[PATCH v2 02/29] virtio-mem: more precise calculation in virtio_mem_mb_state_prepare_next_mb()

David Hildenbrand
2020-11-12T13:38:37Z

We actually need one byte less (next_mb_id is exclusive, first_mb_id is
inclusive). While at it, compact the code.

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
drivers/virtio/virtio_mem.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index a37fd73588da..dee46865bae2 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -257,10 +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;
- int old_pages = PFN_UP(old_bytes);
- int new_pages = PFN_UP(new_bytes);
+ int old_pages = PFN_UP(vm->next_mb_id - vm->first_mb_id);
+ int new_pages = PFN_UP(vm->next_mb_id - vm->first_mb_id + 1);
uint8_t *new_mb_state;

if (vm->mb_state && old_pages == new_pages)
--
2.26.2