[PATCH] i2c: Prevent deadlock on i2c client registration
Delay the call to adapter->client_register() until after we are
certain that the client registration is a success. At this point the
client is fully initialized and we no longer hold the adapter->clist
mutex, so this should prevent the deadlocks if the client_register()
callback needs to take that mutex too, as is the case for the bttv
driver.
This fixes bug #7234.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 01233f0..7ca81f4 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -420,14 +420,6 @@
}
list_add_tail(&client->list,&adapter->clients);
- if (adapter->client_register) {
- if (adapter->client_register(client)) {
- dev_dbg(&adapter->dev, "client_register "
- "failed for client [%s] at 0x%02x\n",
- client->name, client->addr);
- }
- }
-
client->usage_count = 0;
client->dev.parent = &client->adapter->dev;
@@ -445,10 +437,17 @@
res = device_create_file(&client->dev, &dev_attr_client_name);
if (res)
goto out_unregister;
-
-out_unlock:
mutex_unlock(&adapter->clist_lock);
- return res;
+
+ if (adapter->client_register) {
+ if (adapter->client_register(client)) {
+ dev_dbg(&adapter->dev, "client_register "
+ "failed for client [%s] at 0x%02x\n",
+ client->name, client->addr);
+ }
+ }
+
+ return 0;
out_unregister:
init_completion(&client->released); /* Needed? */
@@ -458,7 +457,9 @@
list_del(&client->list);
dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x "
"(%d)\n", client->name, client->addr, res);
- goto out_unlock;
+out_unlock:
+ mutex_unlock(&adapter->clist_lock);
+ return res;
}