[PATCH] TUN/TAP driver readv/writev support 2.4.19-pre7

[Maksim]

Marcelo,

This patch adds proper support for readv/writev support in 
TUN/TAP driver.
http://bluez.sourceforge.net/patches/tun-readv-writev-2.4.19-pre7.gz

Pleas apply

Thanks
Max

diff -urN /opt/kernel/linux/drivers/net/tun.c linux/drivers/net/tun.c
--- /opt/kernel/linux/drivers/net/tun.c	Mon Jan  7 15:41:41 2002
+++ linux/drivers/net/tun.c	Mon Apr 22 17:38:08 2002
@@ -1,6 +1,6 @@
 /*
  *  TUN - Universal TUN/TAP device driver.
- *  Copyright (C) 1999-2000 Maxim Krasnyansky <[e-mail]>
+ *  Copyright (C) 1999-2002 Maxim Krasnyansky <[e-mail]>
*
  *  This program is free software; you can redistribute it and/or
modify
  *  it under the terms of the GNU General Public License as published
by
@@ -12,7 +12,7 @@
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  *  GNU General Public License for more details.
  *
- *  $Id: tun.c,v 1.12 2001/03/08 03:29:27 maxk Exp $
+ *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
  */
 
 /*
@@ -20,7 +20,7 @@
  *    Modifications for 2.3.99-pre5 kernel.
  */
 
-#define TUN_VER "1.4"
+#define TUN_VER "1.5"
 
 #include <linux/config.h>
#include <linux/module.h>
@@ -181,19 +181,17 @@
 }
 
 /* Get packet from user space buffer(already verified) */
-static __inline__ ssize_t tun_get_user(struct tun_struct *tun, const
char *buf, size_t count)
+static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct
iovec *iv, size_t count)
 {
 	struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
-	register const char *ptr = buf; 
-	register int len = count;
 	struct sk_buff *skb;
+	size_t len = count;
 
 	if (!(tun->flags & TUN_NO_PI)) {
 		if ((len -= sizeof(pi)) < 0)
 			return -EINVAL;
 
-		copy_from_user(&pi, ptr, sizeof(pi));
-		ptr += sizeof(pi);
+		memcpy_fromiovec((void *)&pi, iv, sizeof(pi));
 	}
  
 	if (!(skb = alloc_skb(len + 2, GFP_KERNEL))) {
@@ -202,7 +200,7 @@
 	}
 
 	skb_reserve(skb, 2);
-	copy_from_user(skb_put(skb, len), ptr, len); 
+	memcpy_fromiovec(skb_put(skb, len), iv, len);
 
 	skb->dev = &tun->dev;
 	switch (tun->flags & TUN_TYPE_MASK) {
@@ -226,31 +224,43 @@
 	return count;
 } 
 
-/* Write */
-static ssize_t tun_chr_write(struct file * file, const char * buf, 
-			     size_t count, loff_t *pos)
+/* Writev */
+static ssize_t tun_chr_writev(struct file * file, const struct iovec
*iv, 
+			      unsigned long count, loff_t *pos)
 {
 	struct tun_struct *tun = (struct tun_struct *)file->private_data;
+	unsigned long i;
+	size_t len;
 
 	if (!tun)
 		return -EBADFD;
 
 	DBG(KERN_INFO "%s: tun_chr_write %d\n", tun->name, count);
 
-	if (verify_area(VERIFY_READ, buf, count))
-		return -EFAULT;
+	for (i = 0, len = 0; i < count; i++) {
+		if (verify_area(VERIFY_READ, iv[i].iov_base, iv[i].iov_len))
+			return -EFAULT;
+		len += iv[i].iov_len;
+	}
 
-	return tun_get_user(tun, buf, count);
+	return tun_get_user(tun, (struct iovec *) iv, len);
 }
 
-/* Put packet to user space buffer(already verified) */
+/* Write */
+static ssize_t tun_chr_write(struct file * file, const char * buf, 
+			     size_t count, loff_t *pos)
+{
+	struct iovec iv = { (void *) buf, count };
+	return tun_chr_writev(file, &iv, 1, pos);
+}
+
+/* Put packet to the user space buffer (already verified) */
 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 				       struct sk_buff *skb,
-				       char *buf, int count)
+				       struct iovec *iv, int len)
 {
 	struct tun_pi pi = { 0, skb->protocol };
-	int len = count, total = 0;
-	char *ptr = buf;
+	ssize_t total = 0;
 
 	if (!(tun->flags & TUN_NO_PI)) {
 		if ((len -= sizeof(pi)) < 0)
@@ -261,14 +271,13 @@
 			pi.flags |= TUN_PKT_STRIP;
 		}
  
-		copy_to_user(ptr, &pi, sizeof(pi));
-
+		memcpy_toiovec(iv, (void *) &pi, sizeof(pi));
 		total += sizeof(pi);
-		ptr += sizeof(pi);
 	}       
 
-	len = MIN(skb->len, len); 
-	copy_to_user(ptr, skb->data, len); 
+	len = MIN(skb->len, len);
+
+	skb_copy_datagram_iovec(skb, 0, iv, len);
 	total += len;
 
 	tun->stats.tx_packets++;
@@ -277,22 +286,29 @@
 	return total;
 }
 
-/* Read */
-static ssize_t tun_chr_read(struct file * file, char * buf, 
-			    size_t count, loff_t *pos)
+/* Readv */
+static ssize_t tun_chr_readv(struct file *file, const struct iovec *iv,
+			    unsigned long count, loff_t *pos)
 {
 	struct tun_struct *tun = (struct tun_struct *)file->private_data;
 	DECLARE_WAITQUEUE(wait, current);
 	struct sk_buff *skb;
-	ssize_t ret = 0;
+	ssize_t len, ret = 0;
+	unsigned long i;
 
 	if (!tun)
 		return -EBADFD;
 
 	DBG(KERN_INFO "%s: tun_chr_read\n", tun->name);
 
+	for (i = 0, len = 0; i < count; i++) {
+		if (verify_area(VERIFY_WRITE, iv[i].iov_base, iv[i].iov_len))
+			return -EFAULT;
+		len += iv[i].iov_len;
+	}
+
 	add_wait_queue(&tun->read_wait, &wait);
-	while (count) {
+	while (len) {
 		current->state = TASK_INTERRUPTIBLE;
 
 		/* Read frames from the queue */
@@ -312,10 +328,7 @@
 		}
 		netif_start_queue(&tun->dev);
 
-		if (!verify_area(VERIFY_WRITE, buf, count))
-			ret = tun_put_user(tun, skb, buf, count);
-		else
-			ret = -EFAULT;
+		ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 
 		kfree_skb(skb);
 		break;
@@ -327,6 +340,14 @@
 	return ret;
 }
 
+/* Read */
+static ssize_t tun_chr_read(struct file * file, char * buf, 
+			    size_t count, loff_t *pos)
+{
+	struct iovec iv = { buf, count };
+	return tun_chr_readv(file, &iv, 1, pos);
+}
+
 static int tun_set_iff(struct file *file, struct ifreq *ifr)
 {
 	struct tun_struct *tun;
@@ -546,7 +567,9 @@
 	owner:	THIS_MODULE,	
 	llseek:	no_llseek,
 	read:	tun_chr_read,
+	readv:	tun_chr_readv,
 	write:	tun_chr_write,
+	writev:	tun_chr_writev,
 	poll:	tun_chr_poll,
 	ioctl:	tun_chr_ioctl,
 	open:	tun_chr_open,
@@ -564,7 +587,7 @@
 int __init tun_init(void)
 {
 	printk(KERN_INFO "Universal TUN/TAP device driver %s " 
-	       "(C)1999-2001 Maxim Krasnyansky\n", TUN_VER);
+	       "(C)1999-2002 Maxim Krasnyansky\n", TUN_VER);
 
 	if (misc_register(&tun_miscdev)) {
 		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);