[PATCH v1 1/1] kexec: Remove unused code in kimage_load_cma_segment()

[PATCH v1 1/1] kexec: Remove unused code in kimage_load_cma_segment()

[Andy Shevchenko]

clang is not happy about set but unused variable:

kernel/kexec_core.c:745:16: error: variable 'maddr' set but not used [-Werror,-Wunused-but-set-variable]
  745 |         unsigned long maddr;
      |                       ^
1 error generated.

Fix the compilation breakage (`make W=1` build) by removing unused variable.

Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 kernel/kexec_core.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 5357ed39e9d1..32722926bc7e 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -742,7 +742,6 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
 	struct kexec_segment *segment = &image->segment[idx];
 	struct page *cma = image->segment_cma[idx];
 	char *ptr = page_address(cma);
-	unsigned long maddr;
 	size_t ubytes, mbytes;
 	int result = 0;
 	unsigned char __user *buf = NULL;
@@ -754,7 +753,6 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
 		buf = segment->buf;
 	ubytes = segment->bufsz;
 	mbytes = segment->memsz;
-	maddr = segment->mem;
 
 	/* Then copy from source buffer to the CMA one */
 	while (mbytes) {
@@ -782,7 +780,6 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
 		}
 
 		ptr    += mchunk;
-		maddr  += mchunk;
 		mbytes -= mchunk;
 
 		cond_resched();
-- 
2.50.1

Re: [PATCH v1 1/1] kexec: Remove unused code in kimage_load_cma_segment()

[Nathan Chancellor]

Hi Andy,

On Mon, Sep 15, 2025 at 05:55:43PM +0200, Andy Shevchenko wrote:
> clang is not happy about set but unused variable:
> 
> kernel/kexec_core.c:745:16: error: variable 'maddr' set but not used [-Werror,-Wunused-but-set-variable]
>   745 |         unsigned long maddr;
>       |                       ^
> 1 error generated.
> 
> Fix the compilation breakage (`make W=1` build) by removing unused variable.
> 
> Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")

I don't think this fixes tag is right. maddr definitely looks used in
that diff. I think it is a follow up simplification that introduces
this.

Fixes: f4fecb50d6e1 ("kexec_core: remove superfluous page offset handling in segment loading")

> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---

Otherwise, this patch looks correct to me and GCC 16 will warn on this
as well.

  kernel/kexec_core.c: In function 'kimage_load_cma_segment':
  kernel/kexec_core.c:745:23: error: variable 'maddr' set but not used [-Werror=unused-but-set-variable=]
    745 |         unsigned long maddr;
        |                       ^~~~~

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

>  kernel/kexec_core.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index 5357ed39e9d1..32722926bc7e 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -742,7 +742,6 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
>  	struct kexec_segment *segment = &image->segment[idx];
>  	struct page *cma = image->segment_cma[idx];
>  	char *ptr = page_address(cma);
> -	unsigned long maddr;
>  	size_t ubytes, mbytes;
>  	int result = 0;
>  	unsigned char __user *buf = NULL;
> @@ -754,7 +753,6 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
>  		buf = segment->buf;
>  	ubytes = segment->bufsz;
>  	mbytes = segment->memsz;
> -	maddr = segment->mem;
>  
>  	/* Then copy from source buffer to the CMA one */
>  	while (mbytes) {
> @@ -782,7 +780,6 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
>  		}
>  
>  		ptr    += mchunk;
> -		maddr  += mchunk;
>  		mbytes -= mchunk;
>  
>  		cond_resched();
> -- 
> 2.50.1
> 

Re: [PATCH v1 1/1] kexec: Remove unused code in kimage_load_cma_segment()

[Andy Shevchenko]

On Mon, Sep 15, 2025 at 03:14:36PM -0700, Nathan Chancellor wrote:
> Hi Andy,
> 
> On Mon, Sep 15, 2025 at 05:55:43PM +0200, Andy Shevchenko wrote:
> > clang is not happy about set but unused variable:
> > 
> > kernel/kexec_core.c:745:16: error: variable 'maddr' set but not used [-Werror,-Wunused-but-set-variable]
> >   745 |         unsigned long maddr;
> >       |                       ^
> > 1 error generated.
> > 
> > Fix the compilation breakage (`make W=1` build) by removing unused variable.
> > 
> > Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
> 
> I don't think this fixes tag is right. maddr definitely looks used in
> that diff. I think it is a follow up simplification that introduces
> this.
> 
> Fixes: f4fecb50d6e1 ("kexec_core: remove superfluous page offset handling in segment loading")

Oh, you are right!

> Otherwise, this patch looks correct to me and GCC 16 will warn on this
> as well.
> 
>   kernel/kexec_core.c: In function 'kimage_load_cma_segment':
>   kernel/kexec_core.c:745:23: error: variable 'maddr' set but not used [-Werror=unused-but-set-variable=]
>     745 |         unsigned long maddr;
>         |                       ^~~~~

I'll add this as well to the commit message (in shorter form).

> Reviewed-by: Nathan Chancellor <nathan@kernel.org>

Thank you! I'm going to send a v2 soon.

-- 
With Best Regards,
Andy Shevchenko