[PATCH 6/6] dmaengine: idxd: Do not release interrupt handles on terminate_all

[Vinicius Costa Gomes]

idxd_wq_flush_descs() is called from the dmaengine .device_terminate_all
path, but besides flushing the pending descriptors it also releases the
interrupt handle. As the workqueue stays enabled, the handle is never
re-armed, and any subsequent submission uses an invalid handle and never
completes.

This only shows up when the same workqueue is used more than once: the
first run leaves the handle released on terminate_all, so any later run
times out on every descriptor. dmatest reproduces it by running twice.

Split the interrupt handle teardown into idxd_wq_release_int_handle() so
that terminate_all only flushes descriptors. The FLR path still needs
both, so call them together there.

Fixes: 2a93f5747d0e ("dmaengine: idxd: Flush all pending descriptors")
Reported-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
---
 drivers/dma/idxd/device.c | 11 ++++++++++-
 drivers/dma/idxd/idxd.h   |  1 +
 drivers/dma/idxd/irq.c    |  1 +
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 131138483b87..06299f40f531 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1349,6 +1349,16 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
 }
 
 void idxd_wq_flush_descs(struct idxd_wq *wq)
+{
+	guard(mutex)(&wq->wq_lock);
+
+	if (wq->state != IDXD_WQ_ENABLED || wq->type != IDXD_WQT_KERNEL)
+		return;
+
+	idxd_flush_pending_descs(&wq->ie);
+}
+
+void idxd_wq_release_int_handle(struct idxd_wq *wq)
 {
 	struct idxd_irq_entry *ie = &wq->ie;
 	struct idxd_device *idxd = wq->idxd;
@@ -1358,7 +1368,6 @@ void idxd_wq_flush_descs(struct idxd_wq *wq)
 	if (wq->state != IDXD_WQ_ENABLED || wq->type != IDXD_WQT_KERNEL)
 		return;
 
-	idxd_flush_pending_descs(ie);
 	if (idxd->request_int_handles)
 		idxd_device_release_int_handle(idxd, ie->int_handle, IDXD_IRQ_MSIX);
 	idxd_device_clear_perm_entry(idxd, ie);
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index ce78b9a7c641..f4aed90560e0 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -804,6 +804,7 @@ int idxd_wq_init_percpu_ref(struct idxd_wq *wq);
 void idxd_wq_free_irq(struct idxd_wq *wq);
 int idxd_wq_request_irq(struct idxd_wq *wq);
 void idxd_wq_flush_descs(struct idxd_wq *wq);
+void idxd_wq_release_int_handle(struct idxd_wq *wq);
 
 /* submission */
 int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc);
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 6a25e1fd0e62..26d75d744797 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -405,6 +405,7 @@ static void idxd_wqs_flush_descs(struct idxd_device *idxd)
 		struct idxd_wq *wq = idxd->wqs[i];
 
 		idxd_wq_flush_descs(wq);
+		idxd_wq_release_int_handle(wq);
 	}
 }
 

-- 
2.56.0