2020-08-14 23:07:15

by Qi Zheng

Subject: [PATCH] of/fdt: Remove duplicate check in early_init_dt_scan_memory()

When the value of the first reg is not NULL, there will be
two repeated checks. So modify it.

Signed-off-by: Qi Zheng <[email protected]>
---
drivers/of/fdt.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 4602e467ca8b..f54412c00642 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1002,10 +1002,11 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
return 0;

reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
- if (reg == NULL)
+ if (reg == NULL) {
reg = of_get_flat_dt_prop(node, "reg", &l);
- if (reg == NULL)
- return 0;
+ if (reg == NULL)
+ return 0;
+ }

endp = reg + (l / sizeof(__be32));
hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
--
2.25.1

2020-08-17 18:26:42

by Rob Herring

Subject: Re: [PATCH] of/fdt: Remove duplicate check in early_init_dt_scan_memory()

On Fri, Aug 14, 2020 at 4:57 PM Qi Zheng <[email protected]> wrote:
>
> When the value of the first reg is not NULL, there will be
> two repeated checks. So modify it.

I prefer the way it was. I'm sure the compiler is smart enough to
throw out the 2nd check. Plus, 'linux,usable-memory' being present is
the exception, so usually 'reg' will be NULL.

> Signed-off-by: Qi Zheng <[email protected]>
> ---
> drivers/of/fdt.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 4602e467ca8b..f54412c00642 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -1002,10 +1002,11 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
> return 0;
>
> reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
> - if (reg == NULL)
> + if (reg == NULL) {
> reg = of_get_flat_dt_prop(node, "reg", &l);
> - if (reg == NULL)
> - return 0;
> + if (reg == NULL)
> + return 0;
> + }
>
> endp = reg + (l / sizeof(__be32));
> hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
> --
> 2.25.1
>

2020-08-17 23:19:38

by Qi Zheng

Subject: Re: [PATCH] of/fdt: Remove duplicate check in early_init_dt_scan_memory()

On 2020/8/18 上午2:21, Rob Herring wrote:
> On Fri, Aug 14, 2020 at 4:57 PM Qi Zheng <[email protected]> wrote:
>>
>> When the value of the first reg is not NULL, there will be
>> two repeated checks. So modify it.
>
> I prefer the way it was. I'm sure the compiler is smart enough to
> throw out the 2nd check. Plus, 'linux,usable-memory' being present is
> the exception, so usually 'reg' will be NULL.

I got it, and thanks for your review.
Please ignore this patch.

>
>> Signed-off-by: Qi Zheng <[email protected]>
>> ---
>> drivers/of/fdt.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
>> index 4602e467ca8b..f54412c00642 100644
>> --- a/drivers/of/fdt.c
>> +++ b/drivers/of/fdt.c
>> @@ -1002,10 +1002,11 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
>> return 0;
>>
>> reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
>> - if (reg == NULL)
>> + if (reg == NULL) {
>> reg = of_get_flat_dt_prop(node, "reg", &l);
>> - if (reg == NULL)
>> - return 0;
>> + if (reg == NULL)
>> + return 0;
>> + }
>>
>> endp = reg + (l / sizeof(__be32));
>> hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
>> --
>> 2.25.1
>>