On 09/03/2013 03:01 PM, Wanpeng Li wrote:
> Changelog:
>  *v2 -> v3: revert commit d157a558 directly
> 
> The VM_UNINITIALIZED/VM_UNLIST flag introduced by commit f5252e00(mm: avoid
> null pointer access in vm_struct via /proc/vmallocinfo) is used to avoid
> accessing the pages field with unallocated page when show_numa_info() is
> called. This patch move the check just before show_numa_info in order that
> some messages still can be dumped via /proc/vmallocinfo. This patch revert 
> commit d157a558 (mm/vmalloc.c: check VM_UNINITIALIZED flag in s_show instead 
> of show_numa_info);
> 
> Signed-off-by: Wanpeng Li <liw...@linux.vnet.ibm.com>

Reviewed-by: Zhang Yanfei <zhangyan...@cn.fujitsu.com>

> ---
>  mm/vmalloc.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index e3ec8b4..5368b17 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2562,6 +2562,11 @@ static void show_numa_info(struct seq_file *m, struct 
> vm_struct *v)
>               if (!counters)
>                       return;
>  
> +             /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
> +             smp_rmb();
> +             if (v->flags & VM_UNINITIALIZED)
> +                     return;
> +
>               memset(counters, 0, nr_node_ids * sizeof(unsigned int));
>  
>               for (nr = 0; nr < v->nr_pages; nr++)
> @@ -2590,11 +2595,6 @@ static int s_show(struct seq_file *m, void *p)
>  
>       v = va->vm;
>  
> -     /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
> -     smp_rmb();
> -     if (v->flags & VM_UNINITIALIZED)
> -             return 0;
> -
>       seq_printf(m, "0x%pK-0x%pK %7ld",
>               v->addr, v->addr + v->size, v->size);
>  
> 


-- 
Thanks.
Zhang Yanfei
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