linux-kernel - [PATCH 4/9] dmaengine: idxd: Flush kernel workqueues on Field Level Reset

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Message-Id: <20250804-idxd-fix-flr-on-kernel-queues-v3-v1-4-4e020fbf52c1@intel.com>
Date: Mon, 04 Aug 2025 18:27:55 -0700
From: Vinicius Costa Gomes <vinicius.gomes@...el.com>
To: Dave Jiang <dave.jiang@...el.com>, Vinod Koul <vkoul@...nel.org>, 
 Fenghua Yu <fenghua.yu@...el.com>, Dan Williams <dan.j.williams@...el.com>
Cc: dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Vinicius Costa Gomes <vinicius.gomes@...el.com>
Subject: [PATCH 4/9] dmaengine: idxd: Flush kernel workqueues on Field
 Level Reset

When a Field Level Reset (FLR) happens terminate the pending
descriptors that were issued by in-kernel users and disable the
interrupts associated with those. They will be re-enabled after FLR
finishes.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@...el.com>
---
 drivers/dma/idxd/device.c | 24 ++++++++++++++++++++++++
 drivers/dma/idxd/idxd.h   |  1 +
 drivers/dma/idxd/irq.c    |  5 +++++
 3 files changed, 30 insertions(+)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index c599a902767ee9904d75a0510a911596e35a259b..287cf3bf1f5a2efdc9037968e9a4eed506e489c3 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1315,6 +1315,11 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
 
 	free_irq(ie->vector, ie);
 	idxd_flush_pending_descs(ie);
+
+	/* The interrupt might have been already released by FLR */
+	if (ie->int_handle == INVALID_INT_HANDLE)
+		return;
+
 	if (idxd->request_int_handles)
 		idxd_device_release_int_handle(idxd, ie->int_handle, IDXD_IRQ_MSIX);
 	idxd_device_clear_perm_entry(idxd, ie);
@@ -1323,6 +1328,25 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
 	ie->pasid = IOMMU_PASID_INVALID;
 }
 
+void idxd_wqs_flush_descs(struct idxd_device *idxd)
+{
+	struct idxd_wq *wq;
+	int i;
+
+	for (i = 0; i < idxd->max_wqs; i++) {
+		wq = idxd->wqs[i];
+		if (wq->state == IDXD_WQ_ENABLED && wq->type == IDXD_WQT_KERNEL) {
+			struct idxd_irq_entry *ie = &wq->ie;
+
+			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);
+			ie->int_handle = INVALID_INT_HANDLE;
+		}
+	}
+}
+
 int idxd_wq_request_irq(struct idxd_wq *wq)
 {
 	struct idxd_device *idxd = wq->idxd;
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 74e6695881e6f1684512601ca2c2ee241aaf0a78..6ccca3c56556dbffe0a7c983a2f11f6c73ff2bfd 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -737,6 +737,7 @@ static inline void idxd_desc_complete(struct idxd_desc *desc,
 int idxd_register_devices(struct idxd_device *idxd);
 void idxd_unregister_devices(struct idxd_device *idxd);
 void idxd_wqs_quiesce(struct idxd_device *idxd);
+void idxd_wqs_flush_descs(struct idxd_device *idxd);
 bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc);
 void multi_u64_to_bmap(unsigned long *bmap, u64 *val, int count);
 int idxd_load_iaa_device_defaults(struct idxd_device *idxd);
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 74059fe43fafeb930f58db21d3824f62b095b968..26547586fcfaa1b9d244b678bf8e209b7b14d35a 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -417,6 +417,11 @@ static irqreturn_t idxd_halt(struct idxd_device *idxd)
 		} else if (gensts.reset_type == IDXD_DEVICE_RESET_FLR) {
 			idxd->state = IDXD_DEV_HALTED;
 			idxd_mask_error_interrupts(idxd);
+			/* Flush all pending descriptors, and disable
+			 * interrupts, they will be re-enabled when FLR
+			 * concludes.
+			 */
+			idxd_wqs_flush_descs(idxd);
 			dev_dbg(&idxd->pdev->dev,
 				"idxd halted, doing FLR. After FLR, configs are restored\n");
 			INIT_WORK(&idxd->work, idxd_device_flr);

-- 
2.50.1