diff options
author | Paolo Bonzini <pbonzini@redhat.com> | 2016-01-26 18:28:36 +0300 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-01-26 18:28:36 +0300 |
commit | b8bc3bde9c8c90500c648627d53f846642ff8639 (patch) | |
tree | 0c3ed82848a25948206556bc699a10d30bd18d07 /drivers/tty/tty_ldisc.c | |
parent | 171b5682aa8597174e80ec4128c87538103f2213 (diff) | |
parent | 9abc2a08a7d665b02bdde974fd6c44aae86e923e (diff) | |
download | linux-b8bc3bde9c8c90500c648627d53f846642ff8639.tar.xz |
Merge tag 'kvm-s390-master-4.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
KVM: s390: Fixes for kvm/master (targeting 4.5)
1. Fallout of some bigger floating point/vector rework in s390
- memory leak -> stable 4.3+
- memory overwrite -> stable 4.4+
2. enable KVM-VFIO for s390
Diffstat (limited to 'drivers/tty/tty_ldisc.c')
-rw-r--r-- | drivers/tty/tty_ldisc.c | 51 |
1 files changed, 21 insertions, 30 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 629e3c865072..a054d03c22e7 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -185,7 +185,7 @@ static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc) * * Complement of tty_ldisc_get(). */ -static inline void tty_ldisc_put(struct tty_ldisc *ld) +static void tty_ldisc_put(struct tty_ldisc *ld) { if (WARN_ON_ONCE(!ld)) return; @@ -417,6 +417,10 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush); * they are not on hot paths so a little discipline won't do * any harm. * + * The line discipline-related tty_struct fields are reset to + * prevent the ldisc driver from re-using stale information for + * the new ldisc instance. + * * Locking: takes termios_rwsem */ @@ -425,6 +429,9 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num) down_write(&tty->termios_rwsem); tty->termios.c_line = num; up_write(&tty->termios_rwsem); + + tty->disc_data = NULL; + tty->receive_room = 0; } /** @@ -529,34 +536,21 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) tty_lock(tty); retval = tty_ldisc_lock(tty, 5 * HZ); - if (retval) { - tty_ldisc_put(new_ldisc); - tty_unlock(tty); - return retval; - } + if (retval) + goto err; - /* - * Check the no-op case - */ + /* Check the no-op case */ + if (tty->ldisc->ops->num == ldisc) + goto out; - if (tty->ldisc->ops->num == ldisc) { - tty_ldisc_unlock(tty); - tty_ldisc_put(new_ldisc); - tty_unlock(tty); - return 0; + if (test_bit(TTY_HUPPED, &tty->flags)) { + /* We were raced by hangup */ + retval = -EIO; + goto out; } old_ldisc = tty->ldisc; - if (test_bit(TTY_HUPPED, &tty->flags)) { - /* We were raced by the hangup method. It will have stomped - the ldisc data and closed the ldisc down */ - tty_ldisc_unlock(tty); - tty_ldisc_put(new_ldisc); - tty_unlock(tty); - return -EIO; - } - /* Shutdown the old discipline. */ tty_ldisc_close(tty, old_ldisc); @@ -582,18 +576,15 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) the old ldisc (if it was restored as part of error cleanup above). In either case, releasing a single reference from the old ldisc is correct. */ - - tty_ldisc_put(old_ldisc); - - /* - * Allow ldisc referencing to occur again - */ + new_ldisc = old_ldisc; +out: tty_ldisc_unlock(tty); /* Restart the work queue in case no characters kick it off. Safe if already running */ tty_buffer_restart_work(tty->port); - +err: + tty_ldisc_put(new_ldisc); /* drop the extra reference */ tty_unlock(tty); return retval; } |