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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 /ipc/mqueue.c
parent684999149002dd046269666a390458e0acb38280 (diff)
downloadlwn-db1dd4d376134eba0e08af523b61cc566a4ea1cd.tar.gz
lwn-db1dd4d376134eba0e08af523b61cc566a4ea1cd.zip
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 'ipc/mqueue.c')
-rw-r--r--ipc/mqueue.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 54b4077fed79..a8ddadbc7459 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -1156,10 +1156,12 @@ SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
if (u_mqstat) {
audit_mq_getsetattr(mqdes, &mqstat);
+ spin_lock(&filp->f_lock);
if (mqstat.mq_flags & O_NONBLOCK)
filp->f_flags |= O_NONBLOCK;
else
filp->f_flags &= ~O_NONBLOCK;
+ spin_unlock(&filp->f_lock);
inode->i_atime = inode->i_ctime = CURRENT_TIME;
}