Moving few variables out of global scope and adding -Wall

Makefile

@@ -23,6 +23,8 @@
 
 SHELL:=/bin/bash
 
+ccflags-y := -Wall
+
 obj-m += lkm_device.o lkm_parameters.o lkm_proc.o lkm_sandbox.o lkm_skeleton.o
 
 all:

lkm_device.c

@@ -59,11 +59,11 @@ static int device_open_count = 0;
 static char message_buffer[MESSAGE_BUFFER_LENGTH];
 static char *message_ptr;
 
-static struct file_operations device_fops = { .open = device_open,
+static struct file_operations device_fops = { .owner = THIS_MODULE,
+					      .open = device_open,
 					      .read = device_read,
 					      .release = device_release,
 					      .write = device_write };
-struct proc_dir_entry *proc_major_entry;
 
 module_param(param_major_num, int, PARAM_MAJOR_NUM_PERMISSION);
 
@@ -182,13 +182,16 @@ static int device_init_sub(void)
 
 static int proc_init_sub(void)
 {
+	struct proc_dir_entry *proc_major_entry = NULL;
+
 	printk(KERN_INFO
 	       "lkm_device: Registered sandbox device with major number %d.\n",
 	       major_num);
 
 	printk(KERN_INFO
 	       "lkm_device: Creating /proc file %s for storing major number %d.\n",
 	       PROC_FILE_NAME, major_num);
+
 	proc_major_entry = proc_create_single(PROC_FILE_NAME, PROC_PERMISSION,
 					      PROC_PARENT, proc_show);
 

lkm_proc.c

@@ -39,13 +39,14 @@ static int lkm_proc_show(struct seq_file *seq, void *v);
 #define LKM_PROC_PARENT NULL // root of /proc
 #define LKM_PROC_PERMISSION 0444
 
-struct proc_dir_entry *lkm_proc_entry;
-
 static int __init lkm_proc_init(void)
 {
+	struct proc_dir_entry *lkm_proc_entry = NULL;
+
 	printk(KERN_INFO
 	       "lkm_proc: Initializing module for accessing /proc/%s.\n",
 	       LKM_PROC_FILE_NAME);
+
 	lkm_proc_entry =
 		proc_create_single(LKM_PROC_FILE_NAME, LKM_PROC_PERMISSION,
 				   LKM_PROC_PARENT, lkm_proc_show);
@@ -61,8 +62,7 @@ static int __init lkm_proc_init(void)
 
 static void __exit lkm_proc_exit(void)
 {
-	printk(KERN_INFO "lkm_proc: Removing /proc/%s.\n",
-	       LKM_PROC_FILE_NAME);
+	printk(KERN_INFO "lkm_proc: Removing /proc/%s.\n", LKM_PROC_FILE_NAME);
 
 	remove_proc_entry(LKM_PROC_FILE_NAME, LKM_PROC_PARENT);
 }