[PATCH 02/11] NTB: ntb_transport: Start TX offload thread after queue setup

[Koichiro Den]

ntb_transport_create_queue() starts the per-QP TX offload thread before
DMA mappings and queue entries are allocated. If later setup fails, the
error path returns the QP to the free bitmap without stopping the
thread. A retry can then reinitialize its waitqueue while the old thread
is still waiting on it.

Start the thread after queue setup.

Fixes: 322617a06c97 ("NTB: ntb_transport: Add 'tx_memcpy_offload' module option")
Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
---
Originally submitted as part of the direct TX/RX series v1:
https://lore.kernel.org/r/20260810165136.2292436-4-den@xxxxxxxxxxxxx/

 drivers/ntb/ntb_transport.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 3389d6ca9ebd..55a20ae9a85e 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -2055,20 +2055,6 @@ ntb_transport_create_queue(void *data, struct device *client_dev,
 	qp->tx_handler = handlers->tx_handler;
 	qp->event_handler = handlers->event_handler;
 
-	init_waitqueue_head(&qp->tx_offload_wq);
-	if (tx_memcpy_offload) {
-		qp->tx_offload_thread = kthread_run(ntb_tx_memcpy_kthread, qp,
-						    "ntb-txcpy/%s/%u",
-						    pci_name(ndev->pdev), qp->qp_num);
-		if (IS_ERR(qp->tx_offload_thread)) {
-			dev_warn(&nt->ndev->dev,
-				 "tx memcpy offload thread creation failed: %ld; falling back to inline copy\n",
-				 PTR_ERR(qp->tx_offload_thread));
-			qp->tx_offload_thread = NULL;
-		}
-	} else
-		qp->tx_offload_thread = NULL;
-
 	dma_cap_zero(dma_mask);
 	dma_cap_set(DMA_MEMCPY, dma_mask);
 
@@ -2129,6 +2115,20 @@ ntb_transport_create_queue(void *data, struct device *client_dev,
 			     &qp->tx_free_q);
 	}
 
+	init_waitqueue_head(&qp->tx_offload_wq);
+	qp->tx_offload_thread = NULL;
+	if (tx_memcpy_offload) {
+		qp->tx_offload_thread = kthread_run(ntb_tx_memcpy_kthread, qp,
+						    "ntb-txcpy/%s/%u",
+						    pci_name(ndev->pdev), qp->qp_num);
+		if (IS_ERR(qp->tx_offload_thread)) {
+			dev_warn(&nt->ndev->dev,
+				 "tx memcpy offload thread creation failed: %ld; falling back to inline copy\n",
+				 PTR_ERR(qp->tx_offload_thread));
+			qp->tx_offload_thread = NULL;
+		}
+	}
+
 	ntb_db_clear(qp->ndev, qp_bit);
 	ntb_db_clear_mask(qp->ndev, qp_bit);
 
-- 
2.51.0