From 4a6a4499693a419a20559c41e33a7bd70bf20a6f Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Fri, 27 Mar 2009 12:24:31 -0600 Subject: Fix a lockdep warning in fasync_helper() Lockdep gripes if file->f_lock is taken in a no-IRQ situation, since that is not always the case. We don't really want to disable IRQs for every acquisition of f_lock; instead, just move it outside of fasync_lock. Reported-by: Bartlomiej Zolnierkiewicz Reported-by: Larry Finger Reported-by: Wu Fengguang Signed-off-by: Jonathan Corbet --- fs/fcntl.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/fcntl.c b/fs/fcntl.c index d865ca66ccba..cc8e4de2fee5 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -531,6 +531,12 @@ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fap if (!new) return -ENOMEM; } + + /* + * We need to take f_lock first since it's not an IRQ-safe + * lock. + */ + spin_lock(&filp->f_lock); write_lock_irq(&fasync_lock); for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { if (fa->fa_file == filp) { @@ -555,14 +561,12 @@ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fap result = 1; } out: - /* Fix up FASYNC bit while still holding fasync_lock */ - spin_lock(&filp->f_lock); if (on) filp->f_flags |= FASYNC; else filp->f_flags &= ~FASYNC; - spin_unlock(&filp->f_lock); write_unlock_irq(&fasync_lock); + spin_unlock(&filp->f_lock); return result; } -- cgit v1.2.3