selftests/mm: Drop redundant open() in mprotect_tests()

[PATCH] selftests/mm: Drop redundant open() in mprotect_tests()

Posted by Hongfu Li 1 month, 1 week ago

From: Hongfu Li <lihongfu@kylinos.cn>

Remove duplicate open() for local pagemap_fd in mprotect_tests() that
shadows the global pagemap_fd already opened in main(). The local fd
is never used in the function.

Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
---
 tools/testing/selftests/mm/pagemap_ioctl.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
index cfd1987339c1..eadc7159ca5b 100644
--- a/tools/testing/selftests/mm/pagemap_ioctl.c
+++ b/tools/testing/selftests/mm/pagemap_ioctl.c
@@ -1332,12 +1332,6 @@ int mprotect_tests(void)
 	int ret;
 	char *mem, *mem2;
 	struct page_region vec;
-	int pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
-
-	if (pagemap_fd < 0) {
-		fprintf(stderr, "open() failed\n");
-		exit(1);
-	}
 
 	/* 1. Map two pages */
 	mem = mmap(0, 2 * page_size, PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
-- 
2.54.0

Re: [PATCH] selftests/mm: Drop redundant open() in mprotect_tests()

Posted by David Hildenbrand (Arm) 1 month, 1 week ago

On 8/17/26 10:06, Hongfu Li wrote:
> From: Hongfu Li <lihongfu@kylinos.cn>
> 
> Remove duplicate open() for local pagemap_fd in mprotect_tests() that
> shadows the global pagemap_fd already opened in main(). The local fd
> is never used in the function.
> 
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
> ---

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH] selftests/mm: Drop redundant open() in mprotect_tests()

Posted by Anshuman Khandual 1 month, 1 week ago

On Mon, Aug 17, 2026 at 04:06:16PM +0800, Hongfu Li wrote:
> From: Hongfu Li <lihongfu@kylinos.cn>
> 
> Remove duplicate open() for local pagemap_fd in mprotect_tests() that
> shadows the global pagemap_fd already opened in main(). The local fd
> is never used in the function.
> 
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

> ---
>  tools/testing/selftests/mm/pagemap_ioctl.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
> index cfd1987339c1..eadc7159ca5b 100644
> --- a/tools/testing/selftests/mm/pagemap_ioctl.c
> +++ b/tools/testing/selftests/mm/pagemap_ioctl.c
> @@ -1332,12 +1332,6 @@ int mprotect_tests(void)
>  	int ret;
>  	char *mem, *mem2;
>  	struct page_region vec;
> -	int pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
> -
> -	if (pagemap_fd < 0) {
> -		fprintf(stderr, "open() failed\n");
> -		exit(1);
> -	}
>  
>  	/* 1. Map two pages */
>  	mem = mmap(0, 2 * page_size, PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
> -- 
> 2.54.0
>

Re: [PATCH] selftests/mm: Drop redundant open() in mprotect_tests()

Posted by SJ Park 1 month, 1 week ago

On Mon, 17 Aug 2026 16:06:16 +0800 Hongfu Li <hongfu.li@linux.dev> wrote:

> From: Hongfu Li <lihongfu@kylinos.cn>
> 
> Remove duplicate open() for local pagemap_fd in mprotect_tests() that
> shadows the global pagemap_fd already opened in main(). The local fd
> is never used in the function.

Nice catch!

> 
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>

Reviewed-by: SJ Park <sj@kernel.org>


Thanks,
SJ

[...]

Re: [PATCH] selftests/mm: Drop redundant open() in mprotect_tests()

Posted by Lorenzo Stoakes (ARM) 1 month, 1 week ago

+cc Muhammad

On Mon, Aug 17, 2026 at 04:06:16PM +0800, Hongfu Li wrote:
> From: Hongfu Li <lihongfu@kylinos.cn>
>
> Remove duplicate open() for local pagemap_fd in mprotect_tests() that
> shadows the global pagemap_fd already opened in main(). The local fd
> is never used in the function.
>
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>

Hmm yeah it's not even closed either...

I'm assuming this was an error in the origianl tests, Muhammad - I'm
guessing some artifact of a previous approach or similar?

Anyway, LGTM, so:

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

> ---
>  tools/testing/selftests/mm/pagemap_ioctl.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
> index cfd1987339c1..eadc7159ca5b 100644
> --- a/tools/testing/selftests/mm/pagemap_ioctl.c
> +++ b/tools/testing/selftests/mm/pagemap_ioctl.c
> @@ -1332,12 +1332,6 @@ int mprotect_tests(void)
>  	int ret;
>  	char *mem, *mem2;
>  	struct page_region vec;
> -	int pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
> -
> -	if (pagemap_fd < 0) {
> -		fprintf(stderr, "open() failed\n");
> -		exit(1);
> -	}
>
>  	/* 1. Map two pages */
>  	mem = mmap(0, 2 * page_size, PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
> --
> 2.54.0
>

--
Cheers, Lorenzo

Re: [PATCH] selftests/mm: Drop redundant open() in mprotect_tests()

Posted by Usama Anjum 1 month, 1 week ago

On 17/08/2026 12:29 pm, Lorenzo Stoakes (ARM) wrote:
> +cc Muhammad
> 
> On Mon, Aug 17, 2026 at 04:06:16PM +0800, Hongfu Li wrote:
>> From: Hongfu Li <lihongfu@kylinos.cn>
>>
>> Remove duplicate open() for local pagemap_fd in mprotect_tests() that
>> shadows the global pagemap_fd already opened in main(). The local fd
>> is never used in the function.
>>
>> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
> 
> Hmm yeah it's not even closed either...
> 
> I'm assuming this was an error in the origianl tests, Muhammad - I'm
> guessing some artifact of a previous approach or similar?
Its definitively the dead code.

Reviewed-by: Muhammad Usama Anjum <usama.anjum@arm.com>

> 
> Anyway, LGTM, so:
> 
> Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> 
>> ---
>>  tools/testing/selftests/mm/pagemap_ioctl.c | 6 ------
>>  1 file changed, 6 deletions(-)
>>
>> diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
>> index cfd1987339c1..eadc7159ca5b 100644
>> --- a/tools/testing/selftests/mm/pagemap_ioctl.c
>> +++ b/tools/testing/selftests/mm/pagemap_ioctl.c
>> @@ -1332,12 +1332,6 @@ int mprotect_tests(void)
>>  	int ret;
>>  	char *mem, *mem2;
>>  	struct page_region vec;
>> -	int pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
>> -
>> -	if (pagemap_fd < 0) {
>> -		fprintf(stderr, "open() failed\n");
>> -		exit(1);
>> -	}
>>
>>  	/* 1. Map two pages */
>>  	mem = mmap(0, 2 * page_size, PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
>> --
>> 2.54.0
>>
> 
> --
> Cheers, Lorenzo
>