[PATCH v2 0/1] mm/page_isolation: fix clang deadcode warning

[PATCH v2 0/1] mm/page_isolation: fix clang deadcode warning

[Maria Yu]

When !CONFIG_VM_BUG_ON, there is warning of
clang-analyzer-deadcode.DeadStores:
Value stored to 'mt' during its initialization
is never read.

Difference with previous patch is just to make it
new lines as it is too long for single line.

Feel free to give comments and suggestions. Thanks.

previous discussion here:
[1] https://lore.kernel.org/linux-mm/20221021030953.34925-1-quic_aiquny@quicinc.com/

Maria Yu (1):
  mm/page_isolation: fix clang deadcode warning

 mm/page_isolation.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

-- 
2.17.1

[PATCH v2 1/1] mm/page_isolation: fix clang deadcode warning

[Maria Yu]

When !CONFIG_VM_BUG_ON, there is warning of
clang-analyzer-deadcode.DeadStores:
Value stored to 'mt' during its initialization
is never read.

Signed-off-by: Maria Yu <quic_aiquny@quicinc.com>
---
 mm/page_isolation.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 04141a9bea70..a7a478a22123 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -330,9 +330,8 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
 				      zone->zone_start_pfn);
 
 	if (skip_isolation) {
-		int mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
-
-		VM_BUG_ON(!is_migrate_isolate(mt));
+		VM_BUG_ON(!is_migrate_isolate(get_pageblock_migratetype(
+						pfn_to_page(isolate_pageblock))));
 	} else {
 		ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock), migratetype,
 				flags, isolate_pageblock, isolate_pageblock + pageblock_nr_pages);
-- 
2.17.1

Re: [PATCH v2 1/1] mm/page_isolation: fix clang deadcode warning

[David Hildenbrand]

On 21.10.22 07:19, Maria Yu wrote:
> When !CONFIG_VM_BUG_ON, there is warning of
> clang-analyzer-deadcode.DeadStores:
> Value stored to 'mt' during its initialization
> is never read.
> 
> Signed-off-by: Maria Yu <quic_aiquny@quicinc.com>
> ---
>   mm/page_isolation.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 04141a9bea70..a7a478a22123 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -330,9 +330,8 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
>   				      zone->zone_start_pfn);
>   
>   	if (skip_isolation) {
> -		int mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));

__maybe_unused should work as well. Was that considered?

-- 
Thanks,

David / dhildenb

Re: [PATCH v2 1/1] mm/page_isolation: fix clang deadcode warning

[Aiqun(Maria) Yu]

On 10/21/2022 2:54 PM, David Hildenbrand wrote:
> On 21.10.22 07:19, Maria Yu wrote:
>> When !CONFIG_VM_BUG_ON, there is warning of
>> clang-analyzer-deadcode.DeadStores:
>> Value stored to 'mt' during its initialization
>> is never read.
>>
>> Signed-off-by: Maria Yu <quic_aiquny@quicinc.com>
>> ---
>>   mm/page_isolation.c | 5 ++---
>>   1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
>> index 04141a9bea70..a7a478a22123 100644
>> --- a/mm/page_isolation.c
>> +++ b/mm/page_isolation.c
>> @@ -330,9 +330,8 @@ static int isolate_single_pageblock(unsigned long 
>> boundary_pfn, int flags,
>>                         zone->zone_start_pfn);
>>       if (skip_isolation) {
>> -        int mt = 
>> get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
> 
> __maybe_unused should work as well. Was that considered?
> 
good idea.

-- 
Thx and BRs,
Aiqun(Maria) Yu