tty: push the BKL down into the handlers a bit
Start trying to untangle the remaining BKL mess
Updated to fix missing unlock_kernel noted by Dan Carpenter
Signed-off-by: Alan "I must be out of my tree" Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index feb5507..d914e77 100644
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -34,6 +34,8 @@
#include <linux/vt_kern.h>
#include <linux/selection.h>
+#include <linux/smp_lock.h> /* For the moment */
+
#include <linux/kmod.h>
#include <linux/nsproxy.h>
@@ -545,6 +547,7 @@
if (IS_ERR(new_ldisc))
return PTR_ERR(new_ldisc);
+ lock_kernel();
/*
* We need to look at the tty locking here for pty/tty pairs
* when both sides try to change in parallel.
@@ -558,6 +561,7 @@
*/
if (tty->ldisc->ops->num == ldisc) {
+ unlock_kernel();
tty_ldisc_put(new_ldisc);
return 0;
}
@@ -569,6 +573,7 @@
tty_wait_until_sent(tty, 0);
+ unlock_kernel();
mutex_lock(&tty->ldisc_mutex);
/*
@@ -582,6 +587,9 @@
test_bit(TTY_LDISC_CHANGING, &tty->flags) == 0);
mutex_lock(&tty->ldisc_mutex);
}
+
+ lock_kernel();
+
set_bit(TTY_LDISC_CHANGING, &tty->flags);
/*
@@ -592,6 +600,8 @@
tty->receive_room = 0;
o_ldisc = tty->ldisc;
+
+ unlock_kernel();
/*
* Make sure we don't change while someone holds a
* reference to the line discipline. The TTY_LDISC bit
@@ -617,12 +627,14 @@
flush_scheduled_work();
mutex_lock(&tty->ldisc_mutex);
+ lock_kernel();
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 */
clear_bit(TTY_LDISC_CHANGING, &tty->flags);
mutex_unlock(&tty->ldisc_mutex);
tty_ldisc_put(new_ldisc);
+ unlock_kernel();
return -EIO;
}
@@ -664,6 +676,7 @@
if (o_work)
schedule_delayed_work(&o_tty->buf.work, 1);
mutex_unlock(&tty->ldisc_mutex);
+ unlock_kernel();
return retval;
}