From: Heiner Kallweit Date: Sun, 5 Sep 2021 15:59:42 +0000 (+0200) Subject: i2c: i801: Use PCI bus rescan mutex to protect P2SB access X-Git-Tag: accepted/tizen/unified/20230118.172025~5366 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c31b0fe8e116354cbfbea52e49a29095f42ec9bd;p=platform%2Fkernel%2Flinux-rpi.git i2c: i801: Use PCI bus rescan mutex to protect P2SB access [ Upstream commit 7d6b61c394a42b8385858bb9e306d48a0112823c ] 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 Signed-off-by: Heiner Kallweit Reviewed-by: Andy Shevchenko Reviewed-by: Jean Delvare Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 89ae78ef..1f929e6 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)