tty: tty_port: Change the buffer allocator locking

We want to be able to do this without regard for the activate/own open
method being used which causes a problem using port->mutex. Add another
mutex for now. Once everything uses port_open to do buffer allocs we can
kill it back off

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 6352ac257fcb..e9269ca1542a 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -212,6 +212,7 @@ struct tty_port {
         wait_queue_head_t       delta_msr_wait; /* Modem status change */
         unsigned long           flags;          /* TTY flags ASY_*/
         struct mutex            mutex;          /* Locking */
+        struct mutex            buf_mutex;      /* Buffer alloc lock */
         unsigned char           *xmit_buf;      /* Optional buffer */
         unsigned int            close_delay;    /* Close port delay */
         unsigned int            closing_wait;   /* Delay for output */