batch io is designed to be independent of task context, and we will not
track task context for batch io feature.

So warn on non-batch-io code paths.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/block/ublk_drv.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index a0dfad8a56f0..46be5b656f22 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -261,6 +261,11 @@ static inline bool ublk_dev_support_batch_io(const struct ublk_device *ub)
 	return false;
 }
 
+static inline bool ublk_support_batch_io(const struct ublk_queue *ubq)
+{
+	return false;
+}
+
 static inline struct ublksrv_io_desc *
 ublk_get_iod(const struct ublk_queue *ubq, unsigned tag)
 {
@@ -1309,6 +1314,8 @@ static void ublk_dispatch_req(struct ublk_queue *ubq,
 			__func__, ubq->q_id, req->tag, io->flags,
 			ublk_get_iod(ubq, req->tag)->addr);
 
+	WARN_ON_ONCE(ublk_support_batch_io(ubq));
+
 	/*
 	 * Task is exiting if either:
 	 *
@@ -1868,6 +1875,8 @@ static void ublk_uring_cmd_cancel_fn(struct io_uring_cmd *cmd,
 	if (WARN_ON_ONCE(pdu->tag >= ubq->q_depth))
 		return;
 
+	WARN_ON_ONCE(ublk_support_batch_io(ubq));
+
 	task = io_uring_cmd_get_task(cmd);
 	io = &ubq->ios[pdu->tag];
 	if (WARN_ON_ONCE(task && task != io->task))
@@ -2233,7 +2242,10 @@ static int __ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
 
 	ublk_fill_io_cmd(io, cmd);
 
-	WRITE_ONCE(io->task, get_task_struct(current));
+	if (ublk_support_batch_io(ubq))
+		WRITE_ONCE(io->task, NULL);
+	else
+		WRITE_ONCE(io->task, get_task_struct(current));
 	ublk_mark_io_ready(ub, ubq);
 out:
 	return ret;
@@ -2347,6 +2359,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 	if (tag >= ubq->q_depth)
 		goto out;
 
+	WARN_ON_ONCE(ublk_support_batch_io(ubq));
+
 	io = &ubq->ios[tag];
 	/* UBLK_IO_FETCH_REQ can be handled on any task, which sets io->task */
 	if (unlikely(_IOC_NR(cmd_op) == UBLK_IO_FETCH_REQ)) {
-- 
2.47.0