of_find_device_by_node() takes a reference to the struct device
when it finds a match via get_device.When returning error we should
call put_device.
Signed-off-by: Peng Hao <[email protected]>
---
arch/arm/mach-omap2/display.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
index f86b72d..c6aa9ed 100644
--- a/arch/arm/mach-omap2/display.c
+++ b/arch/arm/mach-omap2/display.c
@@ -258,6 +258,7 @@ static int __init omapdss_init_of(void)
r = of_platform_populate(node, NULL, NULL, &pdev->dev);
if (r) {
pr_err("Unable to populate DSS submodule devices\n");
+ put_device(&pdev->dev);
return r;
}
--
1.8.3.1
Hi,
Adding devicetree list, Julia, Rob and Tomi to Cc.
* Peng Hao <[email protected]> [190212 23:11]:
> of_find_device_by_node() takes a reference to the struct device
> when it finds a match via get_device.When returning error we should
> call put_device.
>
> Signed-off-by: Peng Hao <[email protected]>
> ---
> arch/arm/mach-omap2/display.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
> index f86b72d..c6aa9ed 100644
> --- a/arch/arm/mach-omap2/display.c
> +++ b/arch/arm/mach-omap2/display.c
> @@ -258,6 +258,7 @@ static int __init omapdss_init_of(void)
> r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> if (r) {
> pr_err("Unable to populate DSS submodule devices\n");
> + put_device(&pdev->dev);
> return r;
> }
In general, if the device tree node is never used afterwards,
should this be just:
r = of_platform_populate(node, NULL, NULL, &pdev->dev);
of_node_put(dev_node);
if (r) {
...
}
If so, Julia might have a Coccinelle recpipe for it?
Regards,
Tony
On Tue, 19 Feb 2019, Tony Lindgren wrote:
> Hi,
>
> Adding devicetree list, Julia, Rob and Tomi to Cc.
>
> * Peng Hao <[email protected]> [190212 23:11]:
> > of_find_device_by_node() takes a reference to the struct device
> > when it finds a match via get_device.When returning error we should
> > call put_device.
> >
> > Signed-off-by: Peng Hao <[email protected]>
> > ---
> > arch/arm/mach-omap2/display.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
> > index f86b72d..c6aa9ed 100644
> > --- a/arch/arm/mach-omap2/display.c
> > +++ b/arch/arm/mach-omap2/display.c
> > @@ -258,6 +258,7 @@ static int __init omapdss_init_of(void)
> > r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> > if (r) {
> > pr_err("Unable to populate DSS submodule devices\n");
> > + put_device(&pdev->dev);
> > return r;
> > }
>
> In general, if the device tree node is never used afterwards,
> should this be just:
>
> r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> of_node_put(dev_node);
Are these solving the same problems? The of_node_put looks clearly
necessary, whether there is a success or failure. I'm not familiar with
put_device. I see that it does a kobject_put, but I don't know what
happens because of that. But it looks like an inconsistency that Peng's
patch only considers the failure case, while your suggestion happens
always.
I guess Peng's patch is motivated by a Coccinelle script that Wen Yang
(also from ZTE) has been working on. Perhaps there is a need to adjust
what is suggested by that script.
[Wen Yang added to CC]
julia
> if (r) {
> ...
> }
>
> If so, Julia might have a Coccinelle recpipe for it?
>
> Regards,
>
> Tony
>
On Tue, 19 Feb 2019, Tony Lindgren wrote:
> Hi,
>
> Adding devicetree list, Julia, Rob and Tomi to Cc.
>
> * Peng Hao <[email protected]> [190212 23:11]:
> > of_find_device_by_node() takes a reference to the struct device
> > when it finds a match via get_device.When returning error we should
> > call put_device.
> >
> > Signed-off-by: Peng Hao <[email protected]>
> > ---
> > arch/arm/mach-omap2/display.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
> > index f86b72d..c6aa9ed 100644
> > --- a/arch/arm/mach-omap2/display.c
> > +++ b/arch/arm/mach-omap2/display.c
> > @@ -258,6 +258,7 @@ static int __init omapdss_init_of(void)
> > r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> > if (r) {
> > pr_err("Unable to populate DSS submodule devices\n");
> > + put_device(&pdev->dev);
> > return r;
> > }
>
> In general, if the device tree node is never used afterwards,
> should this be just:
>
> r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> of_node_put(dev_node);
> if (r) {
> ...
> }
>
> If so, Julia might have a Coccinelle recpipe for it?
Unfortunately this is not really an ideal case for Coccinelle, because
node is the result of calling a local function and Coccinelle doesn't by
default do any interprocedural analysis. It is possible to write a rule
that explicitly looks for one function that returns a device node and then
the pattern of its usage in the caller, though.
julia
* Julia Lawall <[email protected]> [190219 17:33]:
> On Tue, 19 Feb 2019, Tony Lindgren wrote:
> > In general, if the device tree node is never used afterwards,
> > should this be just:
> >
> > r = of_platform_populate(node, NULL, NULL, &pdev->dev);
> > of_node_put(dev_node);
> > if (r) {
> > ...
> > }
> >
> > If so, Julia might have a Coccinelle recpipe for it?
>
> Unfortunately this is not really an ideal case for Coccinelle, because
> node is the result of calling a local function and Coccinelle doesn't by
> default do any interprocedural analysis. It is possible to write a rule
> that explicitly looks for one function that returns a device node and then
> the pattern of its usage in the caller, though.
OK thanks for the information.
Regards,
Tony