lkml.org 
[lkml]   [2009]   [Oct]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 03/28] net: Remove BKL from tun
The lock_kernel/unlock_kernel() in cycle_kernel_lock() which is called
in tun_chr_open() is not serializing against anything and safe to
remove.

tun_chr_fasync() is serialized by get/put_tun() and fasync_helper()
has no dependency on BKL. The modification of tun->flags is racy with
and without the BKL so removing it does not make it worse.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David S. Miller <davem@davemloft.net>

---
drivers/net/tun.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

Index: linux-2.6-tip/drivers/net/tun.c
===================================================================
--- linux-2.6-tip.orig/drivers/net/tun.c
+++ linux-2.6-tip/drivers/net/tun.c
@@ -44,7 +44,6 @@
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
#include <linux/init.h>
@@ -1285,7 +1284,6 @@ static int tun_chr_fasync(int fd, struct

DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);

- lock_kernel();
if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
goto out;

@@ -1298,7 +1296,6 @@ static int tun_chr_fasync(int fd, struct
tun->flags &= ~TUN_FASYNC;
ret = 0;
out:
- unlock_kernel();
tun_put(tun);
return ret;
}
@@ -1306,7 +1303,7 @@ out:
static int tun_chr_open(struct inode *inode, struct file * file)
{
struct tun_file *tfile;
- cycle_kernel_lock();
+
DBG1(KERN_INFO "tunX: tun_chr_open\n");

tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);



\
 
 \ /
  Last update: 2009-10-10 18:15    [W:0.375 / U:10.952 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site