Re: [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);