From bbd2d9c9198c6efd449e9d395b3eaf2d03aa3bba Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Thu, 26 Nov 2009 09:22:33 +0100 Subject: i2c: Fix userspace_device list corruption Fix userspace_device list corruption. The corruption was caused by clients not being removed when adapters with such clients were themselves removed. Something like the following would trigger it (assuming i2c-stub gets adapter number 3): # modprobe i2c-stub chip_addr=0x50 # echo 24c08 0x50 > /sys/bus/i2c/devices/i2c-3/new_device # rmmod i2c-stub # modprobe i2c-stub chip_addr=0x50 # echo 24c08 0x50 > /sys/bus/i2c/devices/i2c-3/new_device For the records, the stack trace in the kernel logs look like this: kernel: WARNING: at lib/list_debug.c:30 __list_add+0x8b/0x90() kernel: Hardware name: (...) kernel: list_add corruption. prev->next should be next (c137fc84), but was (null). (prev=f57111b8). kernel: Modules linked in: (...) kernel: Pid: 4669, comm: bash Not tainted 2.6.32-rc8 #259 kernel: Call Trace: kernel: [] ? __list_add+0x8b/0x90 kernel: [] ? __list_add+0x8b/0x90 kernel: [] warn_slowpath_common+0x6c/0xc0 kernel: [] ? __list_add+0x8b/0x90 kernel: [] warn_slowpath_fmt+0x26/0x30 kernel: [] __list_add+0x8b/0x90 kernel: [] i2c_sysfs_new_device+0x1c5/0x250 kernel: [] ? might_fault+0x2e/0x80 kernel: [] ? i2c_sysfs_new_device+0x0/0x250 kernel: [] dev_attr_store+0x25/0x30 kernel: [] sysfs_write_file+0x9c/0xf0 kernel: [] vfs_write+0x9c/0x160 kernel: [] ? sysfs_write_file+0x0/0xf0 kernel: [] sys_write+0x3d/0x70 kernel: [] sysenter_do_call+0x12/0x36 Signed-off-by: Jean Delvare --- drivers/i2c/i2c-core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/i2c/i2c-core.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 8d80fceca6a4..296504355142 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -762,6 +762,7 @@ int i2c_del_adapter(struct i2c_adapter *adap) { int res = 0; struct i2c_adapter *found; + struct i2c_client *client, *next; /* First make sure that this adapter was ever added */ mutex_lock(&core_lock); @@ -781,6 +782,16 @@ int i2c_del_adapter(struct i2c_adapter *adap) if (res) return res; + /* Remove devices instantiated from sysfs */ + list_for_each_entry_safe(client, next, &userspace_devices, detected) { + if (client->adapter == adap) { + dev_dbg(&adap->dev, "Removing %s at 0x%x\n", + client->name, client->addr); + list_del(&client->detected); + i2c_unregister_device(client); + } + } + /* Detach any active clients. This can't fail, thus we do not checking the returned value. */ res = device_for_each_child(&adap->dev, NULL, __unregister_client); -- cgit v1.2.3 From 194684e596af4bdaebb424166d94a8aa528edfda Mon Sep 17 00:00:00 2001 From: Mika Kuoppala Date: Sun, 6 Dec 2009 17:06:22 +0100 Subject: i2c: Prevent priority inversion on top of bus lock Low priority thread holding the i2c bus mutex could block higher priority threads to access the bus resulting in unacceptable latencies. Change the mutex type to rt_mutex preventing priority inversion. Tested-by: Peter Ujfalusi Signed-off-by: Mika Kuoppala Signed-off-by: Jean Delvare --- drivers/i2c/i2c-core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/i2c/i2c-core.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 296504355142..d664b4a97a31 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -584,7 +584,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) goto out_list; } - mutex_init(&adap->bus_lock); + rt_mutex_init(&adap->bus_lock); /* Set default timeout to 1 second if not already set */ if (adap->timeout == 0) @@ -1092,12 +1092,12 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) #endif if (in_atomic() || irqs_disabled()) { - ret = mutex_trylock(&adap->bus_lock); + ret = rt_mutex_trylock(&adap->bus_lock); if (!ret) /* I2C activity is ongoing. */ return -EAGAIN; } else { - mutex_lock_nested(&adap->bus_lock, adap->level); + rt_mutex_lock(&adap->bus_lock); } /* Retry automatically on arbitration loss */ @@ -1109,7 +1109,7 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) if (time_after(jiffies, orig_jiffies + adap->timeout)) break; } - mutex_unlock(&adap->bus_lock); + rt_mutex_unlock(&adap->bus_lock); return ret; } else { @@ -1913,7 +1913,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, flags &= I2C_M_TEN | I2C_CLIENT_PEC; if (adapter->algo->smbus_xfer) { - mutex_lock(&adapter->bus_lock); + rt_mutex_lock(&adapter->bus_lock); /* Retry automatically on arbitration loss */ orig_jiffies = jiffies; @@ -1927,7 +1927,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, orig_jiffies + adapter->timeout)) break; } - mutex_unlock(&adapter->bus_lock); + rt_mutex_unlock(&adapter->bus_lock); } else res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write, command, protocol, data); -- cgit v1.2.3 From c7b25a9e96dc89954ae8d8f473f56fae62030f84 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Sun, 6 Dec 2009 17:06:24 +0100 Subject: i2c: Drop probe, ignore and force module parameters The legacy probe and force module parameters are obsolete now, the same can be achieved using the new_device sysfs interface, which is both more flexible and cheaper (it is implemented by i2c-core rather than replicated in every driver module.) The legacy ignore module parameters can be dropped as well. Ignoring can be done by instantiating a "dummy" device at the problematic address. This is the first step of a huge cleanup to i2c-core's i2c_detect function, i2c.h's I2C_CLIENT_INSMOD* macros, and all drivers that made use of them. Signed-off-by: Jean Delvare --- drivers/i2c/i2c-core.c | 65 +------------------------------------------------- 1 file changed, 1 insertion(+), 64 deletions(-) (limited to 'drivers/i2c/i2c-core.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index d664b4a97a31..fdfaebdf3bfe 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1259,40 +1259,13 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) return -ENOMEM; temp_client->adapter = adapter; - /* Force entries are done first, and are not affected by ignore - entries */ - if (address_data->forces) { - const unsigned short * const *forces = address_data->forces; - int kind; - - for (kind = 0; forces[kind]; kind++) { - for (i = 0; forces[kind][i] != I2C_CLIENT_END; - i += 2) { - if (forces[kind][i] == adap_id - || forces[kind][i] == ANY_I2C_BUS) { - dev_dbg(&adapter->dev, "found force " - "parameter for adapter %d, " - "addr 0x%02x, kind %d\n", - adap_id, forces[kind][i + 1], - kind); - temp_client->addr = forces[kind][i + 1]; - err = i2c_detect_address(temp_client, - kind, driver); - if (err) - goto exit_free; - } - } - } - } - /* Stop here if the classes do not match */ if (!(adapter->class & driver->class)) goto exit_free; /* Stop here if we can't use SMBUS_QUICK */ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) { - if (address_data->probe[0] == I2C_CLIENT_END - && address_data->normal_i2c[0] == I2C_CLIENT_END) + if (address_data->normal_i2c[0] == I2C_CLIENT_END) goto exit_free; dev_warn(&adapter->dev, "SMBus Quick command not supported, " @@ -1301,43 +1274,7 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) goto exit_free; } - /* Probe entries are done second, and are not affected by ignore - entries either */ - for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) { - if (address_data->probe[i] == adap_id - || address_data->probe[i] == ANY_I2C_BUS) { - dev_dbg(&adapter->dev, "found probe parameter for " - "adapter %d, addr 0x%02x\n", adap_id, - address_data->probe[i + 1]); - temp_client->addr = address_data->probe[i + 1]; - err = i2c_detect_address(temp_client, -1, driver); - if (err) - goto exit_free; - } - } - - /* Normal entries are done last, unless shadowed by an ignore entry */ for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) { - int j, ignore; - - ignore = 0; - for (j = 0; address_data->ignore[j] != I2C_CLIENT_END; - j += 2) { - if ((address_data->ignore[j] == adap_id || - address_data->ignore[j] == ANY_I2C_BUS) - && address_data->ignore[j + 1] - == address_data->normal_i2c[i]) { - dev_dbg(&adapter->dev, "found ignore " - "parameter for adapter %d, " - "addr 0x%02x\n", adap_id, - address_data->ignore[j + 1]); - ignore = 1; - break; - } - } - if (ignore) - continue; - dev_dbg(&adapter->dev, "found normal entry for adapter %d, " "addr 0x%02x\n", adap_id, address_data->normal_i2c[i]); -- cgit v1.2.3 From ccfbbd082a1c71667bead7124591ccd09f08ac90 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Sun, 6 Dec 2009 17:06:25 +0100 Subject: i2c: Simplify i2c_detect_address The kind parameter of i2c_detect_address() always has value -1, so we can get rid of it. Next step is to update all i2c detect callback functions to get rid of this now useless parameter. Signed-off-by: Jean Delvare --- drivers/i2c/i2c-core.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) (limited to 'drivers/i2c/i2c-core.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index fdfaebdf3bfe..37df0f14c38c 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1180,7 +1180,7 @@ EXPORT_SYMBOL(i2c_master_recv); * ---------------------------------------------------- */ -static int i2c_detect_address(struct i2c_client *temp_client, int kind, +static int i2c_detect_address(struct i2c_client *temp_client, struct i2c_driver *driver) { struct i2c_board_info info; @@ -1199,22 +1199,18 @@ static int i2c_detect_address(struct i2c_client *temp_client, int kind, if (i2c_check_addr(adapter, addr)) return 0; - /* Make sure there is something at this address, unless forced */ - if (kind < 0) { - if (i2c_smbus_xfer(adapter, addr, 0, 0, 0, - I2C_SMBUS_QUICK, NULL) < 0) - return 0; + /* Make sure there is something at this address */ + if (i2c_smbus_xfer(adapter, addr, 0, 0, 0, I2C_SMBUS_QUICK, NULL) < 0) + return 0; - /* prevent 24RF08 corruption */ - if ((addr & ~0x0f) == 0x50) - i2c_smbus_xfer(adapter, addr, 0, 0, 0, - I2C_SMBUS_QUICK, NULL); - } + /* Prevent 24RF08 corruption */ + if ((addr & ~0x0f) == 0x50) + i2c_smbus_xfer(adapter, addr, 0, 0, 0, I2C_SMBUS_QUICK, NULL); /* Finally call the custom detection function */ memset(&info, 0, sizeof(struct i2c_board_info)); info.addr = addr; - err = driver->detect(temp_client, kind, &info); + err = driver->detect(temp_client, -1, &info); if (err) { /* -ENODEV is returned if the detection fails. We catch it here as this isn't an error. */ @@ -1279,7 +1275,7 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) "addr 0x%02x\n", adap_id, address_data->normal_i2c[i]); temp_client->addr = address_data->normal_i2c[i]; - err = i2c_detect_address(temp_client, -1, driver); + err = i2c_detect_address(temp_client, driver); if (err) goto exit_free; } -- cgit v1.2.3 From 69b0089a6750a0435570df3ba8456c77b352af55 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Sun, 6 Dec 2009 17:06:27 +0100 Subject: i2c: Refactor for_each callbacks Functions i2c_do_add_adapter() and __attach_adapter() do essentially the same thing, differing only in how the parameters are passed. Same for i2c_do_add_adapter() and __detach_adapter(). Introduce wrappers to normalize the parameters, so that we do not have to duplicate the code. Signed-off-by: Jean Delvare Cc: David Brownell --- drivers/i2c/i2c-core.c | 70 ++++++++++++++++---------------------------------- 1 file changed, 22 insertions(+), 48 deletions(-) (limited to 'drivers/i2c/i2c-core.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 37df0f14c38c..4f34823e86b1 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -558,11 +558,9 @@ static void i2c_scan_static_board_info(struct i2c_adapter *adapter) up_read(&__i2c_board_lock); } -static int i2c_do_add_adapter(struct device_driver *d, void *data) +static int i2c_do_add_adapter(struct i2c_driver *driver, + struct i2c_adapter *adap) { - struct i2c_driver *driver = to_i2c_driver(d); - struct i2c_adapter *adap = data; - /* Detect supported devices on that bus, and instantiate them */ i2c_detect(adap, driver); @@ -574,6 +572,11 @@ static int i2c_do_add_adapter(struct device_driver *d, void *data) return 0; } +static int __process_new_adapter(struct device_driver *d, void *data) +{ + return i2c_do_add_adapter(to_i2c_driver(d), data); +} + static int i2c_register_adapter(struct i2c_adapter *adap) { int res = 0, dummy; @@ -614,7 +617,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) /* Notify drivers */ mutex_lock(&core_lock); dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap, - i2c_do_add_adapter); + __process_new_adapter); mutex_unlock(&core_lock); return 0; @@ -715,10 +718,9 @@ retry: } EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); -static int i2c_do_del_adapter(struct device_driver *d, void *data) +static int i2c_do_del_adapter(struct i2c_driver *driver, + struct i2c_adapter *adapter) { - struct i2c_driver *driver = to_i2c_driver(d); - struct i2c_adapter *adapter = data; struct i2c_client *client, *_n; int res; @@ -750,6 +752,11 @@ static int __unregister_client(struct device *dev, void *dummy) return 0; } +static int __process_removed_adapter(struct device_driver *d, void *data) +{ + return i2c_do_del_adapter(to_i2c_driver(d), data); +} + /** * i2c_del_adapter - unregister I2C adapter * @adap: the adapter being unregistered @@ -777,7 +784,7 @@ int i2c_del_adapter(struct i2c_adapter *adap) /* Tell drivers about this removal */ mutex_lock(&core_lock); res = bus_for_each_drv(&i2c_bus_type, NULL, adap, - i2c_do_del_adapter); + __process_removed_adapter); mutex_unlock(&core_lock); if (res) return res; @@ -826,22 +833,11 @@ EXPORT_SYMBOL(i2c_del_adapter); /* ------------------------------------------------------------------------- */ -static int __attach_adapter(struct device *dev, void *data) +static int __process_new_driver(struct device *dev, void *data) { - struct i2c_adapter *adapter; - struct i2c_driver *driver = data; - if (dev->type != &i2c_adapter_type) return 0; - adapter = to_i2c_adapter(dev); - - i2c_detect(adapter, driver); - - /* Legacy drivers scan i2c busses directly */ - if (driver->attach_adapter) - driver->attach_adapter(adapter); - - return 0; + return i2c_do_add_adapter(data, to_i2c_adapter(dev)); } /* @@ -873,40 +869,18 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver) INIT_LIST_HEAD(&driver->clients); /* Walk the adapters that are already present */ mutex_lock(&core_lock); - bus_for_each_dev(&i2c_bus_type, NULL, driver, __attach_adapter); + bus_for_each_dev(&i2c_bus_type, NULL, driver, __process_new_driver); mutex_unlock(&core_lock); return 0; } EXPORT_SYMBOL(i2c_register_driver); -static int __detach_adapter(struct device *dev, void *data) +static int __process_removed_driver(struct device *dev, void *data) { - struct i2c_adapter *adapter; - struct i2c_driver *driver = data; - struct i2c_client *client, *_n; - if (dev->type != &i2c_adapter_type) return 0; - adapter = to_i2c_adapter(dev); - - /* Remove the devices we created ourselves as the result of hardware - * probing (using a driver's detect method) */ - list_for_each_entry_safe(client, _n, &driver->clients, detected) { - dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", - client->name, client->addr); - list_del(&client->detected); - i2c_unregister_device(client); - } - - if (driver->detach_adapter) { - if (driver->detach_adapter(adapter)) - dev_err(&adapter->dev, - "detach_adapter failed for driver [%s]\n", - driver->driver.name); - } - - return 0; + return i2c_do_del_adapter(data, to_i2c_adapter(dev)); } /** @@ -917,7 +891,7 @@ static int __detach_adapter(struct device *dev, void *data) void i2c_del_driver(struct i2c_driver *driver) { mutex_lock(&core_lock); - bus_for_each_dev(&i2c_bus_type, NULL, driver, __detach_adapter); + bus_for_each_dev(&i2c_bus_type, NULL, driver, __process_removed_driver); mutex_unlock(&core_lock); driver_unregister(&driver->driver); -- cgit v1.2.3