On Tue, Feb 24 2015, Danesh Petigara <[email protected]> wrote: > The CMA aligned offset calculation is incorrect for > non-zero order_per_bit values. > > For example, if cma->order_per_bit=1, cma->base_pfn= > 0x2f800000 and align_order=12, the function returns > a value of 0x17c00 instead of 0x400. > > This patch fixes the CMA aligned offset calculation. > > Cc: [email protected] > Signed-off-by: Danesh Petigara <[email protected]> > Reviewed-by: Gregory Fong <[email protected]>
Acked-by: Michal Nazarewicz <[email protected]> > --- > mm/cma.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/mm/cma.c b/mm/cma.c > index 75016fd..58f37bd 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -70,9 +70,13 @@ static unsigned long cma_bitmap_aligned_offset(struct cma > *cma, int align_order) > > if (align_order <= cma->order_per_bit) > return 0; > - alignment = 1UL << (align_order - cma->order_per_bit); > - return ALIGN(cma->base_pfn, alignment) - > - (cma->base_pfn >> cma->order_per_bit); > + > + /* > + * Find a PFN aligned to the specified order and return > + * an offset represented in order_per_bits. > + */ It probably makes sense to move this comment outside of the function as function documentation. > + return (ALIGN(cma->base_pfn, (1UL << align_order)) > + - cma->base_pfn) >> cma->order_per_bit; > } > > static unsigned long cma_bitmap_maxno(struct cma *cma) > -- > 1.9.1 > -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +--<[email protected]>--<xmpp:[email protected]>--ooO--(_)--Ooo-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
