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pty: Lock the devpts bits privately

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This is a private pty affair, we don't want to tangle it with the tty_lock
any more as we know all the other non tty locking is now handled by the vfs
so we too can move.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Cox 2012-05-03 22:22:09 +01:00 committed by Greg Kroah-Hartman
parent 3af502b966
commit d739e65bb2
1 changed files with 15 additions and 4 deletions

19
drivers/tty/pty.c
View File

@ -26,11 +26,13 @@
#include <linux/bitops.h> #include <linux/bitops.h>
#include <linux/devpts_fs.h> #include <linux/devpts_fs.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/mutex.h>
#ifdef CONFIG_UNIX98_PTYS #ifdef CONFIG_UNIX98_PTYS
static struct tty_driver *ptm_driver; static struct tty_driver *ptm_driver;
static struct tty_driver *pts_driver; static struct tty_driver *pts_driver;
static DEFINE_MUTEX(devpts_mutex);
#endif #endif
static void pty_close(struct tty_struct *tty, struct file *filp) static void pty_close(struct tty_struct *tty, struct file *filp)
@ -54,8 +56,11 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
if (tty->driver->subtype == PTY_TYPE_MASTER) { if (tty->driver->subtype == PTY_TYPE_MASTER) {
set_bit(TTY_OTHER_CLOSED, &tty->flags); set_bit(TTY_OTHER_CLOSED, &tty->flags);
#ifdef CONFIG_UNIX98_PTYS #ifdef CONFIG_UNIX98_PTYS
if (tty->driver == ptm_driver) if (tty->driver == ptm_driver) {
mutex_lock(&devpts_mutex);
devpts_pty_kill(tty->link); devpts_pty_kill(tty->link);
mutex_unlock(&devpts_mutex);
}
#endif #endif
tty_unlock(); tty_unlock();
tty_vhangup(tty->link); tty_vhangup(tty->link);
@ -475,13 +480,17 @@ static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
* @idx: tty index * @idx: tty index
* *
* Look up a pty master device. Called under the tty_mutex for now. * Look up a pty master device. Called under the tty_mutex for now.
* This provides our locking. * This provides our locking for the tty pointer.
*/ */
static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
struct inode *pts_inode, int idx) struct inode *pts_inode, int idx)
{ {
struct tty_struct *tty = devpts_get_tty(pts_inode, idx); struct tty_struct *tty;
mutex_lock(&devpts_mutex);
tty = devpts_get_tty(pts_inode, idx);
mutex_unlock(&devpts_mutex);
/* Master must be open before slave */ /* Master must be open before slave */
if (!tty) if (!tty)
return ERR_PTR(-EIO); return ERR_PTR(-EIO);
@ -622,8 +631,10 @@ static int ptmx_open(struct inode *inode, struct file *filp)
} }
mutex_lock(&tty_mutex); mutex_lock(&tty_mutex);
tty_lock(); mutex_lock(&devpts_mutex);
tty = tty_init_dev(ptm_driver, index); tty = tty_init_dev(ptm_driver, index);
mutex_unlock(&devpts_mutex);
tty_lock();
mutex_unlock(&tty_mutex); mutex_unlock(&tty_mutex);
if (IS_ERR(tty)) { if (IS_ERR(tty)) {