From a28e35171cb1ff84197e8d271b65aaeb8c404827 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Fri, 22 Jan 2016 14:12:02 +0100 Subject: [PATCH] i2c: piix4: Fix SB800 locking We need a single mutex for all 4 shared SMBus ports on the SB800. A per-port mutex doesn't protect us from concurrent access. In theory the mutex should be per PCI device, however in practice we know that there's only ever a single instance of the device in a given system so we can use a global. Also take the mutex during initialization, as first port may be already in use when second port is initialized. Signed-off-by: Jean Delvare Tested-by: Christian Fetzer Reviewed-by: Mika Westerberg [wsa: made mutex static] Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-piix4.c | 22 ++++++---------------- 1 file changed, 6 insertions(+), 16 deletions(-) diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c index e04598595073..5fd7505b9018 100644 --- a/drivers/i2c/busses/i2c-piix4.c +++ b/drivers/i2c/busses/i2c-piix4.c @@ -137,6 +137,7 @@ static const struct dmi_system_id piix4_dmi_ibm[] = { }; /* SB800 globals */ +static DEFINE_MUTEX(piix4_mutex_sb800); static const char *piix4_main_port_names_sb800[PIIX4_MAX_ADAPTERS] = { "SDA0", "SDA2", "SDA3", "SDA4" }; @@ -148,7 +149,6 @@ struct i2c_piix4_adapdata { /* SB800 */ bool sb800_main; unsigned short port; - struct mutex *mutex; }; static int piix4_setup(struct pci_dev *PIIX4_dev, @@ -275,10 +275,12 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev, else smb_en = (aux) ? 0x28 : 0x2c; + mutex_lock(&piix4_mutex_sb800); outb_p(smb_en, SB800_PIIX4_SMB_IDX); smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1); outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX); smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1); + mutex_unlock(&piix4_mutex_sb800); if (!smb_en) { smb_en_status = smba_en_lo & 0x10; @@ -559,7 +561,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, u8 port; int retval; - mutex_lock(adapdata->mutex); + mutex_lock(&piix4_mutex_sb800); outb_p(SB800_PIIX4_PORT_IDX, SB800_PIIX4_SMB_IDX); smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1); @@ -574,7 +576,7 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1); - mutex_unlock(adapdata->mutex); + mutex_unlock(&piix4_mutex_sb800); return retval; } @@ -673,17 +675,10 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba, static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba) { - struct mutex *mutex; struct i2c_piix4_adapdata *adapdata; int port; int retval; - mutex = kzalloc(sizeof(*mutex), GFP_KERNEL); - if (mutex == NULL) - return -ENOMEM; - - mutex_init(mutex); - for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) { retval = piix4_add_adapter(dev, smba, piix4_main_port_names_sb800[port], @@ -696,7 +691,6 @@ static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba) adapdata = i2c_get_adapdata(piix4_main_adapters[port]); adapdata->sb800_main = true; adapdata->port = port; - adapdata->mutex = mutex; } return retval; @@ -714,8 +708,6 @@ error: } } - kfree(mutex); - return retval; } @@ -798,10 +790,8 @@ static void piix4_adap_remove(struct i2c_adapter *adap) i2c_del_adapter(adap); if (adapdata->port == 0) { release_region(adapdata->smba, SMBIOSIZE); - if (adapdata->sb800_main) { - kfree(adapdata->mutex); + if (adapdata->sb800_main) release_region(SB800_PIIX4_SMB_IDX, 2); - } } kfree(adapdata); kfree(adap); -- 2.20.1