added locking for queue

LRU.c

@@ -16,15 +16,17 @@
 struct KV *array[MAX_SIZE];
 struct queue *qu=NULL;
 struct queue *last;
-
-
+unsigned _Atomic lock;
 
 
 void remove_element_from_deque(char *key)
 {
+    while(ATOMIC_TEST_AND_SET(&(lock),1) == 1);
     queue *present = qu , *previous=NULL;
-    if(present == NULL)
+    if(present == NULL){
+        CLEAR(&(lock),0);
         return;
+    }
     
     if(strcmp(present->key, key) == 0)
     {
@@ -32,6 +34,7 @@ void remove_element_from_deque(char *key)
         if(last == present)
             last = last->next;
         free(present);
+        CLEAR(&(lock),0);
         return;
     }
 
@@ -43,15 +46,18 @@ void remove_element_from_deque(char *key)
                 last = previous;
             previous->next = present->next;
             free(present);
+            CLEAR(&(lock),0);
             return;
         }
         previous = present;
         present = present->next;
     }
+    CLEAR(&(lock),0);
 }
 
 void insert_into_queue(char *key)
 {
+    while(ATOMIC_TEST_AND_SET(&(lock),1) == 1);
     queue *temp = (queue *)malloc(sizeof(queue));
     memcpy(temp->key, key, KEY_SIZE);
     temp->next = NULL;
@@ -65,6 +71,7 @@ void insert_into_queue(char *key)
         last->next = temp;
         last = temp;
     }
+    CLEAR(&(lock),0);
 }
 
 int remove_front_element()
@@ -79,6 +86,7 @@ int remove_front_element()
         {
             // check if it is modified to write to file
             array[i]->valid = FALSE;
+            CLEAR(&(lock),0);
             return i;
         }
     }
@@ -86,12 +94,18 @@ int remove_front_element()
 
 int find_empty_location()
 {
+    while(ATOMIC_TEST_AND_SET(&(lock),1) == 1);
     for(int i=0;i<MAX_SIZE;i++)
     {
         if(array[i]->valid == FALSE)
+        {
+            CLEAR(&(lock),0);
             return i;
+        }
     }
-    return remove_front_element();
+    int indx = remove_front_element();
+    CLEAR(&(lock),0);
+    return indx;
 }
 
 int cache_del(char *key)