linux-kernel - [PATCH resend] staging: rts5208: Remove unnecessary synchronize_irq() before free

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Date:	Sat, 30 Jan 2016 15:44:43 +0100
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Micky Ching <micky_ching@...lsil.com.cn>,
	devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
	Lars-Peter Clausen <lars@...afoo.de>
Subject: [PATCH resend] staging: rts5208: Remove unnecessary synchronize_irq() before free_irq()

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.

Patch was generated using the following semantic patch:
// <smpl>
@@
expression irq;
@@
-synchronize_irq(irq);
 free_irq(irq, ...);
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>
---
 drivers/staging/rts5208/rtsx.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/staging/rts5208/rtsx.c b/drivers/staging/rts5208/rtsx.c
index 1fe8e3e..5dfcdfb 100644
--- a/drivers/staging/rts5208/rtsx.c
+++ b/drivers/staging/rts5208/rtsx.c
@@ -320,7 +320,6 @@ static int rtsx_suspend(struct pci_dev *pci, pm_message_t state)
 	rtsx_do_before_power_down(chip, PM_S3);
 
 	if (dev->irq >= 0) {
-		synchronize_irq(dev->irq);
 		free_irq(dev->irq, (void *)dev);
 		dev->irq = -1;
 	}
@@ -398,7 +397,6 @@ static void rtsx_shutdown(struct pci_dev *pci)
 	rtsx_do_before_power_down(chip, PM_S1);
 
 	if (dev->irq >= 0) {
-		synchronize_irq(dev->irq);
 		free_irq(dev->irq, (void *)dev);
 		dev->irq = -1;
 	}
-- 
2.1.4