2023-10-18 07:42:21

by Jiapeng Chong

Subject: [PATCH] x86/mtrr: Remove redundant code

arch/x86/kernel/cpu/mtrr/cleanup.c:943:4: warning: Value stored to 'highest_pfn' is never read.

Reported-by: Abaci Robot <[email protected]>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=6912
Signed-off-by: Jiapeng Chong <[email protected]>
---
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);
--
2.20.1.7.g153144c

2023-10-18 08:41:56

by Ingo Molnar

Subject: Re: [PATCH] x86/mtrr: Remove redundant code

* Jiapeng Chong <[email protected]> wrote:

> arch/x86/kernel/cpu/mtrr/cleanup.c:943:4: warning: Value stored to 'highest_pfn' is never read.
>
> Reported-by: Abaci Robot <[email protected]>
> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=6912
> Signed-off-by: Jiapeng Chong <[email protected]>
> ---
> 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