added task1 implementation

tasks/linked_lists/module.c

@@ -13,7 +13,7 @@ static void __init test_stack(void)
     stack_entry_t *tos = NULL;
     const char *tos_data = NULL;
     const char* test_data[] = { "1", "2", "3", "4" };
-    unsigned long i = 0;
+    long i = 0;
 
     pr_alert("Testing basic stack");
 
@@ -36,7 +36,25 @@ static void __init test_stack(void)
 
 static void __init print_processes_backwards(void)
 {
-    // TODO
+    struct task_struct *task_list;
+    LIST_HEAD(proc_stack);
+    long counter = 0;
+    const char *process_name = NULL;
+    stack_entry_t *stack_top = NULL;
+
+	for_each_process(task_list) 
+	{
+		stack_push(&proc_stack, create_stack_entry((void*)(task_list->comm)));
+		counter++;
+	}
+
+	for (; counter > 0; counter--)
+	{
+		stack_top = stack_pop(&proc_stack);
+		process_name = STACK_ENTRY_DATA(stack_top, const char*);
+		printk(KERN_ALERT "%s\n", process_name);
+	}
+
 }
 
 static int __init ll_init(void)

tasks/linked_lists/stack.c

@@ -1,28 +1,33 @@
+#include <linux/slab.h>
 #include "stack.h"
 
 stack_entry_t* create_stack_entry(void *data)
 {
-    // TODO
-    (void)data;
-    return NULL;
+    stack_entry_t *entry = kmalloc(sizeof(stack_entry_t), GFP_KERNEL);
+    if (!entry)
+    	return 0;
+    entry->data = data;
+    return entry;
 }
 
 void delete_stack_entry(stack_entry_t *entry)
 {
-    // TODO
-    (void)entry;
+    kfree(entry);
 }
 
 void stack_push(struct list_head *stack, stack_entry_t *entry)
 {
-    // TODO
-    (void)stack;
-    (void)entry;
+    list_add(&(entry->lh), stack);
 }
 
 stack_entry_t* stack_pop(struct list_head *stack)
 {
-    // TODO
-    (void)stack;
-    return NULL;
+	struct list_head *ret_val = stack->next;
+
+	if (stack_empty(stack))
+		return 0;
+
+    list_del_init(ret_val);
+
+    return list_entry(ret_val, struct stack_entry, lh);
 }