[PATCH 1/2] b43: Remove unnecessary synchronize_irq() before free_irq()

[PATCH 1/2] b43: Remove unnecessary synchronize_irq() before free_irq()

[Lars-Peter Clausen]

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@metafoo.de>
---
 drivers/net/wireless/broadcom/b43/main.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/broadcom/b43/main.c b/drivers/net/wireless/broadcom/b43/main.c
index c279211..72380af 100644
--- a/drivers/net/wireless/broadcom/b43/main.c
+++ b/drivers/net/wireless/broadcom/b43/main.c
@@ -4375,12 +4375,10 @@ redo:
 	/* Synchronize and free the interrupt handlers. Unlock to avoid deadlocks. */
 	orig_dev = dev;
 	mutex_unlock(&wl->mutex);
-	if (b43_bus_host_is_sdio(dev->dev)) {
+	if (b43_bus_host_is_sdio(dev->dev))
 		b43_sdio_free_irq(dev);
-	} else {
-		synchronize_irq(dev->dev->irq);
+	else
 		free_irq(dev->dev->irq, dev);
-	}
 	mutex_lock(&wl->mutex);
 	dev = wl->current_dev;
 	if (!dev)
-- 
2.1.4

[PATCH 2/2] rtlwifi: Remove unnecessary synchronize_irq() before free_irq()

[Lars-Peter Clausen]

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@metafoo.de>
---
 drivers/net/wireless/realtek/rtlwifi/pci.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/pci.c b/drivers/net/wireless/realtek/rtlwifi/pci.c
index 7f471bf..140d254 100644
--- a/drivers/net/wireless/realtek/rtlwifi/pci.c
+++ b/drivers/net/wireless/realtek/rtlwifi/pci.c
@@ -2392,7 +2392,6 @@ void rtl_pci_disconnect(struct pci_dev *pdev)
 	rtlpriv->cfg->ops->deinit_sw_vars(hw);
 
 	if (rtlpci->irq_alloc) {
-		synchronize_irq(rtlpci->pdev->irq);
 		free_irq(rtlpci->pdev->irq, hw);
 		rtlpci->irq_alloc = 0;
 	}
-- 
2.1.4

[PATCH 2/2] rtlwifi: Remove unnecessary synchronize_irq() before free_irq()

[Larry Finger]

On 02/08/2016 02:41 PM, Lars-Peter Clausen wrote:
> 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@metafoo.de>
> ---
>   drivers/net/wireless/realtek/rtlwifi/pci.c | 1 -
>   1 file changed, 1 deletion(-)
>
> diff --git a/drivers/net/wireless/realtek/rtlwifi/pci.c b/drivers/net/wireless/realtek/rtlwifi/pci.c
> index 7f471bf..140d254 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/pci.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/pci.c
> @@ -2392,7 +2392,6 @@ void rtl_pci_disconnect(struct pci_dev *pdev)
>   	rtlpriv->cfg->ops->deinit_sw_vars(hw);
>
>   	if (rtlpci->irq_alloc) {
> -		synchronize_irq(rtlpci->pdev->irq);
>   		free_irq(rtlpci->pdev->irq, hw);
>   		rtlpci->irq_alloc = 0;
>   	}
>

Acked-by: Larry Finger <Larry.Finger@lwfinger.net>

Makes sense to me.

Thanks,

Larry

[PATCH 1/2] b43: Remove unnecessary synchronize_irq() before free_irq()

[Michael Büsch]

On Mon,  8 Feb 2016 21:41:12 +0100
Lars-Peter Clausen <lars@metafoo.de> wrote:

> Calling synchronize_irq() right before free_irq() is quite useless. On one
> hand the IRQ can easily fire again before free_irq() is entered,

Well, that depends on whether the interrupt is shared and whether we
disabled the interrupt mask inside of the device (which we did).

> 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.

Ok, fair enough.

-- 
Michael
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[1/2] b43: Remove unnecessary synchronize_irq() before free_irq()

[Kalle Valo]

> 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@metafoo.de>

Thanks, 2 patches applied to wireless-drivers-next.git:

10fbc7cf031d b43: Remove unnecessary synchronize_irq() before free_irq()
400b43c58269 rtlwifi: Remove unnecessary synchronize_irq() before free_irq()

Kalle Valo