security: min_addr: use max() to improve code

[PATCH] security: min_addr: use max() to improve code

Posted by Qianfeng Rong 1 month, 2 weeks ago

Use max() to reduce the code in update_mmap_min_addr() and improve its
readability.

Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
---
 security/min_addr.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/security/min_addr.c b/security/min_addr.c
index df1bc643d886..50035bc9281c 100644
--- a/security/min_addr.c
+++ b/security/min_addr.c
@@ -16,10 +16,7 @@ unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
 static void update_mmap_min_addr(void)
 {
 #ifdef CONFIG_LSM_MMAP_MIN_ADDR
-	if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
-		mmap_min_addr = dac_mmap_min_addr;
-	else
-		mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
+	mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR);
 #else
 	mmap_min_addr = dac_mmap_min_addr;
 #endif
-- 
2.34.1

Re: [PATCH] security: min_addr: use max() to improve code

Posted by Paul Moore 1 month, 2 weeks ago

On Aug 14, 2025 Qianfeng Rong <rongqianfeng@vivo.com> wrote:
> 
> Use max() to reduce the code in update_mmap_min_addr() and improve its
> readability.
> 
> Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
> ---
>  security/min_addr.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/security/min_addr.c b/security/min_addr.c
> index df1bc643d886..50035bc9281c 100644
> --- a/security/min_addr.c
> +++ b/security/min_addr.c
> @@ -16,10 +16,7 @@ unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
>  static void update_mmap_min_addr(void)
>  {
>  #ifdef CONFIG_LSM_MMAP_MIN_ADDR
> -	if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
> -		mmap_min_addr = dac_mmap_min_addr;
> -	else
> -		mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
> +	mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR);

It seems like the umax() macro would be a better choice here, yes?

It might also be a good idea to explicitly include the
include/linux/minmax.h header in this file.

>  #else
>  	mmap_min_addr = dac_mmap_min_addr;
>  #endif
> -- 
> 2.34.1

--
paul-moore.com

Re: [PATCH] security: min_addr: use max() to improve code

Posted by Qianfeng Rong 1 month, 2 weeks ago

在 2025/8/15 10:17, Paul Moore 写道:
> On Aug 14, 2025 Qianfeng Rong <rongqianfeng@vivo.com> wrote:
>> Use max() to reduce the code in update_mmap_min_addr() and improve its
>> readability.
>>
>> Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
>> ---
>>   security/min_addr.c | 5 +----
>>   1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git a/security/min_addr.c b/security/min_addr.c
>> index df1bc643d886..50035bc9281c 100644
>> --- a/security/min_addr.c
>> +++ b/security/min_addr.c
>> @@ -16,10 +16,7 @@ unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
>>   static void update_mmap_min_addr(void)
>>   {
>>   #ifdef CONFIG_LSM_MMAP_MIN_ADDR
>> -	if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
>> -		mmap_min_addr = dac_mmap_min_addr;
>> -	else
>> -		mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
>> +	mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR);
> It seems like the umax() macro would be a better choice here, yes?


You are right, using umax() here makes the semantics clearer.

>
> It might also be a good idea to explicitly include the
> include/linux/minmax.h header in this file.


ok, Will do in the next version.

>
>>   #else
>>   	mmap_min_addr = dac_mmap_min_addr;
>>   #endif
>> -- 
>> 2.34.1
> --
> paul-moore.com
Best regards,
Qianfeng