diff mbox series

x86/mtrr: Remove redundant code

Message ID 20231018074155.68775-1-jiapeng.chong@linux.alibaba.com
State New
Headers
Series x86/mtrr: Remove redundant code |

Commit Message

Jiapeng Chong Oct. 18, 2023, 7:41 a.m. UTC 
  arch/x86/kernel/cpu/mtrr/cleanup.c:943:4: warning: Value stored to 'highest_pfn' is never read.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=6912
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
 arch/x86/kernel/cpu/mtrr/cleanup.c | 2 --
 1 file changed, 2 deletions(-)

Comments

Ingo Molnar Oct. 18, 2023, 8:41 a.m. UTC | #1 
* Jiapeng Chong <jiapeng.chong@linux.alibaba.com> wrote:

> arch/x86/kernel/cpu/mtrr/cleanup.c:943:4: warning: Value stored to 'highest_pfn' is never read.
> 
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=6912
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> ---
>  arch/x86/kernel/cpu/mtrr/cleanup.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
> index 18cf79d6e2c5..c4ec295cebbc 100644
> --- a/arch/x86/kernel/cpu/mtrr/cleanup.c
> +++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
> @@ -939,8 +939,6 @@ int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
>  	if (mtrr_tom2) {
>  		range[nr_range].start = (1ULL<<(32 - PAGE_SHIFT));
>  		range[nr_range].end = mtrr_tom2 >> PAGE_SHIFT;
> -		if (highest_pfn < range[nr_range].end)
> -			highest_pfn = range[nr_range].end;
>  		nr_range++;
>  	}
>  	nr_range = x86_get_mtrr_mem_range(range, nr_range, 0, 0);

Please explain in the changelog how that redundant code got there and why 
there's no underlying bug to be concerned about.

[ I just did that myself and could share the results - but this kind of 
  analysis has to be done when submitting "cleanup" patches changing such 
  type of code ... or at least it has to be flagged, not just mindlessly 
  removing code ... ]

Thanks,

	Ingo
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
index 18cf79d6e2c5..c4ec295cebbc 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -939,8 +939,6 @@  int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
 	if (mtrr_tom2) {
 		range[nr_range].start = (1ULL<<(32 - PAGE_SHIFT));
 		range[nr_range].end = mtrr_tom2 >> PAGE_SHIFT;
-		if (highest_pfn < range[nr_range].end)
-			highest_pfn = range[nr_range].end;
 		nr_range++;
 	}
 	nr_range = x86_get_mtrr_mem_range(range, nr_range, 0, 0);