linux-kernel - [PATCH v3] dmaengine: idxd: force wq context cleanup on device disable path

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Date:   Tue, 28 Jun 2022 16:00:56 -0700
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     "Vinod Koul" <vkoul@...nel.org>,
        "Dave Jiang" <dave.jiang@...el.com>,
        "Tony Zhu" <tony.zhu@...el.com>, dmaengine@...r.kernel.org,
        "linux-kernel" <linux-kernel@...r.kernel.org>
Cc:     Fenghua Yu <fenghua.yu@...el.com>
Subject: [PATCH v3] dmaengine: idxd: force wq context cleanup on device disable path

From: Dave Jiang <dave.jiang@...el.com>

Testing shown that when a wq mode is setup to be dedicated and then torn
down and reconfigured to shared, the wq configured end up being dedicated
anyays. The root cause is when idxd_device_wqs_clear_state() gets called
during idxd_driver removal, idxd_wq_disable_cleanup() does not get called
vs when the wq driver is removed first. The check of wq state being
"enabled" causes the cleanup to be bypassed. However, idxd_driver->remove()
releases all wq drivers. So the wqs goes to "disabled" state and will never
be "enabled". By that point, the driver has no idea if the wq was
previously configured or clean. So force call idxd_wq_disable_cleanup() on
all wqs always to make sure everything gets cleaned up.

Reported-by: Tony Zhu <tony.zhu@...el.com>
Tested-by: Tony Zhu <tony.zhu@...el.com>
Fixes: 0dcfe41e9a4c ("dmanegine: idxd: cleanup all device related bits after disabling device")
Signed-off-by: Dave Jiang <dave.jiang@...el.com>
Co-developed-by: Fenghua Yu <fenghua.yu@...el.com>
Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
---
Change Log:
v3:
- Add Co-developed-by: and Signed-off-by: Fenghua Yu

v2:
- Re-based to 5.19-rc2 so that it can be applied cleanly. No functionality
  change.

v1:
https://patchwork.kernel.org/project/linux-dmaengine/patch/165090959239.1376825.18183942742142655091.stgit@djiang5-desk3.ch.intel.com/

 drivers/dma/idxd/device.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index ff0ea60051f0..5a8cc52c1abf 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -716,10 +716,7 @@ static void idxd_device_wqs_clear_state(struct idxd_device *idxd)
 		struct idxd_wq *wq = idxd->wqs[i];
 
 		mutex_lock(&wq->wq_lock);
-		if (wq->state == IDXD_WQ_ENABLED) {
-			idxd_wq_disable_cleanup(wq);
-			wq->state = IDXD_WQ_DISABLED;
-		}
+		idxd_wq_disable_cleanup(wq);
 		idxd_wq_device_reset_cleanup(wq);
 		mutex_unlock(&wq->wq_lock);
 	}
-- 
2.32.0