aboutsummaryrefslogtreecommitdiff
path: root/fs/ioctl.c
diff options
context:
space:
mode:
authorJonathan Corbet <corbet@lwn.net>2009-02-06 15:25:24 -0700
committerJonathan Corbet <corbet@lwn.net>2009-03-16 08:32:27 -0600
commitdb1dd4d376134eba0e08af523b61cc566a4ea1cd (patch)
tree8882c673abbaa5713511b7046493fa862b9140d1 /fs/ioctl.c
parent684999149002dd046269666a390458e0acb38280 (diff)
downloadlinux-db1dd4d376134eba0e08af523b61cc566a4ea1cd.tar.gz
Use f_lock to protect f_flags
Traditionally, changes to struct file->f_flags have been done under BKL protection, or with no protection at all. This patch causes all f_flags changes after file open/creation time to be done under protection of f_lock. This allows the removal of some BKL usage and fixes a number of longstanding (if microscopic) races. Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'fs/ioctl.c')
-rw-r--r--fs/ioctl.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 240ec63984c..421aab465da 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -404,10 +404,12 @@ static int ioctl_fionbio(struct file *filp, int __user *argp)
if (O_NONBLOCK != O_NDELAY)
flag |= O_NDELAY;
#endif
+ spin_lock(&filp->f_lock);
if (on)
filp->f_flags |= flag;
else
filp->f_flags &= ~flag;
+ spin_unlock(&filp->f_lock);
return error;
}
@@ -432,10 +434,12 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp,
if (error)
return error;
+ spin_lock(&filp->f_lock);
if (on)
filp->f_flags |= FASYNC;
else
filp->f_flags &= ~FASYNC;
+ spin_unlock(&filp->f_lock);
return error;
}
@@ -499,10 +503,7 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
break;
case FIONBIO:
- /* BKL needed to avoid races tweaking f_flags */
- lock_kernel();
error = ioctl_fionbio(filp, argp);
- unlock_kernel();
break;
case FIOASYNC: