ublk: move check for empty address field on command submission

In preparation for zoned storage support, move the check for empty `addr`
field into the command handler case statement. Note that the check makes no
sense for `UBLK_IO_NEED_GET_DATA` because the `addr` field must always be
set for this command.

Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230804114610.179530-3-nmi@metaspace.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/ublk_drv.c

@@ -1419,11 +1419,6 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
 		goto out;
 
-	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	ret = ublk_check_cmd_op(cmd_op);
 	if (ret)
 		goto out;
@@ -1450,6 +1445,10 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 			 */
 			if (!ub_cmd->addr && !ublk_need_get_data(ubq))
 				goto out;
+		} else if (ub_cmd->addr) {
+			/* User copy requires addr to be unset */
+			ret = -EINVAL;
+			goto out;
 		}
 
 		ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
@@ -1469,7 +1468,12 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 			if (!ub_cmd->addr && (!ublk_need_get_data(ubq) ||
 						req_op(req) == REQ_OP_READ))
 				goto out;
+		} else if (ub_cmd->addr) {
+			/* User copy requires addr to be unset */
+			ret = -EINVAL;
+			goto out;
 		}
+
 		ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
 		ublk_commit_completion(ub, ub_cmd);
 		break;