[PATCH] qedr: Remove unnecessary synchronize_irq() before free_irq()

[PATCH] qedr: Remove unnecessary synchronize_irq() before free_irq()

[cgel.zte]

From: Minghao Chi <chi.minghao@zte.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@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
---
 drivers/infiniband/hw/qedr/main.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/infiniband/hw/qedr/main.c b/drivers/infiniband/hw/qedr/main.c
index 65ce6d0f1885..5152f10d2e6d 100644
--- a/drivers/infiniband/hw/qedr/main.c
+++ b/drivers/infiniband/hw/qedr/main.c
@@ -500,7 +500,6 @@ static void qedr_sync_free_irqs(struct qedr_dev *dev)
 		if (dev->int_info.msix_cnt) {
 			idx = i * dev->num_hwfns + dev->affin_hwfn_idx;
 			vector = dev->int_info.msix[idx].vector;
-			synchronize_irq(vector);
 			free_irq(vector, &dev->cnq_array[i]);
 		}
 	}
--
2.25.1

RE: [EXT] [PATCH] qedr: Remove unnecessary synchronize_irq() before free_irq()

[Michal Kalderon]

> -----Original Message-----
> From: cgel.zte@gmail.com <cgel.zte@gmail.com>
> Sent: Friday, May 13, 2022 11:17 AM
> To: Michal Kalderon <mkalderon@marvell.com>
> Cc: Ariel Elior <aelior@marvell.com>; jgg@ziepe.ca; leon@kernel.org; linux-
> rdma@vger.kernel.org; linux-kernel@vger.kernel.org; Minghao Chi
> <chi.minghao@zte.com.cn>; Zeal Robot <zealci@zte.com.cn>
> Subject: [EXT] [PATCH] qedr: Remove unnecessary synchronize_irq() before
> free_irq()
> 
> External Email
> 
> ----------------------------------------------------------------------
> From: Minghao Chi <chi.minghao@zte.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@zte.com.cn>
> Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
> ---
>  drivers/infiniband/hw/qedr/main.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/infiniband/hw/qedr/main.c
> b/drivers/infiniband/hw/qedr/main.c
> index 65ce6d0f1885..5152f10d2e6d 100644
> --- a/drivers/infiniband/hw/qedr/main.c
> +++ b/drivers/infiniband/hw/qedr/main.c
> @@ -500,7 +500,6 @@ static void qedr_sync_free_irqs(struct qedr_dev
> *dev)
>  		if (dev->int_info.msix_cnt) {
>  			idx = i * dev->num_hwfns + dev->affin_hwfn_idx;
>  			vector = dev->int_info.msix[idx].vector;
> -			synchronize_irq(vector);
>  			free_irq(vector, &dev->cnq_array[i]);
>  		}
>  	}
> --
> 2.25.1
> 

Thanks, 

Acked-by: Michal Kalderon <michal.kalderon@marvell.com>

Re: [PATCH] qedr: Remove unnecessary synchronize_irq() before free_irq()

[Jason Gunthorpe]

On Fri, May 13, 2022 at 08:16:47AM +0000, cgel.zte@gmail.com wrote:
> From: Minghao Chi <chi.minghao@zte.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@zte.com.cn>
> Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
> Acked-by: Michal Kalderon <michal.kalderon@marvell.com>
> ---
>  drivers/infiniband/hw/qedr/main.c | 1 -
>  1 file changed, 1 deletion(-)

Applied to for-next, thanks

Jason