diff mbox

PCI: keystone: fix incorrect annotations on probe and remove

Message ID 20150108221736.GA39839@dtor-ws
State Accepted
Headers show

Commit Message

Dmitry Torokhov Jan. 8, 2015, 10:17 p.m. UTC 
Even though platform bus is not hot-pluggable, devices on it can be unbound
from the driver and bound back to it via sysfs, so we should not be using
__init annotations on probe() and __exit annotations on remove() methods.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---

Not tested, found by casual code inspection.

 drivers/pci/host/pci-keystone.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Bjorn Helgaas Jan. 23, 2015, 9:34 p.m. UTC | #1 
[+cc Fabio]

On Thu, Jan 08, 2015 at 02:17:36PM -0800, Dmitry Torokhov wrote:
> Even though platform bus is not hot-pluggable, devices on it can be unbound
> from the driver and bound back to it via sysfs, so we should not be using
> __init annotations on probe() and __exit annotations on remove() methods.

I don't completely understand this problem.  Does this mean there should be
no __init/__exit annotations in these drivers at all?  If other PCI host
bridge drivers have the same problem, I'd like to fix them all at once.

For example, after applying this patch, ks_pcie_probe() is non-__init, but
it calls ks_add_pcie_port(), which is still __init.  I thought that was
illegal.

I'm not sure about module_platform_driver_probe() either; it generates
__init and __exit functions.  Should those annotations be removed, too?

> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
> 
> Not tested, found by casual code inspection.
> 
>  drivers/pci/host/pci-keystone.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
> index 1b893bc..7b84e1d 100644
> --- a/drivers/pci/host/pci-keystone.c
> +++ b/drivers/pci/host/pci-keystone.c
> @@ -332,7 +332,7 @@ static const struct of_device_id ks_pcie_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
>  
> -static int __exit ks_pcie_remove(struct platform_device *pdev)
> +static int ks_pcie_remove(struct platform_device *pdev)
>  {
>  	struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
>  
> @@ -341,7 +341,7 @@ static int __exit ks_pcie_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -static int __init ks_pcie_probe(struct platform_device *pdev)
> +static int ks_pcie_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct keystone_pcie *ks_pcie;
> @@ -398,9 +398,9 @@ fail_clk:
>  	return ret;
>  }
>  
> -static struct platform_driver ks_pcie_driver __refdata = {
> +static struct platform_driver ks_pcie_driver = {
>  	.probe  = ks_pcie_probe,
> -	.remove = __exit_p(ks_pcie_remove),
> +	.remove = ks_pcie_remove,
>  	.driver = {
>  		.name	= "keystone-pcie",
>  		.owner	= THIS_MODULE,
> -- 
> 2.2.0.rc0.207.ga3a616c
> 
> 
> -- 
> Dmitry
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Dmitry Torokhov Jan. 23, 2015, 9:47 p.m. UTC | #2 
Hi Bjorn,

On Fri, Jan 23, 2015 at 03:34:12PM -0600, Bjorn Helgaas wrote:
> [+cc Fabio]
> 
> On Thu, Jan 08, 2015 at 02:17:36PM -0800, Dmitry Torokhov wrote:
> > Even though platform bus is not hot-pluggable, devices on it can be unbound
> > from the driver and bound back to it via sysfs, so we should not be using
> > __init annotations on probe() and __exit annotations on remove() methods.
> 
> I don't completely understand this problem.  Does this mean there should be
> no __init/__exit annotations in these drivers at all?  If other PCI host
> bridge drivers have the same problem, I'd like to fix them all at once.

Basically they should not use __init/__exit, unless you take explicit
steps to make sure that devices can't be unbound and bound again later
via sysfs by setting driver->suppress_bind_attrs and/or using
platform_driver_probe(). Note that if you use platform_driver_probe()
then your driver can't cope with -EPROBE_DEFER reported by any of the
subsystems it might be using.

> 
> For example, after applying this patch, ks_pcie_probe() is non-__init, but
> it calls ks_add_pcie_port(), which is still __init.  I thought that was
> illegal.

My bad, I missed that. The __init marking on ks_add_pcie_port() shoudl
be removed as well.

> 
> I'm not sure about module_platform_driver_probe() either; it generates
> __init and __exit functions.  Should those annotations be removed, too?

module_platform_driver_probe() does internally platform_driver_probe()
so it is OK for that probe function be __init (because we'd suppress
sysfs bind/unbind and deferred probing so discaring init section is
safe).

Note that above applied to driver's ->probe() and ->remove() code paths
only.  Marking module init/exit code as __init and __exit is still right
thing to do.

Thanks.

> 
> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > ---
> > 
> > Not tested, found by casual code inspection.
> > 
> >  drivers/pci/host/pci-keystone.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
> > index 1b893bc..7b84e1d 100644
> > --- a/drivers/pci/host/pci-keystone.c
> > +++ b/drivers/pci/host/pci-keystone.c
> > @@ -332,7 +332,7 @@ static const struct of_device_id ks_pcie_of_match[] = {
> >  };
> >  MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
> >  
> > -static int __exit ks_pcie_remove(struct platform_device *pdev)
> > +static int ks_pcie_remove(struct platform_device *pdev)
> >  {
> >  	struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
> >  
> > @@ -341,7 +341,7 @@ static int __exit ks_pcie_remove(struct platform_device *pdev)
> >  	return 0;
> >  }
> >  
> > -static int __init ks_pcie_probe(struct platform_device *pdev)
> > +static int ks_pcie_probe(struct platform_device *pdev)
> >  {
> >  	struct device *dev = &pdev->dev;
> >  	struct keystone_pcie *ks_pcie;
> > @@ -398,9 +398,9 @@ fail_clk:
> >  	return ret;
> >  }
> >  
> > -static struct platform_driver ks_pcie_driver __refdata = {
> > +static struct platform_driver ks_pcie_driver = {
> >  	.probe  = ks_pcie_probe,
> > -	.remove = __exit_p(ks_pcie_remove),
> > +	.remove = ks_pcie_remove,
> >  	.driver = {
> >  		.name	= "keystone-pcie",
> >  		.owner	= THIS_MODULE,
> > -- 
> > 2.2.0.rc0.207.ga3a616c
> > 
> > 
> > -- 
> > Dmitry
Dmitry Torokhov Jan. 23, 2015, 10:03 p.m. UTC | #3 
On Fri, Jan 23, 2015 at 01:47:26PM -0800, Dmitry Torokhov wrote:
> Hi Bjorn,
> 
> On Fri, Jan 23, 2015 at 03:34:12PM -0600, Bjorn Helgaas wrote:
> > [+cc Fabio]
> > 
> > On Thu, Jan 08, 2015 at 02:17:36PM -0800, Dmitry Torokhov wrote:
> > > Even though platform bus is not hot-pluggable, devices on it can be unbound
> > > from the driver and bound back to it via sysfs, so we should not be using
> > > __init annotations on probe() and __exit annotations on remove() methods.
> > 
> > I don't completely understand this problem.  Does this mean there should be
> > no __init/__exit annotations in these drivers at all?  If other PCI host
> > bridge drivers have the same problem, I'd like to fix them all at once.

By the way I think only keystone in drivers/pci has this issue. My
script to find potential issues is:

#!/bin/bash
for i in `grep -rl '__exit\(_p\| \).*remove' $*`; do grep -L platform_driver_probe $i; done

it is not 100% correct and generates both false positives and false
negatives but still fains a few offenders in the tree.

> 
> Basically they should not use __init/__exit, unless you take explicit
> steps to make sure that devices can't be unbound and bound again later
> via sysfs by setting driver->suppress_bind_attrs and/or using
> platform_driver_probe(). Note that if you use platform_driver_probe()
> then your driver can't cope with -EPROBE_DEFER reported by any of the
> subsystems it might be using.
> 
> > 
> > For example, after applying this patch, ks_pcie_probe() is non-__init, but
> > it calls ks_add_pcie_port(), which is still __init.  I thought that was
> > illegal.
> 
> My bad, I missed that. The __init marking on ks_add_pcie_port() shoudl
> be removed as well.
> 
> > 
> > I'm not sure about module_platform_driver_probe() either; it generates
> > __init and __exit functions.  Should those annotations be removed, too?
> 
> module_platform_driver_probe() does internally platform_driver_probe()
> so it is OK for that probe function be __init (because we'd suppress
> sysfs bind/unbind and deferred probing so discaring init section is
> safe).
> 
> Note that above applied to driver's ->probe() and ->remove() code paths
> only.  Marking module init/exit code as __init and __exit is still right
> thing to do.
> 
> Thanks.
> 
> > 
> > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > ---
> > > 
> > > Not tested, found by casual code inspection.
> > > 
> > >  drivers/pci/host/pci-keystone.c | 8 ++++----
> > >  1 file changed, 4 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
> > > index 1b893bc..7b84e1d 100644
> > > --- a/drivers/pci/host/pci-keystone.c
> > > +++ b/drivers/pci/host/pci-keystone.c
> > > @@ -332,7 +332,7 @@ static const struct of_device_id ks_pcie_of_match[] = {
> > >  };
> > >  MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
> > >  
> > > -static int __exit ks_pcie_remove(struct platform_device *pdev)
> > > +static int ks_pcie_remove(struct platform_device *pdev)
> > >  {
> > >  	struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
> > >  
> > > @@ -341,7 +341,7 @@ static int __exit ks_pcie_remove(struct platform_device *pdev)
> > >  	return 0;
> > >  }
> > >  
> > > -static int __init ks_pcie_probe(struct platform_device *pdev)
> > > +static int ks_pcie_probe(struct platform_device *pdev)
> > >  {
> > >  	struct device *dev = &pdev->dev;
> > >  	struct keystone_pcie *ks_pcie;
> > > @@ -398,9 +398,9 @@ fail_clk:
> > >  	return ret;
> > >  }
> > >  
> > > -static struct platform_driver ks_pcie_driver __refdata = {
> > > +static struct platform_driver ks_pcie_driver = {
> > >  	.probe  = ks_pcie_probe,
> > > -	.remove = __exit_p(ks_pcie_remove),
> > > +	.remove = ks_pcie_remove,
> > >  	.driver = {
> > >  		.name	= "keystone-pcie",
> > >  		.owner	= THIS_MODULE,
> > > -- 
> > > 2.2.0.rc0.207.ga3a616c
> > > 
> > > 
> > > -- 
> > > Dmitry
> 
> -- 
> Dmitry
Bjorn Helgaas Jan. 23, 2015, 11:04 p.m. UTC | #4 
On Thu, Jan 08, 2015 at 02:17:36PM -0800, Dmitry Torokhov wrote:
> Even though platform bus is not hot-pluggable, devices on it can be unbound
> from the driver and bound back to it via sysfs, so we should not be using
> __init annotations on probe() and __exit annotations on remove() methods.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

I also removed the __init annotations from ks_pcie_host_init() and
ks_add_pcie_port() and applied this to pci/host-keystone for v3.20, thanks!

> ---
> 
> Not tested, found by casual code inspection.
> 
>  drivers/pci/host/pci-keystone.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
> index 1b893bc..7b84e1d 100644
> --- a/drivers/pci/host/pci-keystone.c
> +++ b/drivers/pci/host/pci-keystone.c
> @@ -332,7 +332,7 @@ static const struct of_device_id ks_pcie_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
>  
> -static int __exit ks_pcie_remove(struct platform_device *pdev)
> +static int ks_pcie_remove(struct platform_device *pdev)
>  {
>  	struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
>  
> @@ -341,7 +341,7 @@ static int __exit ks_pcie_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -static int __init ks_pcie_probe(struct platform_device *pdev)
> +static int ks_pcie_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct keystone_pcie *ks_pcie;
> @@ -398,9 +398,9 @@ fail_clk:
>  	return ret;
>  }
>  
> -static struct platform_driver ks_pcie_driver __refdata = {
> +static struct platform_driver ks_pcie_driver = {
>  	.probe  = ks_pcie_probe,
> -	.remove = __exit_p(ks_pcie_remove),
> +	.remove = ks_pcie_remove,
>  	.driver = {
>  		.name	= "keystone-pcie",
>  		.owner	= THIS_MODULE,
> -- 
> 2.2.0.rc0.207.ga3a616c
> 
> 
> -- 
> Dmitry
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diff mbox

Patch

diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
index 1b893bc..7b84e1d 100644
--- a/drivers/pci/host/pci-keystone.c
+++ b/drivers/pci/host/pci-keystone.c
@@ -332,7 +332,7 @@  static const struct of_device_id ks_pcie_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, ks_pcie_of_match);
 
-static int __exit ks_pcie_remove(struct platform_device *pdev)
+static int ks_pcie_remove(struct platform_device *pdev)
 {
 	struct keystone_pcie *ks_pcie = platform_get_drvdata(pdev);
 
@@ -341,7 +341,7 @@  static int __exit ks_pcie_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static int __init ks_pcie_probe(struct platform_device *pdev)
+static int ks_pcie_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct keystone_pcie *ks_pcie;
@@ -398,9 +398,9 @@  fail_clk:
 	return ret;
 }
 
-static struct platform_driver ks_pcie_driver __refdata = {
+static struct platform_driver ks_pcie_driver = {
 	.probe  = ks_pcie_probe,
-	.remove = __exit_p(ks_pcie_remove),
+	.remove = ks_pcie_remove,
 	.driver = {
 		.name	= "keystone-pcie",
 		.owner	= THIS_MODULE,