From: Gonglei <arei.gong...@huawei.com>
1. avoid possible superflous checking
2. make code more robustness
Signed-off-by: Gonglei <arei.gong...@huawei.com>
---
v2: address Paolo's comments, thanks.
---
hw/block/virtio-blk.c | 27 +++++++++------------------
1 file changed, 9 insertions(+), 18 deletions(-)
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 093e475..21f8d72 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -404,24 +404,15 @@ void virtio_blk_submit_multireq(BlockBackend *blk,
MultiReqBuffer *mrb)
for (i = 0; i < mrb->num_reqs; i++) {
VirtIOBlockReq *req = mrb->reqs[i];
if (num_reqs > 0) {
- bool merge = true;
-
- /* merge would exceed maximum number of IOVs */
- if (niov + req->qiov.niov > IOV_MAX) {
- merge = false;
- }
-
- /* merge would exceed maximum transfer length of backend device */
- if (req->qiov.size / BDRV_SECTOR_SIZE + nb_sectors > max_xfer_len)
{
- merge = false;
- }
-
- /* requests are not sequential */
- if (sector_num + nb_sectors != req->sector_num) {
- merge = false;
- }
-
- if (!merge) {
+ /*
+ * NOTE: We cannot merge the requests in below situations:
+ * 1. requests are not sequential
+ * 2. merge would exceed maximum number of IOVs
+ * 3. merge would exceed maximum transfer length of backend device
+ */
+ if (sector_num + nb_sectors != req->sector_num ||
+ niov > IOV_MAX - req->qiov.niov ||
+ req->qiov.size / BDRV_SECTOR_SIZE + nb_sectors > max_xfer_len)
{
submit_requests(blk, mrb, start, num_reqs, niov);
num_reqs = 0;
}
--
1.7.12.4
