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Subject[PATCH 18/41] TTY: pty, switch to tty_alloc_driver
Date
Switch to the new driver allocation interface, as this is one of the
special call-sites. Here, we need TTY_DRIVER_EXCESSIVE_LINES 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>
---
drivers/tty/pty.c | 31 ++++++++++++++++++++-----------
include/linux/tty_driver.h | 4 ++++
2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index b726c8b..e44a11d 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -443,11 +443,17 @@ static void __init legacy_pty_init(void)
if (legacy_count <= 0)
return;

- pty_driver = alloc_tty_driver(legacy_count);
+ pty_driver = tty_alloc_driver(legacy_count,
+ TTY_DRIVER_RESET_TERMIOS |
+ TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_EXCESSIVE_LINES);
if (!pty_driver)
panic("Couldn't allocate pty driver");

- pty_slave_driver = alloc_tty_driver(legacy_count);
+ pty_slave_driver = tty_alloc_driver(legacy_count,
+ TTY_DRIVER_RESET_TERMIOS |
+ TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_EXCESSIVE_LINES);
if (!pty_slave_driver)
panic("Couldn't allocate pty slave driver");

@@ -464,7 +470,6 @@ static void __init legacy_pty_init(void)
pty_driver->init_termios.c_lflag = 0;
pty_driver->init_termios.c_ispeed = 38400;
pty_driver->init_termios.c_ospeed = 38400;
- pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
pty_driver->other = pty_slave_driver;
tty_set_operations(pty_driver, &master_pty_ops_bsd);

@@ -478,8 +483,6 @@ static void __init legacy_pty_init(void)
pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
pty_slave_driver->init_termios.c_ispeed = 38400;
pty_slave_driver->init_termios.c_ospeed = 38400;
- pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
- TTY_DRIVER_REAL_RAW;
pty_slave_driver->other = pty_driver;
tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);

@@ -670,10 +673,20 @@ static struct file_operations ptmx_fops;

static void __init unix98_pty_init(void)
{
- ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
+ ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
+ TTY_DRIVER_RESET_TERMIOS |
+ TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_DYNAMIC_DEV |
+ TTY_DRIVER_DEVPTS_MEM |
+ TTY_DRIVER_EXCESSIVE_LINES);
if (!ptm_driver)
panic("Couldn't allocate Unix98 ptm driver");
- pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
+ pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
+ TTY_DRIVER_RESET_TERMIOS |
+ TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_DYNAMIC_DEV |
+ TTY_DRIVER_DEVPTS_MEM |
+ TTY_DRIVER_EXCESSIVE_LINES);
if (!pts_driver)
panic("Couldn't allocate Unix98 pts driver");

@@ -690,8 +703,6 @@ static void __init unix98_pty_init(void)
ptm_driver->init_termios.c_lflag = 0;
ptm_driver->init_termios.c_ispeed = 38400;
ptm_driver->init_termios.c_ospeed = 38400;
- ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
- TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
ptm_driver->other = pts_driver;
tty_set_operations(ptm_driver, &ptm_unix98_ops);

@@ -705,8 +716,6 @@ static void __init unix98_pty_init(void)
pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
pts_driver->init_termios.c_ispeed = 38400;
pts_driver->init_termios.c_ospeed = 38400;
- pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
- TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
pts_driver->other = ptm_driver;
tty_set_operations(pts_driver, &pty_unix98_ops);

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 3adc362..bea95ca 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_EXCESSIVE_LINES -- do not allocate structures which are
+ * needed per line for this driver as it would waste memory.
+ * Applicable only to pty.
*/
#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_EXCESSIVE_LINES 0x0040

/* tty driver types */
#define TTY_DRIVER_TYPE_SYSTEM 0x0001
--
1.7.10.4



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