diff mbox series

[09/10] pmdomain: renesas: rcar-gen4-sysc: Use scoped device node handling to simplify error paths

Message ID 20240823-cleanup-h-guard-pm-domain-v1-9-8320722eaf39@linaro.org (mailing list archive)
State Changes Requested
Delegated to: Geert Uytterhoeven
Headers show
Series pmdomain: Simplify with cleanup.h | expand

Commit Message

Krzysztof Kozlowski Aug. 23, 2024, 12:51 p.m. UTC
Obtain the device node reference with scoped/cleanup.h to reduce error
handling and make the code a bit simpler.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 drivers/pmdomain/renesas/rcar-gen4-sysc.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

Comments

Geert Uytterhoeven Aug. 27, 2024, 7:48 a.m. UTC | #1
Hi Krzysztof,

On Fri, Aug 23, 2024 at 2:51 PM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
> Obtain the device node reference with scoped/cleanup.h to reduce error
> handling and make the code a bit simpler.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Thanks for your patch!

> --- a/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> +++ b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> @@ -303,12 +304,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>         const struct rcar_gen4_sysc_info *info;
>         const struct of_device_id *match;
>         struct rcar_gen4_pm_domains *domains;
> -       struct device_node *np;
>         void __iomem *base;
>         unsigned int i;
>         int error;
>
> -       np = of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
> +       struct device_node *np __free(device_node) =
> +               of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);

This breaks the declarations/blank-line/code structure, so please move
this up.

If you insist on keeping assignment to and validation of np together,
the line should be split in declaration and assignment.

>         if (!np)
>                 return -ENODEV;
>

> @@ -369,14 +365,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>                 if (error) {
>                         pr_warn("Failed to add PM subdomain %s to parent %u\n",
>                                 area->name, area->parent);
> -                       goto out_put;
> +                       return error;
>                 }
>         }
>
>         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
>
> -out_put:
> -       of_node_put(np);
>         return error;

return of_genpd_add_provider_onecell(...);

>  }
>  early_initcall(rcar_gen4_sysc_pd_init);

Gr{oetje,eeting}s,

                        Geert
Krzysztof Kozlowski Aug. 27, 2024, 9:33 a.m. UTC | #2
On 27/08/2024 09:48, Geert Uytterhoeven wrote:
> Hi Krzysztof,
> 
> On Fri, Aug 23, 2024 at 2:51 PM Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>> Obtain the device node reference with scoped/cleanup.h to reduce error
>> handling and make the code a bit simpler.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> Thanks for your patch!
> 
>> --- a/drivers/pmdomain/renesas/rcar-gen4-sysc.c
>> +++ b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
>> @@ -303,12 +304,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>>         const struct rcar_gen4_sysc_info *info;
>>         const struct of_device_id *match;
>>         struct rcar_gen4_pm_domains *domains;
>> -       struct device_node *np;
>>         void __iomem *base;
>>         unsigned int i;
>>         int error;
>>
>> -       np = of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
>> +       struct device_node *np __free(device_node) =
>> +               of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
> 
> This breaks the declarations/blank-line/code structure, so please move
> this up.

What do you mean "declaration structure"? That's the way how variables
with constructors are expected to be declared - within the code.

> 
> If you insist on keeping assignment to and validation of np together,
> the line should be split in declaration and assignment.

No, that would be inconsistent with cleanup/constructor coding style.
Maybe this is something new, so let me bring previous discussions:

https://lore.kernel.org/all/CAHk-=wicfvWPuRVDG5R1mZSxD8Xg=-0nLOiHay2T_UJ0yDX42g@mail.gmail.com/

https://lore.kernel.org/all/CAHk-=wgRHiV5VSxtfXA4S6aLUmcQYEuB67u3BJPJPtuESs1JyA@mail.gmail.com/

https://lore.kernel.org/all/CAHk-=whvOGL3aNhtps0YksGtzvaob_bvZpbaTcVEqGwNMxB6xg@mail.gmail.com/

and finally it will reach documentation (although it focuses on
unwinding process to be specific - "When the unwind order ..."):
https://lore.kernel.org/all/171175585714.2192972.12661675876300167762.stgit@dwillia2-xfh.jf.intel.com/

> 
>>         if (!np)
>>                 return -ENODEV;
>>
> 
>> @@ -369,14 +365,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>>                 if (error) {
>>                         pr_warn("Failed to add PM subdomain %s to parent %u\n",
>>                                 area->name, area->parent);
>> -                       goto out_put;
>> +                       return error;
>>                 }
>>         }
>>
>>         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
>>
>> -out_put:
>> -       of_node_put(np);
>>         return error;
> 
> return of_genpd_add_provider_onecell(...);

Ack.

Best regards,
Krzysztof
Krzysztof Kozlowski Aug. 27, 2024, 9:39 a.m. UTC | #3
On 27/08/2024 11:33, Krzysztof Kozlowski wrote:
> On 27/08/2024 09:48, Geert Uytterhoeven wrote:
>> Hi Krzysztof,
>>
>> On Fri, Aug 23, 2024 at 2:51 PM Krzysztof Kozlowski
>> <krzysztof.kozlowski@linaro.org> wrote:
>>> Obtain the device node reference with scoped/cleanup.h to reduce error
>>> handling and make the code a bit simpler.
>>>
>>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>
>> Thanks for your patch!
>>
>>> --- a/drivers/pmdomain/renesas/rcar-gen4-sysc.c
>>> +++ b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
>>> @@ -303,12 +304,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>>>         const struct rcar_gen4_sysc_info *info;
>>>         const struct of_device_id *match;
>>>         struct rcar_gen4_pm_domains *domains;
>>> -       struct device_node *np;
>>>         void __iomem *base;
>>>         unsigned int i;
>>>         int error;
>>>
>>> -       np = of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
>>> +       struct device_node *np __free(device_node) =
>>> +               of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
>>
>> This breaks the declarations/blank-line/code structure, so please move
>> this up.
> 
> What do you mean "declaration structure"? That's the way how variables
> with constructors are expected to be declared - within the code.

Continuing thoughts, so you prefer:

	struct rcar_gen4_pm_domains *domains;
	void __iomem *base;
	struct device_node *np __free(device_node) =
		of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);

(assuming I will put it at the end of declarations).

Are you sure this is more readable? It's really long line so it
obfuscates a bit the declarations. The point of the scoped assignment is that
you declare it at point of need/first use.

> 
>>
>> If you insist on keeping assignment to and validation of np together,
>> the line should be split in declaration and assignment.
> 
> No, that would be inconsistent with cleanup/constructor coding style.
> Maybe this is something new, so let me bring previous discussions:
> 
> https://lore.kernel.org/all/CAHk-=wicfvWPuRVDG5R1mZSxD8Xg=-0nLOiHay2T_UJ0yDX42g@mail.gmail.com/
> 
> https://lore.kernel.org/all/CAHk-=wgRHiV5VSxtfXA4S6aLUmcQYEuB67u3BJPJPtuESs1JyA@mail.gmail.com/
> 
> https://lore.kernel.org/all/CAHk-=whvOGL3aNhtps0YksGtzvaob_bvZpbaTcVEqGwNMxB6xg@mail.gmail.com/
> 
> and finally it will reach documentation (although it focuses on
> unwinding process to be specific - "When the unwind order ..."):
> https://lore.kernel.org/all/171175585714.2192972.12661675876300167762.stgit@dwillia2-xfh.jf.intel.com/
> 
>>
>>>         if (!np)
>>>                 return -ENODEV;
>>>
>>
>>> @@ -369,14 +365,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
>>>                 if (error) {
>>>                         pr_warn("Failed to add PM subdomain %s to parent %u\n",
>>>                                 area->name, area->parent);
>>> -                       goto out_put;
>>> +                       return error;
>>>                 }
>>>         }
>>>
>>>         error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
>>>
>>> -out_put:
>>> -       of_node_put(np);
>>>         return error;
>>
>> return of_genpd_add_provider_onecell(...);
> 
> Ack.
> 
> Best regards,
> Krzysztof
> 

Best regards,
Krzysztof
Geert Uytterhoeven Aug. 27, 2024, 10:55 a.m. UTC | #4
Hi Krzysztof,

On Tue, Aug 27, 2024 at 11:39 AM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
> On 27/08/2024 11:33, Krzysztof Kozlowski wrote:
> > On 27/08/2024 09:48, Geert Uytterhoeven wrote:
> >> On Fri, Aug 23, 2024 at 2:51 PM Krzysztof Kozlowski
> >> <krzysztof.kozlowski@linaro.org> wrote:
> >>> Obtain the device node reference with scoped/cleanup.h to reduce error
> >>> handling and make the code a bit simpler.
> >>>
> >>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> >>
> >> Thanks for your patch!
> >>
> >>> --- a/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> >>> +++ b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
> >>> @@ -303,12 +304,12 @@ static int __init rcar_gen4_sysc_pd_init(void)
> >>>         const struct rcar_gen4_sysc_info *info;
> >>>         const struct of_device_id *match;
> >>>         struct rcar_gen4_pm_domains *domains;
> >>> -       struct device_node *np;
> >>>         void __iomem *base;
> >>>         unsigned int i;
> >>>         int error;
> >>>
> >>> -       np = of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
> >>> +       struct device_node *np __free(device_node) =
> >>> +               of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
> >>
> >> This breaks the declarations/blank-line/code structure, so please move
> >> this up.
> >
> > What do you mean "declaration structure"? That's the way how variables

First a block with declarations, then a blank line, followed by the actual code
(yeah, the pre-C99 style ;-)

> > with constructors are expected to be declared - within the code.

When it matters.

> Continuing thoughts, so you prefer:
>
>         struct rcar_gen4_pm_domains *domains;
>         void __iomem *base;
>         struct device_node *np __free(device_node) =
>                 of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
>
> (assuming I will put it at the end of declarations).
>
> Are you sure this is more readable? It's really long line so it
> obfuscates a bit the declarations. The point of the scoped assignment is that
> you declare it at point of need/first use.

You're missing reverse Christmas tree order...

> >> If you insist on keeping assignment to and validation of np together,
> >> the line should be split in declaration and assignment.
> >
> > No, that would be inconsistent with cleanup/constructor coding style.
> > Maybe this is something new, so let me bring previous discussions:

[...]

> > and finally it will reach documentation (although it focuses on

Oh, "finally" as in not yet upstream ;-)

> > unwinding process to be specific - "When the unwind order ..."):
> > https://lore.kernel.org/all/171175585714.2192972.12661675876300167762.stgit@dwillia2-xfh.jf.intel.com/

"When the unwind order matters..."

So it's perfectly fine to have:

    static int __init rcar_gen4_sysc_pd_init(void)
    {
            struct device_node *np __free(device_node) = NULL;
            struct rcar_gen4_pm_domains *domains;
            const struct rcar_gen4_sysc_info *info;
            const struct of_device_id *match;
            void __iomem *base;
            unsigned int i;
            int error;

            np = of_find_matching_node_and_match(NULL,
rcar_gen4_sysc_matches, &match);
            if (!np)
                    return -ENODEV;

            ...
    }

But my first suggestion:

    static int __init rcar_gen4_sysc_pd_init(void)
    {
            struct device_node *np __free(device_node) =
                    of_find_matching_node_and_match(NULL,
rcar_gen4_sysc_matches, &match);
            struct rcar_gen4_pm_domains *domains;
            const struct rcar_gen4_sysc_info *info;
            const struct of_device_id *match;
            void __iomem *base;
            unsigned int i;
            int error;

            if (!np)
                    return -ENODEV;

            ...
    }

is safer w.r.t. to future modification.

Gr{oetje,eeting}s,

                        Geert
Krzysztof Kozlowski Aug. 27, 2024, 11:12 a.m. UTC | #5
On 27/08/2024 12:55, Geert Uytterhoeven wrote:
> 
> So it's perfectly fine to have:
> 
>     static int __init rcar_gen4_sysc_pd_init(void)
>     {
>             struct device_node *np __free(device_node) = NULL;
>             struct rcar_gen4_pm_domains *domains;
>             const struct rcar_gen4_sysc_info *info;
>             const struct of_device_id *match;
>             void __iomem *base;
>             unsigned int i;
>             int error;
> 
>             np = of_find_matching_node_and_match(NULL,
> rcar_gen4_sysc_matches, &match);
>             if (!np)
>                     return -ENODEV;
> 
>             ...
>     }

It is not perfectly fine because it does not match the preference of
having declaration with the constructor. See responses from Linus.

> 
> But my first suggestion:
> 
>     static int __init rcar_gen4_sysc_pd_init(void)
>     {
>             struct device_node *np __free(device_node) =
>                     of_find_matching_node_and_match(NULL,
> rcar_gen4_sysc_matches, &match);
>             struct rcar_gen4_pm_domains *domains;
>             const struct rcar_gen4_sysc_info *info;
>             const struct of_device_id *match;
>             void __iomem *base;
>             unsigned int i;
>             int error;
> 
>             if (!np)
>                     return -ENODEV;
> 
>             ...
>     }
> 
> is safer w.r.t. to future modification.

Indeed, sure, I will re-write it above.



Best regards,
Krzysztof
diff mbox series

Patch

diff --git a/drivers/pmdomain/renesas/rcar-gen4-sysc.c b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
index 66409cff2083..4ca85dbdedc2 100644
--- a/drivers/pmdomain/renesas/rcar-gen4-sysc.c
+++ b/drivers/pmdomain/renesas/rcar-gen4-sysc.c
@@ -6,6 +6,7 @@ 
  */
 
 #include <linux/bits.h>
+#include <linux/cleanup.h>
 #include <linux/clk/renesas.h>
 #include <linux/delay.h>
 #include <linux/err.h>
@@ -303,12 +304,12 @@  static int __init rcar_gen4_sysc_pd_init(void)
 	const struct rcar_gen4_sysc_info *info;
 	const struct of_device_id *match;
 	struct rcar_gen4_pm_domains *domains;
-	struct device_node *np;
 	void __iomem *base;
 	unsigned int i;
 	int error;
 
-	np = of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
+	struct device_node *np __free(device_node) =
+		of_find_matching_node_and_match(NULL, rcar_gen4_sysc_matches, &match);
 	if (!np)
 		return -ENODEV;
 
@@ -317,17 +318,14 @@  static int __init rcar_gen4_sysc_pd_init(void)
 	base = of_iomap(np, 0);
 	if (!base) {
 		pr_warn("%pOF: Cannot map regs\n", np);
-		error = -ENOMEM;
-		goto out_put;
+		return -ENOMEM;
 	}
 
 	rcar_gen4_sysc_base = base;
 
 	domains = kzalloc(sizeof(*domains), GFP_KERNEL);
-	if (!domains) {
-		error = -ENOMEM;
-		goto out_put;
-	}
+	if (!domains)
+		return -ENOMEM;
 
 	domains->onecell_data.domains = domains->domains;
 	domains->onecell_data.num_domains = ARRAY_SIZE(domains->domains);
@@ -345,10 +343,8 @@  static int __init rcar_gen4_sysc_pd_init(void)
 
 		n = strlen(area->name) + 1;
 		pd = kzalloc(sizeof(*pd) + n, GFP_KERNEL);
-		if (!pd) {
-			error = -ENOMEM;
-			goto out_put;
-		}
+		if (!pd)
+			return -ENOMEM;
 
 		memcpy(pd->name, area->name, n);
 		pd->genpd.name = pd->name;
@@ -357,7 +353,7 @@  static int __init rcar_gen4_sysc_pd_init(void)
 
 		error = rcar_gen4_sysc_pd_setup(pd);
 		if (error)
-			goto out_put;
+			return error;
 
 		domains->domains[area->pdr] = &pd->genpd;
 
@@ -369,14 +365,12 @@  static int __init rcar_gen4_sysc_pd_init(void)
 		if (error) {
 			pr_warn("Failed to add PM subdomain %s to parent %u\n",
 				area->name, area->parent);
-			goto out_put;
+			return error;
 		}
 	}
 
 	error = of_genpd_add_provider_onecell(np, &domains->onecell_data);
 
-out_put:
-	of_node_put(np);
 	return error;
 }
 early_initcall(rcar_gen4_sysc_pd_init);