Merge branch 'linus' into core/rcu

Conflicts:
	fs/fs-writeback.c

Merge reason: Resolve the conflict

Note, i picked the version from Linus's tree, which effectively reverts
the fs-writeback.c bits of:

  b97181f: fs: remove all rcu head initializations, except on_stack initializations

As the upstream changes to this file changed this code heavily and the
first attempt to resolve the conflict resulted in a non-booting kernel.
It's safer to re-try this portion of the commit cleanly.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 13 deletions

diff --git a/drivers/usb/gadget/u_serial.c b/drivers/usb/gadget/u_serial.c
index 16bdf77f582a..3e8dcb5455e3 100644
--- a/drivers/usb/gadget/u_serial.c
+++ b/drivers/usb/gadget/u_serial.c
@@ -536,17 +536,11 @@ recycle:
                 list_move(&req->list, &port->read_pool);
         }
 
-        /* Push from tty to ldisc; this is immediate with low_latency, and
-         * may trigger callbacks to this driver ... so drop the spinlock.
+        /* Push from tty to ldisc; without low_latency set this is handled by
+         * a workqueue, so we won't get callbacks and can hold port_lock
          */
         if (tty && do_push) {
-                spin_unlock_irq(&port->port_lock);
                 tty_flip_buffer_push(tty);
-                wake_up_interruptible(&tty->read_wait);
-                spin_lock_irq(&port->port_lock);
-
-                /* tty may have been closed */
-                tty = port->port_tty;
         }
 
 
@@ -784,11 +778,6 @@ static int gs_open(struct tty_struct *tty, struct file *file)
         port->open_count = 1;
         port->openclose = false;
 
-        /* low_latency means ldiscs work in tasklet context, without
-         * needing a workqueue schedule ... easier to keep up.
-         */
-        tty->low_latency = 1;
-
         /* if connected, start the I/O stream */
         if (port->port_usb) {
                 struct gserial  *gser = port->port_usb;
@@ -1195,6 +1184,7 @@ void gserial_cleanup(void)
         n_ports = 0;
 
         tty_unregister_driver(gs_tty_driver);
+        put_tty_driver(gs_tty_driver);
         gs_tty_driver = NULL;
 
         pr_debug("%s: cleaned up ttyGS* support\n", __func__);