crypto: qat - change behaviour of adf_cfg_add_key_value_param()

The function adf_cfg_add_key_value_param() allows to insert duplicates
entries in the key value store of the driver.

Change the behaviour of that function to the following policy:
- if the key doesn't exist, add it;
- if the key already exists with a different value, then delete it and
  replace it with a new one containing the new value;
- if the key exists with the same value, then return without doing
  anything.

The behaviour of this function has been changed in order to easily
update key-values in the driver database. In particular this is required
to update the value of the ServiceEnables key used to change the service
loaded on a device.

Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Adam Guerin <adam.guerin@intel.com>
Reviewed-by: Fiona Trahe <fiona.trahe@intel.com>
Reviewed-by: Wojciech Ziemba <wojciech.ziemba@intel.com>
Reviewed-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Author: gcabiddu

drivers/crypto/qat/qat_common/adf_cfg.c

@@ -128,6 +128,24 @@ static void adf_cfg_keyval_add(struct adf_cfg_key_val *new,
 	list_add_tail(&new->list, &sec->param_head);
 }
 
+static void adf_cfg_keyval_remove(const char *key, struct adf_cfg_section *sec)
+{
+	struct list_head *head = &sec->param_head;
+	struct list_head *list_ptr, *tmp;
+
+	list_for_each_prev_safe(list_ptr, tmp, head) {
+		struct adf_cfg_key_val *ptr =
+			list_entry(list_ptr, struct adf_cfg_key_val, list);
+
+		if (strncmp(ptr->key, key, sizeof(ptr->key)))
+			continue;
+
+		list_del(list_ptr);
+		kfree(ptr);
+		break;
+	}
+}
+
 static void adf_cfg_keyval_del_all(struct list_head *head)
 {
 	struct list_head *list_ptr, *tmp;
@@ -208,7 +226,8 @@ static int adf_cfg_key_val_get(struct adf_accel_dev *accel_dev,
  * @type: Type - string, int or address
  *
  * Function adds configuration key - value entry in the appropriate section
- * in the given acceleration device
+ * in the given acceleration device. If the key exists already, the value
+ * is updated.
  * To be used by QAT device specific drivers.
  *
  * Return: 0 on success, error code otherwise.
@@ -222,6 +241,8 @@ int adf_cfg_add_key_value_param(struct adf_accel_dev *accel_dev,
 	struct adf_cfg_key_val *key_val;
 	struct adf_cfg_section *section = adf_cfg_sec_find(accel_dev,
 							   section_name);
+	char temp_val[ADF_CFG_MAX_VAL_LEN_IN_BYTES];
+
 	if (!section)
 		return -EFAULT;
 
@@ -246,6 +267,24 @@ int adf_cfg_add_key_value_param(struct adf_accel_dev *accel_dev,
 		return -EINVAL;
 	}
 	key_val->type = type;
+
+	/* Add the key-value pair as below policy:
+	 * 1. if the key doesn't exist, add it;
+	 * 2. if the key already exists with a different value then update it
+	 *    to the new value (the key is deleted and the newly created
+	 *    key_val containing the new value is added to the database);
+	 * 3. if the key exists with the same value, then return without doing
+	 *    anything (the newly created key_val is freed).
+	 */
+	if (!adf_cfg_key_val_get(accel_dev, section_name, key, temp_val)) {
+		if (strncmp(temp_val, key_val->val, sizeof(temp_val))) {
+			adf_cfg_keyval_remove(key, section);
+		} else {
+			kfree(key_val);
+			return 0;
+		}
+	}
+
 	down_write(&cfg->lock);
 	adf_cfg_keyval_add(key_val, section);
 	up_write(&cfg->lock);