From: Jean Delvare <jdelvare@suse.de>
To: Heiner Kallweit <hkallweit1@gmail.com>
Cc: linux-i2c@vger.kernel.org, Andy Shevchenko <andriy.shevchenko@intel.com>
Subject: Re: [PATCH] i2c: i801: Use PCI bus rescan mutex to protect P2SB access
Date: Mon, 6 Sep 2021 11:21:04 +0200 [thread overview]
Message-ID: <20210906112104.5cda3131@endymion> (raw)
In-Reply-To: <7521c130-d777-6a26-bd14-1ed784f828cc@gmail.com>
Hi Heiner,
On Sun, 05 Sep 2021 17:59:42 +0200, Heiner Kallweit wrote:
> As pointed out by Andy in [0] using a local mutex here isn't strictly
> wrong but not sufficient. We should hold the PCI rescan lock for P2SB
> operations.
>
> [0] https://www.spinics.net/lists/linux-i2c/msg52717.html
>
> Fixes: 1a987c69ce2c ("i2c: i801: make p2sb_spinlock a mutex")
> Reported-by: Andy Shevchenko <andriy.shevchenko@intel.com>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> drivers/i2c/busses/i2c-i801.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 89ae78ef1..1f929e6c3 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -1493,7 +1493,6 @@ static struct platform_device *
> i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> struct resource *tco_res)
> {
> - static DEFINE_MUTEX(p2sb_mutex);
> struct resource *res;
> unsigned int devfn;
> u64 base64_addr;
> @@ -1506,7 +1505,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> * enumerated by the PCI subsystem, so we need to unhide/hide it
> * to lookup the P2SB BAR.
> */
> - mutex_lock(&p2sb_mutex);
> + pci_lock_rescan_remove();
>
> devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 1);
>
> @@ -1524,7 +1523,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> /* Hide the P2SB device, if it was hidden before */
> if (hidden)
> pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, hidden);
> - mutex_unlock(&p2sb_mutex);
> + pci_unlock_rescan_remove();
>
> res = &tco_res[1];
> if (pci_dev->device == PCI_DEVICE_ID_INTEL_DNV_SMBUS)
Looks good to me.
Reviewed-by: Jean Delvare <jdelvare@suse.de>
--
Jean Delvare
SUSE L3 Support
next prev parent reply other threads:[~2021-09-06 9:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-05 15:59 [PATCH] i2c: i801: Use PCI bus rescan mutex to protect P2SB access Heiner Kallweit
2021-09-06 8:30 ` Andy Shevchenko
2021-09-06 9:21 ` Jean Delvare [this message]
2021-09-29 20:13 ` Wolfram Sang
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