From: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Date: Wed, 19 May 2010 16:15:38 +0000 (-0400)
Subject: Use global buffer.
X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fkernel%2Fsamples%2Fchar2%2F.git;a=commitdiff_plain;h=a7653a054c66dd1a3bb9a63288c875fa428559f0

Use global buffer.
---

diff --git a/hellochar.c b/hellochar.c
index 1649fe3..ee09b1e 100644
--- a/hellochar.c
+++ b/hellochar.c
@@ -33,22 +33,16 @@ struct hello_buffer {
 	size_t len;
 	char buffer[0];
 };
+struct hello_buffer *hello;
 
 static int hello_open(struct inode *ino, struct file *fp)
 {
-	struct hello_buffer *hello = kzalloc(sizeof(*hello) + MAXLEN, GFP_KERNEL);
-	if (!hello)
-		return -ENOMEM;
-	memcpy(hello->buffer, default_greeting, sizeof(default_greeting));
-	hello->len = sizeof(default_greeting);
-	fp->private_data = hello;
 	return 0;
 }
 
 static ssize_t hello_read(struct file *fp, char __user *buf, size_t sz,
 	loff_t *pos)
 {
-	struct hello_buffer *hello = fp->private_data;
 	int r;
 	if (sz + *pos > hello->len)
 		sz = hello->len - *pos;
@@ -62,7 +56,6 @@ static ssize_t hello_read(struct file *fp, char __user *buf, size_t sz,
 static ssize_t hello_write(struct file *fp, const char __user *buf, size_t sz,
 	loff_t *pos)
 {
-	struct hello_buffer *hello = fp->private_data;
 	int r;
 	if (sz + *pos > MAXLEN)
 		sz = MAXLEN - *pos;
@@ -77,7 +70,6 @@ static ssize_t hello_write(struct file *fp, const char __user *buf, size_t sz,
 
 static int hello_release(struct inode *ino, struct file *fp)
 {
-	kfree(fp->private_data);
 	return 0;
 }
 
@@ -92,9 +84,16 @@ static const struct file_operations hello_fops = {
 static int __init ch_init(void)
 {
 	int r = 0;
+	hello = kzalloc(sizeof(*hello) + MAXLEN, GFP_KERNEL);
+	if (!hello) {
+		r = -ENOMEM;
+		goto out;
+	}
+	memcpy(hello->buffer, default_greeting, sizeof(default_greeting));
+	hello->len = sizeof(default_greeting);
 	r = alloc_chrdev_region(&devnum, 0, 256, "hello");
 	if (r)
-		goto out;
+		goto reg_out;
 	dev = cdev_alloc();
 	if (!dev) {
 		r = -ENOMEM;
@@ -110,6 +109,8 @@ add_out:
 	kfree(dev);
 cdev_out:
 	unregister_chrdev_region(devnum, 256);
+reg_out:
+	kfree(hello);
 out:
 	return r;
 }
@@ -118,6 +119,7 @@ static void __exit ch_exit(void)
 {
 	cdev_del(dev);
 	unregister_chrdev_region(devnum, 256);
+	kfree(hello);
 }
 
 module_init(ch_init);