[PATCH] memcg: fix static checker warning

[PATCH] memcg: fix static checker warning

[Kirill A. Shutemov]

The patch "mm: remove rest usage of VM_NONLINEAR and pte_file()" from
Jan 17, 2015, leads to the following static checker warning:

        mm/memcontrol.c:4794 mc_handle_file_pte()
        warn: passing uninitialized 'pgoff'

After the patch, the only case when mc_handle_file_pte() called is
pte_none(ptent). The 'if' check is redundant and lead to the warning.
Let's drop it.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 mm/memcontrol.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index cd42f14d138a..a6140c0764f4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4792,8 +4792,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
 		return NULL;
 
 	mapping = vma->vm_file->f_mapping;
-	if (pte_none(ptent))
-		pgoff = linear_page_index(vma, addr);
+	pgoff = linear_page_index(vma, addr);
 
 	/* page is moved even if it's not RSS of this task(page-faulted). */
 #ifdef CONFIG_SWAP
-- 
2.1.4

Re: [PATCH] memcg: fix static checker warning

[Michal Hocko]

On Mon 26-01-15 14:44:08, Kirill A. Shutemov wrote:
> The patch "mm: remove rest usage of VM_NONLINEAR and pte_file()" from
> Jan 17, 2015, leads to the following static checker warning:
> 
>         mm/memcontrol.c:4794 mc_handle_file_pte()
>         warn: passing uninitialized 'pgoff'
> 
> After the patch, the only case when mc_handle_file_pte() called is
> pte_none(ptent). The 'if' check is redundant and lead to the warning.
> Let's drop it.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

Acked-by: Michal Hocko <mhocko@suse.cz>

> ---
>  mm/memcontrol.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index cd42f14d138a..a6140c0764f4 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4792,8 +4792,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
>  		return NULL;
>  
>  	mapping = vma->vm_file->f_mapping;
> -	if (pte_none(ptent))
> -		pgoff = linear_page_index(vma, addr);
> +	pgoff = linear_page_index(vma, addr);
>  
>  	/* page is moved even if it's not RSS of this task(page-faulted). */
>  #ifdef CONFIG_SWAP
> -- 
> 2.1.4
> 
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-- 
Michal Hocko
SUSE Labs