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i2c: Use a separate mutex for userspace client lists

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Moving userspace-instantiated clients to separate lists wasn't nearly
enough to avoid deadlocks in multiplexed bus cases. We also want to
have a dedicated mutex to protect each list.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Michael Lawnick <ml.lawnick@gmx.de>
This commit is contained in:
Jean Delvare 2010-08-11 18:21:01 +02:00
parent 8031d79bae
commit dafc50d141
2 changed files with 8 additions and 6 deletions
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13
drivers/i2c/i2c-core.c
View File

@ -662,9 +662,9 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
return -EINVAL;
/* Keep track of the added device */
i2c_lock_adapter(adap);
mutex_lock(&adap->userspace_clients_lock);
list_add_tail(&client->detected, &adap->userspace_clients);
i2c_unlock_adapter(adap);
mutex_unlock(&adap->userspace_clients_lock);
dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
info.type, info.addr);
@ -703,7 +703,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
/* Make sure the device was added through sysfs */
res = -ENOENT;
i2c_lock_adapter(adap);
mutex_lock(&adap->userspace_clients_lock);
list_for_each_entry_safe(client, next, &adap->userspace_clients,
detected) {
if (client->addr == addr) {
@ -716,7 +716,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
break;
}
}
i2c_unlock_adapter(adap);
mutex_unlock(&adap->userspace_clients_lock);
if (res < 0)
dev_err(dev, "%s: Can't find device in list\n",
@ -798,6 +798,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
}
rt_mutex_init(&adap->bus_lock);
mutex_init(&adap->userspace_clients_lock);
INIT_LIST_HEAD(&adap->userspace_clients);
/* Set default timeout to 1 second if not already set */
@ -1003,7 +1004,7 @@ int i2c_del_adapter(struct i2c_adapter *adap)
return res;
/* Remove devices instantiated from sysfs */
i2c_lock_adapter(adap);
mutex_lock(&adap->userspace_clients_lock);
list_for_each_entry_safe(client, next, &adap->userspace_clients,
detected) {
dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
@ -1011,7 +1012,7 @@ int i2c_del_adapter(struct i2c_adapter *adap)
list_del(&client->detected);
i2c_unregister_device(client);
}
i2c_unlock_adapter(adap);
mutex_unlock(&adap->userspace_clients_lock);
/* Detach any active clients. This can't fail, thus we do not
checking the returned value. */

1
include/linux/i2c.h
View File

@ -368,6 +368,7 @@ struct i2c_adapter {
char name[48];
struct completion dev_released;
struct mutex userspace_clients_lock;
struct list_head userspace_clients;
};
#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)