[PATCH 3.4 141/177] tty: Prevent "read/write wait queue active!" log flooding

[lizf]

From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>

3.4.106-rc1 review patch.  If anyone has any objections, please let me know.

------------------


commit 494c1eac7e73f719af9d474a96ec8494c33efd6a upstream.

Only print one warning when a task is on the read_wait or write_wait
wait queue at final tty release.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
---
 drivers/tty/tty_io.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 2d66beed..a07eb4c 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1634,6 +1634,7 @@ int tty_release(struct inode *inode, struct file *filp)
 	int	idx;
 	char	buf[64];
 	long	timeout = 0;
+	int	once = 1;
 
 	if (tty_paranoia_check(tty, inode, __func__))
 		return 0;
@@ -1714,8 +1715,11 @@ int tty_release(struct inode *inode, struct file *filp)
 		if (!do_sleep)
 			break;
 
-		printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
+		if (once) {
+			once = 0;
+			printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
 				__func__, tty_name(tty, buf));
+		}
 		tty_unlock();
 		mutex_unlock(&tty_mutex);
 		schedule_timeout_killable(timeout);
-- 
1.9.1

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