2022-10-21 05:33:51

by Aiqun Yu (Maria)

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

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 <[email protected]>
---
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

2022-10-21 07:53:57

by David Hildenbrand

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

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 <[email protected]>
> ---
> 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

2022-10-21 08:31:27

by Aiqun Yu (Maria)

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

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 <[email protected]>
>> ---
>>   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