| Message ID | 20140618134815.69c4d0a5f916846f9857e9ff@linux-foundation.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jun 18, 2014 at 01:48:15PM -0700, Andrew Morton wrote: > On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote: > > > PPC KVM's CMA area management requires arbitrary bitmap granularity, > > since they want to reserve very large memory and manage this region > > with bitmap that one bit for several pages to reduce management overheads. > > So support arbitrary bitmap granularity for following generalization. > > > > ... > > > > --- a/drivers/base/dma-contiguous.c > > +++ b/drivers/base/dma-contiguous.c > > @@ -38,6 +38,7 @@ struct cma { > > unsigned long base_pfn; > > unsigned long count; > > unsigned long *bitmap; > > + unsigned int order_per_bit; /* Order of pages represented by one bit */ > > struct mutex lock; > > }; > > > > @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit) > > > > static DEFINE_MUTEX(cma_mutex); > > > > +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order) > > +{ > > + return (1 << (align_order >> cma->order_per_bit)) - 1; > > +} > > Might want a "1UL << ..." here. Okay! > > > +static unsigned long cma_bitmap_maxno(struct cma *cma) > > +{ > > + return cma->count >> cma->order_per_bit; > > +} > > + > > +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma, > > + unsigned long pages) > > +{ > > + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit; > > +} > > Ditto. I'm not really sure what the compiler will do in these cases, > but would prefer not to rely on it anyway! Okay! Thanks for fix!
--- a/drivers/base/dma-contiguous.c~dma-cma-support-arbitrary-bitmap-granularity-fix +++ a/drivers/base/dma-contiguous.c @@ -160,7 +160,7 @@ static DEFINE_MUTEX(cma_mutex); static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order) { - return (1 << (align_order >> cma->order_per_bit)) - 1; + return (1UL << (align_order >> cma->order_per_bit)) - 1; } static unsigned long cma_bitmap_maxno(struct cma *cma) @@ -171,7 +171,7 @@ static unsigned long cma_bitmap_maxno(st static unsigned long cma_bitmap_pages_to_bits(struct cma *cma, unsigned long pages) { - return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit; + return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit; } static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)