| Date | Sat, 10 Oct 2009 15:35:33 -0000 | From | Thomas Gleixner <> | Subject | [patch 03/28] net: Remove BKL from tun |
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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);
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