[PATCH v2 2/2] ublk: clear auto buf reg before updating io->buf in batch commit

ublk_batch_commit_io() stored the new auto_buf into io->buf before
calling ublk_clear_auto_buf_reg(). Clear takes the unregister index
from io->buf.auto_reg, so it could drop the new slot and leave the
old registered buffer behind.

Fixes: 1e500e106d5a ("ublk: handle UBLK_U_IO_COMMIT_IO_CMDS")
Signed-off-by: Yang Xiuwei <[email protected]>
---
 drivers/block/ublk_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 041bd3ea023f..e12bc4ee74d3 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -3782,11 +3782,11 @@ static int ublk_batch_commit_io(struct ublk_queue *ubq,
 	ret = ublk_batch_commit_io_check(ubq, io, &buf);
 	if (!ret) {
 		io->res = elem->result;
-		io->buf = buf;
 		req = ublk_fill_io_cmd(io, data->cmd);
 
 		if (auto_reg)
 			ublk_clear_auto_buf_reg(io, data->cmd, &buf_idx);
+		io->buf = buf;
 		compl = ublk_need_complete_req(data->ub, io);
 	}
 	ublk_io_unlock(io);
-- 
2.25.1