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>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 4fdfa2a..9c59a82 100644
--- a/drivers/net/tun.c
+++ b/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 @@
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 @@
tun->flags &= ~TUN_FASYNC;
ret = 0;
out:
- unlock_kernel();
tun_put(tun);
return ret;
}
@@ -1306,7 +1303,7 @@
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);