From 36ba782e9674cdc29ec7003757df0b375e99fa96 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 30 Nov 2009 13:18:51 +0000
Subject: [PATCH] tty: split the lock up a bit further
The tty count sanity check may need the BKL, that isn't clear. However it
is clear that the count use of the lock is internal and independant of the
bigger use of the lock.
Furthermore the file list locking is also separately locked already
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/char/tty_io.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index a19fef2093f1d..684f0e0b175ed 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -516,6 +516,8 @@ static void do_tty_hangup(struct work_struct *work)
/* inuse_filps is protected by the single kernel lock */
lock_kernel();
check_tty_count(tty, "do_tty_hangup");
+ unlock_kernel();
+
file_list_lock();
/* This breaks for file handles being sent over AF_UNIX sockets ? */
list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
@@ -529,6 +531,7 @@ static void do_tty_hangup(struct work_struct *work)
}
file_list_unlock();
+ lock_kernel();
tty_ldisc_hangup(tty);
read_lock(&tasklist_lock);
--
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