From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: [PATCH] i2c-piix4: Fix SB800 locking Date: Fri, 22 Jan 2016 14:12:02 +0100 Message-ID: <20160122141202.09c94802@endymion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:48848 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753369AbcAVNMG (ORCPT ); Fri, 22 Jan 2016 08:12:06 -0500 Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Linux I2C Cc: Christian Fetzer , Mika Westerberg , Andy Shevchenko , Wolfram Sang 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 Cc: Christian Fetzer Cc: Mika Westerberg Cc: Andy Shevchenko Cc: Wolfram Sang --- drivers/i2c/busses/i2c-piix4.c | 22 ++++++---------------- 1 file changed, 6 insertions(+), 16 deletions(-) --- linux-4.5-rc0.orig/drivers/i2c/busses/i2c-piix4.c 2016-01-22 13:51:27.500458587 +0100 +++ linux-4.5-rc0/drivers/i2c/busses/i2c-piix4.c 2016-01-22 13:56:13.210960522 +0100 @@ -137,6 +137,7 @@ static const struct dmi_system_id piix4_ }; /* SB800 globals */ +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_ 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 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 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_ 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(stru 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 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); -- Jean Delvare SUSE L3 Support