linux-kernel - [PATCH v2 01/10] dmaengine: idxd: Fix lockdep warnings when calling idxd_device

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Message-Id: <20250821-idxd-fix-flr-on-kernel-queues-v3-v2-1-595d48fa065c@intel.com>
Date: Thu, 21 Aug 2025 15:59:35 -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 v2 01/10] dmaengine: idxd: Fix lockdep warnings when
 calling idxd_device_config()

Move the check for IDXD_FLAG_CONFIGURABLE and the locking to "inside"
idxd_device_config(), as this is common to all callers, and the one
that wasn't holding the lock was an error (that was causing the
lockdep warning).

Suggested-by: Dave Jiang <dave.jiang@...el.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@...el.com>
---
 drivers/dma/idxd/device.c | 17 +++++++----------
 drivers/dma/idxd/init.c   | 10 ++++------
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 5cf419fe6b46..ac41889e4fe1 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1107,7 +1107,11 @@ int idxd_device_config(struct idxd_device *idxd)
 {
 	int rc;
 
-	lockdep_assert_held(&idxd->dev_lock);
+	guard(spinlock)(&idxd->dev_lock);
+
+	if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
+		return 0;
+
 	rc = idxd_wqs_setup(idxd);
 	if (rc < 0)
 		return rc;
@@ -1434,11 +1438,7 @@ int idxd_drv_enable_wq(struct idxd_wq *wq)
 		}
 	}
 
-	rc = 0;
-	spin_lock(&idxd->dev_lock);
-	if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
-		rc = idxd_device_config(idxd);
-	spin_unlock(&idxd->dev_lock);
+	rc = idxd_device_config(idxd);
 	if (rc < 0) {
 		dev_dbg(dev, "Writing wq %d config failed: %d\n", wq->id, rc);
 		goto err;
@@ -1534,10 +1534,7 @@ int idxd_device_drv_probe(struct idxd_dev *idxd_dev)
 	}
 
 	/* Device configuration */
-	spin_lock(&idxd->dev_lock);
-	if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
-		rc = idxd_device_config(idxd);
-	spin_unlock(&idxd->dev_lock);
+	rc = idxd_device_config(idxd);
 	if (rc < 0)
 		return -ENXIO;
 
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index f98aa41fa42e..c25bd0595561 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -1092,12 +1092,10 @@ static void idxd_reset_done(struct pci_dev *pdev)
 	idxd_device_config_restore(idxd, idxd->idxd_saved);
 
 	/* Re-configure IDXD device if allowed. */
-	if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
-		rc = idxd_device_config(idxd);
-		if (rc < 0) {
-			dev_err(dev, "HALT: %s config fails\n", idxd_name);
-			goto out;
-		}
+	rc = idxd_device_config(idxd);
+	if (rc < 0) {
+		dev_err(dev, "HALT: %s config fails\n", idxd_name);
+		goto out;
 	}
 
 	/* Bind IDXD device to driver. */

-- 
2.50.1