On 2/24/2015 1:10 PM, Michal Nazarewicz wrote: > On Tue, Feb 24 2015, Danesh Petigara <dpetigara@xxxxxxxxxxxx> 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: stable@xxxxxxxxxxxxxxx >> Signed-off-by: Danesh Petigara <dpetigara@xxxxxxxxxxxx> >> Reviewed-by: Gregory Fong <gregory.0xf0@xxxxxxxxx> > > Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx> > >> --- >> 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. > Thanks for the feedback. Will send out patch v2 with the comment moved outside the function and also remove the unused 'alignment' variable. >> + 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, Danesh Petigara -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>