Re: [PATCH v1 02/29] virtio-mem: simplify calculation in virtio_mem_mb_state_prepare_next_mb()

From: David Hildenbrand
Date: Fri Oct 16 2020 - 05:00:34 EST


On 15.10.20 22:24, Pankaj Gupta wrote:
>> We actually need one byte less (next_mb_id is exclusive, first_mb_id is
>> inclusive). Simplify.
>>
>> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
>> Cc: Jason Wang <jasowang@xxxxxxxxxx>
>> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
>> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
>> ---
>> drivers/virtio/virtio_mem.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
>> index a1f5bf7a571a..670b3faf412d 100644
>> --- a/drivers/virtio/virtio_mem.c
>> +++ b/drivers/virtio/virtio_mem.c
>> @@ -257,8 +257,8 @@ static enum virtio_mem_mb_state virtio_mem_mb_get_state(struct virtio_mem *vm,
>> */
>> static int virtio_mem_mb_state_prepare_next_mb(struct virtio_mem *vm)
>> {
>> - unsigned long old_bytes = vm->next_mb_id - vm->first_mb_id + 1;
>> - unsigned long new_bytes = vm->next_mb_id - vm->first_mb_id + 2;
>> + unsigned long old_bytes = vm->next_mb_id - vm->first_mb_id;
>> + unsigned long new_bytes = old_bytes + 1;
>
> Maybe we can avoid new_bytes & old_bytes variables, instead use single
> variable. Can later be used with PFN_UP/PFN_DOWN.

I'll see if it fits into a single line now - if it does, I'll move it
there. Thanks!

--
Thanks,

David / dhildenb