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| author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 07:04:48 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-23 16:38:34 -0700 |
| commit | 36697529b5bbe36911e39a6309e7a7c9250d280a (patch) | |
| tree | 5cbffa976994cb798e00d60eccb46c6cafc369a1 /include/linux/tty.h | |
| parent | d2c438905f9f718b3d9f5d89ce163fc22bd33995 (diff) | |
| download | op-kernel-dev-36697529b5bbe36911e39a6309e7a7c9250d280a.zip 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.h')
| -rw-r--r-- | include/linux/tty.h | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h index 01ac30e..7269daf 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -238,7 +238,7 @@ struct tty_struct { int index; /* Protects ldisc changes: Lock tty not pty */ - struct mutex ldisc_mutex; + struct ld_semaphore ldisc_sem; struct tty_ldisc *ldisc; struct mutex atomic_write_lock; @@ -305,8 +305,6 @@ struct tty_file_private { #define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */ #define TTY_PUSH 6 /* n_tty private */ #define TTY_CLOSING 7 /* ->close() in progress */ -#define TTY_LDISC 9 /* Line discipline attached */ -#define TTY_LDISC_CHANGING 10 /* Line discipline changing */ #define TTY_LDISC_OPEN 11 /* Line discipline is open */ #define TTY_PTY_LOCK 16 /* pty private */ #define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */ |
