[PATCH V5 01/17] powerpc/mm/slice: Convert slice_mask high slice to a bitmap

[Aneesh Kumar K.V]

On Wednesday 29 March 2017 08:41 AM, Paul Mackerras wrote:
> On Wed, Mar 22, 2017 at 09:06:47AM +0530, Aneesh Kumar K.V wrote:
>> In followup patch we want to increase the va range which will result
>> in us requiring high_slices to have more than 64 bits. To enable this
>> convert high_slices to bitmap. We keep the number bits same in this patch
>> and later change that to higher value
>
> See comment below...
>
>> @@ -531,8 +569,8 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
>>  	slice_print_mask(" mask", mask);
>>
>>   convert:
>> -	andnot_mask(mask, good_mask);
>> -	andnot_mask(mask, compat_mask);
>> +	slice_andnot_mask(&mask, &good_mask);
>> +	slice_andnot_mask(&mask, &compat_mask);
>>  	if (mask.low_slices || mask.high_slices) {
>
> The test on mask.high_slices here wants to test whether high_slices
> has any bits set, but with the conversion to a bitmap, the test will
> be always true since what will be tested is the address of the array
> in the bitmap.
>

Thanks for the review. How about the below change ?


diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index f808f99372e4..252d90b7c3c5 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -588,7 +588,7 @@ unsigned long slice_get_unmapped_area(unsigned long 
addr, unsigned long len,
   convert:
         slice_andnot_mask(&mask, &good_mask);
         slice_andnot_mask(&mask, &compat_mask);
-       if (mask.low_slices || mask.high_slices) {
+       if (mask.low_slices || !bitmap_empty(mask.high_slices, 
SLICE_NUM_HIGH)) {
                 slice_convert(mm, mask, psize);
                 if (psize > MMU_PAGE_BASE)
                         on_each_cpu(slice_flush_segments, mm, 1);