[dm-devel] [PATCH 2/4] mm/swap: use SECTORS_PER_PAGE_SHIFT to clean up code

[Leizhen (ThunderTown)]

On 2020/5/6 1:25, Matthew Wilcox wrote:
> On Tue, May 05, 2020 at 07:55:41PM +0800, Zhen Lei wrote:
>> +++ b/mm/swapfile.c
>> @@ -177,8 +177,8 @@ static int discard_swap(struct swap_info_struct *si)
>>  
>>  	/* Do not discard the swap header page! */
>>  	se = first_se(si);
>> -	start_block = (se->start_block + 1) << (PAGE_SHIFT - 9);
>> -	nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9);
>> +	start_block = (se->start_block + 1) << SECTORS_PER_PAGE_SHIFT;
>> +	nr_blocks = ((sector_t)se->nr_pages - 1) << SECTORS_PER_PAGE_SHIFT;
> 
> Thinking about this some more, wouldn't this look better?
> 
> 	start_block = page_sectors(se->start_block + 1);
> 	nr_block = page_sectors(se->nr_pages - 1);
> 

OK，That's fine, it's clearer. And in this way, there won't be more than 80 columns.

> 
> .
>