linux-kernel - Re: [PATCH] PCI: Remove redundant pci_dev_unlock() in pci_slot

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Message-ID: <360c5c8e-dfc7-a88b-fa20-a157da87ea74@linux.intel.com>
Date: Thu, 11 Dec 2025 20:13:59 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Jinhui Guo <guojinhui.liam@...edance.com>
cc: bhelgaas@...gle.com, kbusch@...nel.org, dave.jiang@...el.com, 
    dan.j.williams@...el.com, linux-pci@...r.kernel.org, 
    LKML <linux-kernel@...r.kernel.org>, stable@...r.kernel.org
Subject: Re: [PATCH] PCI: Remove redundant pci_dev_unlock() in
 pci_slot_trylock()

On Thu, 11 Dec 2025, Jinhui Guo wrote:

> Commit a4e772898f8b ("PCI: Add missing bridge lock to pci_bus_lock()")
> delegates the bridge device's pci_dev_trylock() to pci_bus_trylock()
> in pci_slot_trylock(), but it leaves a redundant pci_dev_unlock() when
> pci_bus_trylock() fails.
> 
> Remove the redundant bridge-device pci_dev_unlock() in pci_slot_trylock(),
> since that lock is no longer taken there.

Doesn't it cause issues if trying to unlock something that wasn't locked 
so saying its "redundant" seem a bit an understatement?

> Fixes: a4e772898f8b ("PCI: Add missing bridge lock to pci_bus_lock()")
> Cc: stable@...r.kernel.org
> Signed-off-by: Jinhui Guo <guojinhui.liam@...edance.com>
> ---
>  drivers/pci/pci.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 13dbb405dc31..75a98819db6f 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -5347,7 +5347,6 @@ static int pci_slot_trylock(struct pci_slot *slot)
>  			continue;
>  		if (dev->subordinate) {
>  			if (!pci_bus_trylock(dev->subordinate)) {
> -				pci_dev_unlock(dev);
>  				goto unlock;
>  			}
>  		} else if (!pci_dev_trylock(dev))
> 

-- 
 i.