <ducheng2@gmail.com>
> > > > ---
> > > >  drivers/video/fbdev/core/fbcon.c | 107 +++++++++++++++----------------
> > > >  1 file changed, 53 insertions(+), 54 deletions(-)
> > > > 
> > > > diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> > > > index fa30e1909164..eea2ee14b64c 100644
> > > > --- a/drivers/video/fbdev/core/fbcon.c
> > > > +++ b/drivers/video/fbdev/core/fbcon.c
> > > > @@ -680,19 +680,37 @@ static int fbcon_invalid_charcount(struct fb_info *info, unsigned charcount)
> > > >  
> > > >  #endif /* CONFIG_MISC_TILEBLITTING */
> > > >  
> > > > +static int fbcon_open(struct fb_info *info)
> > > > +{
> > > > +	if (!try_module_get(info->fbops->owner))
> > > > +		return -ENODEV;
> > > > +
> > > > +	if (info->fbops->fb_open &&
> > > > +	    info->fbops->fb_open(info, 0)) {
> > > > +		module_put(info->fbops->owner);
> > > > +		return -ENODEV;
> > > > +	}
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static void fbcon_release(struct fb_info *info)
> > > > +{
> > > > +	if (info->fbops->fb_release)
> > > > +		info->fbops->fb_release(info, 0);
> > > > +
> > > > +	module_put(info->fbops->owner);
> > > > +}
> > > >  
> > > >  static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
> > > >  				  int unit, int oldidx)
> > > >  {
> > > >  	struct fbcon_ops *ops = NULL;
> > > > -	int err = 0;
> > > > -
> > > > -	if (!try_module_get(info->fbops->owner))
> > > > -		err = -ENODEV;
> > > > +	int err;
> > > >  
> > > > -	if (!err && info->fbops->fb_open &&
> > > > -	    info->fbops->fb_open(info, 0))
> > > > -		err = -ENODEV;
> > > > +	err = fbcon_open(info);
> > > > +	if (err)
> > > > +		return err;
> > > >  
> > > >  	if (!err) {
> > > >  		ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
> > > > @@ -713,7 +731,7 @@ static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
> > > >  
> > > >  	if (err) {
> > > >  		con2fb_map[unit] = oldidx;
> > > > -		module_put(info->fbops->owner);
> > > > +		fbcon_release(info);
> > > >  	}
> > > >  
> > > >  	return err;
> > > > @@ -724,45 +742,34 @@ static int con2fb_release_oldinfo(struct vc_data *vc, struct fb_info *oldinfo,
> > > >  				  int oldidx, int found)
> > > >  {
> > > >  	struct fbcon_ops *ops = oldinfo->fbcon_par;
> > > > -	int err = 0, ret;
> > > > +	int ret;
> > > >  
> > > > -	if (oldinfo->fbops->fb_release &&
> > > > -	    oldinfo->fbops->fb_release(oldinfo, 0)) {
> > > > -		con2fb_map[unit] = oldidx;
> > > The old code assigns con2fb_map[unit] before is calls
> > > newinfo->fbops->fb_release).
> > > I wonder if there can be any callback to fbcon where the value
> > > of con2fb_map[unit] matters?
> > 
> > It's all protected by console_lock, so other threads cannot see the
> > inconsistent state.
> > 
> > Essentially everything in fbcon.c is protected by console_lock().
> > 
> > Do you want me to hammer this in somewhere (maybe in the commit message),
> > or good enough for your ack?
> 
> No need to spell it out more.

I think this was a very good question, since I had to spend a few minutes
figuring out what exactly and why I've done it too.

So I'll add this explainer, it really should have been in the commit
message!

> Add my a-b and apply it.

Well I need to resend, since there was a minor change due to rebasing on
top of Helge's fbcon scrolling patches instead of mine.

Thanks for your review
-Daniel
> 
> 	Sam
diff mbox series

Patch

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index fa30e1909164..eea2ee14b64c 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -680,19 +680,37 @@  static int fbcon_invalid_charcount(struct fb_info *info, unsigned charcount)
 
 #endif /* CONFIG_MISC_TILEBLITTING */
 
+static int fbcon_open(struct fb_info *info)
+{
+	if (!try_module_get(info->fbops->owner))
+		return -ENODEV;
+
+	if (info->fbops->fb_open &&
+	    info->fbops->fb_open(info, 0)) {
+		module_put(info->fbops->owner);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void fbcon_release(struct fb_info *info)
+{
+	if (info->fbops->fb_release)
+		info->fbops->fb_release(info, 0);
+
+	module_put(info->fbops->owner);
+}
 
 static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
 				  int unit, int oldidx)
 {
 	struct fbcon_ops *ops = NULL;
-	int err = 0;
-
-	if (!try_module_get(info->fbops->owner))
-		err = -ENODEV;
+	int err;
 
-	if (!err && info->fbops->fb_open &&
-	    info->fbops->fb_open(info, 0))
-		err = -ENODEV;
+	err = fbcon_open(info);
+	if (err)
+		return err;
 
 	if (!err) {
 		ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
@@ -713,7 +731,7 @@  static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
 
 	if (err) {
 		con2fb_map[unit] = oldidx;
-		module_put(info->fbops->owner);
+		fbcon_release(info);
 	}
 
 	return err;
@@ -724,45 +742,34 @@  static int con2fb_release_oldinfo(struct vc_data *vc, struct fb_info *oldinfo,
 				  int oldidx, int found)
 {
 	struct fbcon_ops *ops = oldinfo->fbcon_par;
-	int err = 0, ret;
+	int ret;
 
-	if (oldinfo->fbops->fb_release &&
-	    oldinfo->fbops->fb_release(oldinfo, 0)) {
-		con2fb_map[unit] = oldidx;
-		if (!found && newinfo->fbops->fb_release)
-			newinfo->fbops->fb_release(newinfo, 0);
-		if (!found)
-			module_put(newinfo->fbops->owner);
-		err = -ENODEV;
-	}
+	fbcon_release(oldinfo);
 
-	if (!err) {
-		fbcon_del_cursor_work(oldinfo);
-		kfree(ops->cursor_state.mask);
-		kfree(ops->cursor_data);
-		kfree(ops->cursor_src);
-		kfree(ops->fontbuffer);
-		kfree(oldinfo->fbcon_par);
-		oldinfo->fbcon_par = NULL;
-		module_put(oldinfo->fbops->owner);
-		/*
-		  If oldinfo and newinfo are driving the same hardware,
-		  the fb_release() method of oldinfo may attempt to
-		  restore the hardware state.  This will leave the
-		  newinfo in an undefined state. Thus, a call to
-		  fb_set_par() may be needed for the newinfo.
-		*/
-		if (newinfo && newinfo->fbops->fb_set_par) {
-			ret = newinfo->fbops->fb_set_par(newinfo);
+	fbcon_del_cursor_work(oldinfo);
+	kfree(ops->cursor_state.mask);
+	kfree(ops->cursor_data);
+	kfree(ops->cursor_src);
+	kfree(ops->fontbuffer);
+	kfree(oldinfo->fbcon_par);
+	oldinfo->fbcon_par = NULL;
+	/*
+	  If oldinfo and newinfo are driving the same hardware,
+	  the fb_release() method of oldinfo may attempt to
+	  restore the hardware state.  This will leave the
+	  newinfo in an undefined state. Thus, a call to
+	  fb_set_par() may be needed for the newinfo.
+	*/
+	if (newinfo && newinfo->fbops->fb_set_par) {
+		ret = newinfo->fbops->fb_set_par(newinfo);
 
-			if (ret)
-				printk(KERN_ERR "con2fb_release_oldinfo: "
-					"detected unhandled fb_set_par error, "
-					"error code %d\n", ret);
-		}
+		if (ret)
+			printk(KERN_ERR "con2fb_release_oldinfo: "
+				"detected unhandled fb_set_par error, "
+				"error code %d\n", ret);
 	}
 
-	return err;
+	return 0;
 }
 
 static void con2fb_init_display(struct vc_data *vc, struct fb_info *info,
@@ -917,7 +924,6 @@  static const char *fbcon_startup(void)
 	struct fbcon_display *p = &fb_display[fg_console];
 	struct vc_data *vc = vc_cons[fg_console].d;
 	const struct font_desc *font = NULL;
-	struct module *owner;
 	struct fb_info *info = NULL;
 	struct fbcon_ops *ops;
 	int rows, cols;
@@ -936,17 +942,12 @@  static const char *fbcon_startup(void)
 	if (!info)
 		return NULL;
 	
-	owner = info->fbops->owner;
-	if (!try_module_get(owner))
+	if (fbcon_open(info))
 		return NULL;
-	if (info->fbops->fb_open && info->fbops->fb_open(info, 0)) {
-		module_put(owner);
-		return NULL;
-	}
 
 	ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
 	if (!ops) {
-		module_put(owner);
+		fbcon_release(info);
 		return NULL;
 	}
 
@@ -3331,10 +3332,6 @@  static void fbcon_exit(void)
 		}
 
 		if (mapped) {
-			if (info->fbops->fb_release)
-				info->fbops->fb_release(info, 0);
-			module_put(info->fbops->owner);
-
 			if (info->fbcon_par) {
 				struct fbcon_ops *ops = info->fbcon_par;
 
@@ -3344,6 +3341,8 @@  static void fbcon_exit(void)
 				kfree(info->fbcon_par);
 				info->fbcon_par = NULL;
 			}
+
+			fbcon_release(info);
 		}
 	}
 }