From: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Date: Wed, 19 May 2010 15:41:13 +0000 (-0400)
Subject: Allocate buffer when opening and added release function.
X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fkernel%2Fsamples%2Fchar2%2F.git;a=commitdiff_plain;h=d99e8889b3f62defbf49d6a3d407abcc9d2a6d6f

Allocate buffer when opening and added release function.
---

diff --git a/hellochar.c b/hellochar.c
index e49565c..c95100e 100644
--- a/hellochar.c
+++ b/hellochar.c
@@ -25,10 +25,19 @@ MODULE_LICENSE("GPL");
 
 static dev_t devnum;
 static struct cdev *dev;
+static const char default_greeting[] = "Hello, World!\n";
+
+struct hello_buffer {
+	size_t len;
+	char buffer[0];
+};
 
 static int hello_open(struct inode *ino, struct file *fp)
 {
-	printk(KERN_DEBUG "Hello, World!\n");
+	struct hello_buffer *hello = kmalloc(sizeof(*hello) + 4000, GFP_KERNEL);
+	if (!hello)
+		return -ENOMEM;
+	hello->private_data = hello;
 	return 0;
 }
 
@@ -38,9 +47,16 @@ static ssize_t hello_read(struct file *fp, char __user *buf, size_t sz,
 	return 0;
 }
 
+static int hello_release(struct inode *ino, struct file *fp)
+{
+	kfree(fp->private_data);
+	return 0;
+}
+
 static const struct file_operations hello_fops = {
 	.owner = THIS_MODULE,
 	.open = hello_open,
+	.release = hello_release,
 	.read = hello_read,
 };