[PATCH] octeontx2-pf: Remove unnecessary synchronize_irq() before free_irq()

[PATCH] octeontx2-pf: 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/net/ethernet/marvell/octeontx2/nic/otx2_pf.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
index 2b204c1c23de..4fad951b94df 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
@@ -1718,7 +1718,6 @@ int otx2_open(struct net_device *netdev)
 	vec = pci_irq_vector(pf->pdev,
 			     pf->hw.nix_msixoff + NIX_LF_QINT_VEC_START);
 	otx2_write64(pf, NIX_LF_QINTX_ENA_W1C(0), BIT_ULL(0));
-	synchronize_irq(vec);
 	free_irq(vec, pf);
 err_disable_napi:
 	otx2_disable_napi(pf);
@@ -1762,7 +1761,6 @@ int otx2_stop(struct net_device *netdev)
 	vec = pci_irq_vector(pf->pdev,
 			     pf->hw.nix_msixoff + NIX_LF_QINT_VEC_START);
 	otx2_write64(pf, NIX_LF_QINTX_ENA_W1C(0), BIT_ULL(0));
-	synchronize_irq(vec);
 	free_irq(vec, pf);
 
 	/* Cleanup CQ NAPI and IRQ */
--
2.25.1

Re: [PATCH] octeontx2-pf: Remove unnecessary synchronize_irq() before free_irq()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Fri, 13 May 2022 08:19:18 +0000 you 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.
> 
> [...]

Here is the summary with links:
  - octeontx2-pf: Remove unnecessary synchronize_irq() before free_irq()
    https://git.kernel.org/netdev/net-next/c/d887ae3247e0

You are awesome, thank you!
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