Commit 7d6b61c3 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Wolfram Sang
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i2c: i801: Use PCI bus rescan mutex to protect P2SB access 

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: 1a987c69 ("i2c: i801: make p2sb_spinlock a mutex")
Reported-by: default avatarAndy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: default avatarJean Delvare <jdelvare@suse.de>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 4c591063

drivers/i2c/busses/i2c-i801.c

+2 −3
Original line number Diff line number Diff line
@@ -1485,7 +1485,6 @@ 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;
@@ -1498,7 +1497,7 @@ 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);
@@ -1516,7 +1515,7 @@ 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)