linux-kernel - [PATCH] dmaengine: idxd: Remove unnecessary synchronize_irq() before free

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Date:   Fri, 13 May 2022 08:16:22 +0000
From:   cgel.zte@...il.com
To:     dave.jiang@...el.com
Cc:     vkoul@...nel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, Minghao Chi <chi.minghao@....com.cn>,
        Zeal Robot <zealci@....com.cn>
Subject: [PATCH] dmaengine: idxd: Remove unnecessary synchronize_irq() before free_irq()

From: Minghao Chi <chi.minghao@....com.cn>

Calling synchronize_irq() right before free_irq() is quite useless. On one
hand the IRQ can easily fire again before free_irq() is entered, on the
other hand free_irq() itself calls synchronize_irq() internally (in a race
condition free way) before any state associated with the IRQ is freed.

Reported-by: Zeal Robot <zealci@....com.cn>
Signed-off-by: Minghao Chi <chi.minghao@....com.cn>
---
 drivers/dma/idxd/device.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 5363fb9218f2..9dd8e6bb21e6 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1179,7 +1179,6 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
 	struct idxd_device *idxd = wq->idxd;
 	struct idxd_irq_entry *ie = &wq->ie;
 
-	synchronize_irq(ie->vector);
 	free_irq(ie->vector, ie);
 	idxd_flush_pending_descs(ie);
 	if (idxd->request_int_handles)
--
2.25.1