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(-)
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);
--
2.43.0Hi 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>
Revisiting an old patch (the same applies to 10/10)...
> --- 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;
[...]
> @@ -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);
np is passed to of_genpd_add_provider_onecell(), which stores a copy
for later use, so I think it must not be released in case of success?
I.e. both the old and the new code are wrong?
>
> -out_put:
> - of_node_put(np);
> return error;
> }
> early_initcall(rcar_gen4_sysc_pd_init);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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
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
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
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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
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