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authorPeter Hurley <peter@hurleysoftware.com>2013-06-15 07:04:48 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-23 16:38:34 -0700
commit36697529b5bbe36911e39a6309e7a7c9250d280a (patch)
tree5cbffa976994cb798e00d60eccb46c6cafc369a1 /include/linux/tty_ldisc.h
parentd2c438905f9f718b3d9f5d89ce163fc22bd33995 (diff)
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op-kernel-dev-36697529b5bbe36911e39a6309e7a7c9250d280a.tar.gz
tty: Replace ldisc locking with ldisc_sem
Line discipline locking was performed with a combination of a mutex, a status bit, a count, and a waitqueue -- basically, a rw semaphore. Replace the existing combination with an ld_semaphore. Fixes: 1) the 'reference acquire after ldisc locked' bug 2) the over-complicated halt mechanism 3) lock order wrt. tty_lock() 4) dropping locks while changing ldisc 5) previously unidentified deadlock while locking ldisc from both linked ttys concurrently 6) previously unidentified recursive deadlocks Adds much-needed lockdep diagnostics. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/tty_ldisc.h')
-rw-r--r--include/linux/tty_ldisc.h3
1 files changed, 1 insertions, 2 deletions
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index a1b0489..23bdd9d 100644
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -203,8 +203,7 @@ struct tty_ldisc_ops {
struct tty_ldisc {
struct tty_ldisc_ops *ops;
- atomic_t users;
- wait_queue_head_t wq_idle;
+ struct tty_struct *tty;
};
#define TTY_LDISC_MAGIC 0x5403
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