i2c: Use a separate mutex for userspace client lists
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>
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index ba86af6..97f96b6 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -662,9 +662,9 @@
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 @@
/* 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 @@
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 @@
}
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 @@
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 @@
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. */