Re: [PATCH v2 3/3] mm/vmalloc: move VM_UNINITIALIZED just before show_numa_info

[Wanpeng Li <liwanp@linux.vnet.ibm.com>]

On Tue, Sep 03, 2013 at 01:40:46PM +0800, Zhang Yanfei wrote:
>On 09/03/2013 11:00 AM, Wanpeng Li wrote:
>> 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.
>> 
>> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>
>Hmmm, sorry again. Please revert commit
>d157a55815ffff48caec311dfb543ce8a79e283e. That said, we could still
>do the check in show_numa_info like before.
>

Ok.

Regards,
Wanpeng Li 

>> ---
>>  mm/vmalloc.c |   10 +++++-----
>>  1 files changed, 5 insertions(+), 5 deletions(-)
>> 
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index e3ec8b4..c4720cd 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -2590,11 +2590,6 @@ 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);
>>  
>> @@ -2622,6 +2617,11 @@ static int s_show(struct seq_file *m, void *p)
>>  	if (v->flags & VM_VPAGES)
>>  		seq_printf(m, " vpages");
>>  
>> +	/* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
>> +	smp_rmb();
>> +	if (v->flags & VM_UNINITIALIZED)
>> +		return 0;
>> +
>>  	show_numa_info(m, v);
>>  	seq_putc(m, '\n');
>>  	return 0;
>> 
>
>
>-- 
>Thanks.
>Zhang Yanfei

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