TTY: pty, switch to tty_alloc_driver

Switch to the new driver allocation interface, as this is one of the
special call-sites. Here, we need TTY_DRIVER_DYNAMIC_ALLOC to not
allocate tty_driver->ports, cdevs and potentially other structures
because we reserve too many lines in pty. Instead, it provides the
tty_port<->tty_struct link in tty->ops->install already.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 3adc362f0bd..1a85f003d64 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -391,6 +391,9 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
  *      the requested timeout to the caller instead of using a simple
  *      on/off interface.
  *
+ * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are
+ *      needed per line for this driver as it would waste memory.
+ *      The driver will take care.
  */
 #define TTY_DRIVER_INSTALLED            0x0001
 #define TTY_DRIVER_RESET_TERMIOS        0x0002
@@ -398,6 +401,7 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 #define TTY_DRIVER_DYNAMIC_DEV          0x0008
 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
+#define TTY_DRIVER_DYNAMIC_ALLOC        0x0040
 
 /* tty driver types */
 #define TTY_DRIVER_TYPE_SYSTEM          0x0001