[PATCH] I2C: keep i2c-dev numbers in sync with i2c adapter numbers

This makes userspace tools easier to figure out which i2c-dev device is
assigned to which i2c adapter.

Yes, we can overflow the i2c dev array right now, but that would take a
lot of i2c adapter modprobe/rmmod cycles.  That will be fixed up soon.

drivers/i2c/i2c-dev.c

@@ -72,24 +72,18 @@ struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
 struct i2c_dev *i2c_dev_get_by_adapter(struct i2c_adapter *adap)
 {
 	struct i2c_dev *i2c_dev = NULL;
-	int i;
 
 	spin_lock(&i2c_dev_array_lock);
-	for (i = 0; i < I2C_MINORS; ++i) {
-		if ((i2c_dev_array[i]) &&
-		    (i2c_dev_array[i]->adap == adap)) {
-			i2c_dev = i2c_dev_array[i];
-			break;
-		}
-	}
+	if ((i2c_dev_array[adap->nr]) &&
+	    (i2c_dev_array[adap->nr]->adap == adap))
+		i2c_dev = i2c_dev_array[adap->nr];
 	spin_unlock(&i2c_dev_array_lock);
 	return i2c_dev;
 }
 
-static struct i2c_dev *get_free_i2c_dev(void)
+static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
 {
 	struct i2c_dev *i2c_dev;
-	unsigned int i;
 
 	i2c_dev = kmalloc(sizeof(*i2c_dev), GFP_KERNEL);
 	if (!i2c_dev)
@@ -97,15 +91,16 @@ static struct i2c_dev *get_free_i2c_dev(void)
 	memset(i2c_dev, 0x00, sizeof(*i2c_dev));
 
 	spin_lock(&i2c_dev_array_lock);
-	for (i = 0; i < I2C_MINORS; ++i) {
-		if (i2c_dev_array[i])
-			continue;
-		i2c_dev->minor = i;
-		i2c_dev_array[i] = i2c_dev;
+	if (i2c_dev_array[adap->nr]) {
 		spin_unlock(&i2c_dev_array_lock);
-		return i2c_dev;
+		dev_err(&adap->dev, "i2c-dev already has a device assigned to this adapter\n");
+		goto error;
 	}
+	i2c_dev->minor = adap->nr;
+	i2c_dev_array[adap->nr] = i2c_dev;
 	spin_unlock(&i2c_dev_array_lock);
+	return i2c_dev;
+error:
 	kfree(i2c_dev);
 	return ERR_PTR(-ENODEV);
 }
@@ -446,7 +441,7 @@ static int i2cdev_attach_adapter(struct i2c_adapter *adap)
 	struct i2c_dev *i2c_dev;
 	int retval;
 
-	i2c_dev = get_free_i2c_dev();
+	i2c_dev = get_free_i2c_dev(adap);
 	if (IS_ERR(i2c_dev))
 		return PTR_ERR(i2c_dev);