[2/4] powerpc/vas: Fix cleanup when VAS is not configured

Message ID 1518234567-24869-2-git-send-email-sukadev@linux.vnet.ibm.com
State Changes Requested
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Series
  • [RESEND,1/4] powerpc/vas: Fix order of cleanup in debugfs dir
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Commit Message

Sukadev Bhattiprolu Feb. 10, 2018, 3:49 a.m.
When VAS is not configured in the system, make sure to remove
the VAS debugfs directory and unregister the platform driver.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/powernv/vas-debug.c | 5 +++++
 arch/powerpc/platforms/powernv/vas.c       | 5 ++++-
 arch/powerpc/platforms/powernv/vas.h       | 1 +
 3 files changed, 10 insertions(+), 1 deletion(-)

Comments

Michael Ellerman Feb. 12, 2018, 5:23 a.m. | #1
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> writes:

> When VAS is not configured in the system, make sure to remove
> the VAS debugfs directory and unregister the platform driver.
>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
...
> diff --git a/arch/powerpc/platforms/powernv/vas.c b/arch/powerpc/platforms/powernv/vas.c
> index aebbe95..f83e27d8 100644
> --- a/arch/powerpc/platforms/powernv/vas.c
> +++ b/arch/powerpc/platforms/powernv/vas.c
> @@ -169,8 +169,11 @@ static int __init vas_init(void)
>  		found++;
>  	}
>  
> -	if (!found)
> +	if (!found) {
> +		platform_driver_unregister(&vas_driver);
> +		vas_cleanup_dbgdir();
>  		return -ENODEV;
> +	}

The better patch would be to move the call to vas_init_dbgdir() down
here, where we know we have successfully registered the driver.

cheers
Sukadev Bhattiprolu Feb. 12, 2018, 8:25 p.m. | #2
Michael Ellerman [mpe@ellerman.id.au] wrote:
> Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> writes:
> 
> > When VAS is not configured in the system, make sure to remove
> > the VAS debugfs directory and unregister the platform driver.
> >
> > Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> ...
> > diff --git a/arch/powerpc/platforms/powernv/vas.c b/arch/powerpc/platforms/powernv/vas.c
> > index aebbe95..f83e27d8 100644
> > --- a/arch/powerpc/platforms/powernv/vas.c
> > +++ b/arch/powerpc/platforms/powernv/vas.c
> > @@ -169,8 +169,11 @@ static int __init vas_init(void)
> >  		found++;
> >  	}
> >  
> > -	if (!found)
> > +	if (!found) {
> > +		platform_driver_unregister(&vas_driver);
> > +		vas_cleanup_dbgdir();
> >  		return -ENODEV;
> > +	}
> 
> The better patch would be to move the call to vas_init_dbgdir() down
> here, where we know we have successfully registered the driver.

Well, when VAS is configured, init_vas_instance() expects the top level
"vas" debugfs dir to already be setup.

We could have each init_vas_instance() assume it is the first and
unconditionally call vas_init_dbgdir(). vas_init_dbgdir() could make
sure to initialize only once.

Or, we could make a separate pass countng "ibm,vas" nodes. If there are
none, skip both steps (dbgdir and registering platform driver).

Sukadev
Michael Ellerman Feb. 13, 2018, 3:17 a.m. | #3
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> writes:

> Michael Ellerman [mpe@ellerman.id.au] wrote:
>> Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> writes:
>> 
>> > When VAS is not configured in the system, make sure to remove
>> > the VAS debugfs directory and unregister the platform driver.
>> >
>> > Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
>> ...
>> > diff --git a/arch/powerpc/platforms/powernv/vas.c b/arch/powerpc/platforms/powernv/vas.c
>> > index aebbe95..f83e27d8 100644
>> > --- a/arch/powerpc/platforms/powernv/vas.c
>> > +++ b/arch/powerpc/platforms/powernv/vas.c
>> > @@ -169,8 +169,11 @@ static int __init vas_init(void)
>> >  		found++;
>> >  	}
>> >  
>> > -	if (!found)
>> > +	if (!found) {
>> > +		platform_driver_unregister(&vas_driver);
>> > +		vas_cleanup_dbgdir();
>> >  		return -ENODEV;
>> > +	}
>> 
>> The better patch would be to move the call to vas_init_dbgdir() down
>> here, where we know we have successfully registered the driver.
>
> Well, when VAS is configured, init_vas_instance() expects the top level
> "vas" debugfs dir to already be setup.

OK.

> We could have each init_vas_instance() assume it is the first and
> unconditionally call vas_init_dbgdir(). vas_init_dbgdir() could make
> sure to initialize only once.

Yeah that looks like a good solution.

cheers

Patch

diff --git a/arch/powerpc/platforms/powernv/vas-debug.c b/arch/powerpc/platforms/powernv/vas-debug.c
index b4de4c6..e6e4067 100644
--- a/arch/powerpc/platforms/powernv/vas-debug.c
+++ b/arch/powerpc/platforms/powernv/vas-debug.c
@@ -207,3 +207,8 @@  void vas_init_dbgdir(void)
 	if (IS_ERR(vas_debugfs))
 		vas_debugfs = NULL;
 }
+
+void vas_cleanup_dbgdir(void)
+{
+	debugfs_remove_recursive(vas_debugfs);
+}
diff --git a/arch/powerpc/platforms/powernv/vas.c b/arch/powerpc/platforms/powernv/vas.c
index aebbe95..f83e27d8 100644
--- a/arch/powerpc/platforms/powernv/vas.c
+++ b/arch/powerpc/platforms/powernv/vas.c
@@ -169,8 +169,11 @@  static int __init vas_init(void)
 		found++;
 	}
 
-	if (!found)
+	if (!found) {
+		platform_driver_unregister(&vas_driver);
+		vas_cleanup_dbgdir();
 		return -ENODEV;
+	}
 
 	pr_devel("Found %d instances\n", found);
 
diff --git a/arch/powerpc/platforms/powernv/vas.h b/arch/powerpc/platforms/powernv/vas.h
index ae0100f..2645613 100644
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -406,6 +406,7 @@  extern struct mutex vas_mutex;
 
 extern struct vas_instance *find_vas_instance(int vasid);
 extern void vas_init_dbgdir(void);
+extern void vas_cleanup_dbgdir(void);
 extern void vas_instance_init_dbgdir(struct vas_instance *vinst);
 extern void vas_window_init_dbgdir(struct vas_window *win);
 extern void vas_window_free_dbgdir(struct vas_window *win);