usb: musb_dsps: fix the exit routine for debugfs

Message ID 20140423155529.GL9593@saruman.home
State Accepted
Commit 0fca91b8a446d4a38b8f3d4772c4a8665ebcd7b2
Headers show

Commit Message

Felipe Balbi April 23, 2014, 3:55 p.m.
On Wed, Apr 23, 2014 at 05:39:43PM +0200, Olivier Gayot wrote:
> The following commit introduced the debugfs :
> 
> 40f099e32c2a06bad7d75683421e30fcc74924cd
> Author: Markus Pargmann <mpa@pengutronix.de>
> Date:   Fri Jan 17 10:22:35 2014 +0100
> 
>     usb: musb: dsps, debugfs files
> 
> Unfortunately, a forgotten call to a cleanup function prevents the
> probing of musb in case of deferred probe.
> 
> Because musb_init_controller() often retries and creates a new debugfs
> directory each time it is called, we need to remove that directory in case the
> initialization fails. Otherwise, the debugfs_create_dir() fails at
> subsequent calls because the directory already exists.
> 
> Fixed by calling debugfs_remove_recursive() in the exit function.
> 
> Signed-off-by: Olivier Gayot <ogayot@baylibre.com>
> Cc: Markus Pargmann <mpa@pengutronix.de>
> ---
>  drivers/usb/musb/musb_dsps.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
> index 3372ded..c3de0a5 100644
> --- a/drivers/usb/musb/musb_dsps.c
> +++ b/drivers/usb/musb/musb_dsps.c
> @@ -471,6 +471,8 @@ static int dsps_musb_exit(struct musb *musb)
>  
>  	del_timer_sync(&glue->timer);
>  
> +	debugfs_remove_recursive(glue->dbgfs_root);
> +
>  	usb_phy_shutdown(musb->xceiv);
>  	return 0;

First of all this commit is wrong, second of all I already have the
proper commit:

commit 0fca91b8a446d4a38b8f3d4772c4a8665ebcd7b2
Author: Daniel Mack <zonque@gmail.com>
Date:   Wed Apr 2 11:46:51 2014 +0200

    usb: musb: dsps: move debugfs_remove_recursive()
    
    When the platform initialization fails due to missing resources, it will
    return -EPROBE_DEFER after dsps_musb_init() has been called.
    
    dsps_musb_init() calls dsps_musb_dbg_init() to allocate the debugfs
    nodes. At a later point in time, the probe will be retried, and
    dsps_musb_dbg_init() will be called again. debugfs_create_dir() will
    fail this time, as the node already exists, and so the entire device
    probe will fail with -ENOMEM.
    
    Fix this by moving debugfs_remove_recursive() from dsps_remove() to the
    plaform's exit function, so it will be cleanly torn down when the probe
    fails. It also feels more natural this way, as .exit is the counterpart
    to .init.
    
    Signed-off-by: Daniel Mack <zonque@gmail.com>
    Signed-off-by: Felipe Balbi <balbi@ti.com>


a pull request has already been sent to Greg, should be in v3.15-rc3

Comments

Olivier Gayot April 24, 2014, 9:07 a.m. | #1
Ok, thank you, I didn't notice the existing thread.

On Wed, 23 Apr 2014 10:55:29 -0500
Felipe Balbi <balbi@ti.com> wrote:

> On Wed, Apr 23, 2014 at 05:39:43PM +0200, Olivier Gayot wrote:
> > The following commit introduced the debugfs :
> > 
> > 40f099e32c2a06bad7d75683421e30fcc74924cd
> > Author: Markus Pargmann <mpa@pengutronix.de>
> > Date:   Fri Jan 17 10:22:35 2014 +0100
> > 
> >     usb: musb: dsps, debugfs files
> > 
> > Unfortunately, a forgotten call to a cleanup function prevents the
> > probing of musb in case of deferred probe.
> > 
> > Because musb_init_controller() often retries and creates a new
> > debugfs directory each time it is called, we need to remove that
> > directory in case the initialization fails. Otherwise, the
> > debugfs_create_dir() fails at subsequent calls because the
> > directory already exists.
> > 
> > Fixed by calling debugfs_remove_recursive() in the exit function.
> > 
> > Signed-off-by: Olivier Gayot <ogayot@baylibre.com>
> > Cc: Markus Pargmann <mpa@pengutronix.de>
> > ---
> >  drivers/usb/musb/musb_dsps.c |    2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/usb/musb/musb_dsps.c
> > b/drivers/usb/musb/musb_dsps.c index 3372ded..c3de0a5 100644
> > --- a/drivers/usb/musb/musb_dsps.c
> > +++ b/drivers/usb/musb/musb_dsps.c
> > @@ -471,6 +471,8 @@ static int dsps_musb_exit(struct musb *musb)
> >  
> >  	del_timer_sync(&glue->timer);
> >  
> > +	debugfs_remove_recursive(glue->dbgfs_root);
> > +
> >  	usb_phy_shutdown(musb->xceiv);
> >  	return 0;
> 
> First of all this commit is wrong, second of all I already have the
> proper commit:
> 
> commit 0fca91b8a446d4a38b8f3d4772c4a8665ebcd7b2
> Author: Daniel Mack <zonque@gmail.com>
> Date:   Wed Apr 2 11:46:51 2014 +0200
> 
>     usb: musb: dsps: move debugfs_remove_recursive()
>     
>     When the platform initialization fails due to missing resources,
> it will return -EPROBE_DEFER after dsps_musb_init() has been called.
>     
>     dsps_musb_init() calls dsps_musb_dbg_init() to allocate the
> debugfs nodes. At a later point in time, the probe will be retried,
> and dsps_musb_dbg_init() will be called again. debugfs_create_dir()
> will fail this time, as the node already exists, and so the entire
> device probe will fail with -ENOMEM.
>     
>     Fix this by moving debugfs_remove_recursive() from dsps_remove()
> to the plaform's exit function, so it will be cleanly torn down when
> the probe fails. It also feels more natural this way, as .exit is the
> counterpart to .init.
>     
>     Signed-off-by: Daniel Mack <zonque@gmail.com>
>     Signed-off-by: Felipe Balbi <balbi@ti.com>
> 
> diff --git a/drivers/usb/musb/musb_dsps.c
> b/drivers/usb/musb/musb_dsps.c index 3372ded..e2fd263 100644
> --- a/drivers/usb/musb/musb_dsps.c
> +++ b/drivers/usb/musb/musb_dsps.c
> @@ -470,8 +470,9 @@ static int dsps_musb_exit(struct musb *musb)
>  	struct dsps_glue *glue = dev_get_drvdata(dev->parent);
>  
>  	del_timer_sync(&glue->timer);
> -
>  	usb_phy_shutdown(musb->xceiv);
> +	debugfs_remove_recursive(glue->dbgfs_root);
> +
>  	return 0;
>  }
>  
> @@ -708,8 +709,6 @@ static int dsps_remove(struct platform_device
> *pdev) pm_runtime_put(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  
> -	debugfs_remove_recursive(glue->dbgfs_root);
> -
>  	return 0;
>  }
>  
> 
> a pull request has already been sent to Greg, should be in v3.15-rc3
> 

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Felipe Balbi April 24, 2014, 3:10 p.m. | #2
Hi,

On Thu, Apr 24, 2014 at 11:07:34AM +0200, Olivier Gayot wrote:
> Ok, thank you, I didn't notice the existing thread.

no problem, but don't top-post please :-s

Patch

diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
index 3372ded..e2fd263 100644
--- a/drivers/usb/musb/musb_dsps.c
+++ b/drivers/usb/musb/musb_dsps.c
@@ -470,8 +470,9 @@  static int dsps_musb_exit(struct musb *musb)
 	struct dsps_glue *glue = dev_get_drvdata(dev->parent);
 
 	del_timer_sync(&glue->timer);
-
 	usb_phy_shutdown(musb->xceiv);
+	debugfs_remove_recursive(glue->dbgfs_root);
+
 	return 0;
 }
 
@@ -708,8 +709,6 @@  static int dsps_remove(struct platform_device *pdev)
 	pm_runtime_put(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
-	debugfs_remove_recursive(glue->dbgfs_root);
-
 	return 0;
 }