i2c: Optimize function i2c_detect()

Check the class flags before allocating the temporary i2c_client
structure, to avoid allocating it when we don't need it.

Also optimize the inner loop a bit.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index bdadfaf3fe10..d231f683f576 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1508,26 +1508,25 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
         if (!driver->detect || !address_list)
                 return 0;
 
+        /* Stop here if the classes do not match */
+        if (!(adapter->class & driver->class))
+                return 0;
+
         /* Set up a temporary client to help detect callback */
         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
         if (!temp_client)
                 return -ENOMEM;
         temp_client->adapter = adapter;
 
-        /* Stop here if the classes do not match */
-        if (!(adapter->class & driver->class))
-                goto exit_free;
-
         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
                 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
                         "addr 0x%02x\n", adap_id, address_list[i]);
                 temp_client->addr = address_list[i];
                 err = i2c_detect_address(temp_client, driver);
-                if (err)
-                        goto exit_free;
+                if (unlikely(err))
+                        break;
         }
 
- exit_free:
         kfree(temp_client);
         return err;
 }