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path: root/drivers/tty/pty.c
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Diffstat (limited to 'drivers/tty/pty.c')
-rw-r--r--drivers/tty/pty.c63
1 files changed, 30 insertions, 33 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index e16a49b507ef..0058d9fbf931 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -663,14 +663,14 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
/* this is called once with whichever end is closed last */
static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
{
- struct inode *ptmx_inode;
+ struct pts_fs_info *fsi;
if (tty->driver->subtype == PTY_TYPE_MASTER)
- ptmx_inode = tty->driver_data;
+ fsi = tty->driver_data;
else
- ptmx_inode = tty->link->driver_data;
- devpts_kill_index(ptmx_inode, tty->index);
- devpts_del_ref(ptmx_inode);
+ fsi = tty->link->driver_data;
+ devpts_kill_index(fsi, tty->index);
+ devpts_put_ref(fsi);
}
static const struct tty_operations ptm_unix98_ops = {
@@ -720,6 +720,7 @@ static const struct tty_operations pty_unix98_ops = {
static int ptmx_open(struct inode *inode, struct file *filp)
{
+ struct pts_fs_info *fsi;
struct tty_struct *tty;
struct inode *slave_inode;
int retval;
@@ -734,47 +735,41 @@ static int ptmx_open(struct inode *inode, struct file *filp)
if (retval)
return retval;
+ fsi = devpts_get_ref(inode, filp);
+ retval = -ENODEV;
+ if (!fsi)
+ goto out_free_file;
+
/* find a device that is not in use. */
mutex_lock(&devpts_mutex);
- index = devpts_new_index(inode);
- if (index < 0) {
- retval = index;
- mutex_unlock(&devpts_mutex);
- goto err_file;
- }
-
+ index = devpts_new_index(fsi);
mutex_unlock(&devpts_mutex);
- mutex_lock(&tty_mutex);
- tty = tty_init_dev(ptm_driver, index);
+ retval = index;
+ if (index < 0)
+ goto out_put_ref;
- if (IS_ERR(tty)) {
- retval = PTR_ERR(tty);
- goto out;
- }
+ mutex_lock(&tty_mutex);
+ tty = tty_init_dev(ptm_driver, index);
/* The tty returned here is locked so we can safely
drop the mutex */
mutex_unlock(&tty_mutex);
- set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
- tty->driver_data = inode;
+ retval = PTR_ERR(tty);
+ if (IS_ERR(tty))
+ goto out;
/*
- * In the case where all references to ptmx inode are dropped and we
- * still have /dev/tty opened pointing to the master/slave pair (ptmx
- * is closed/released before /dev/tty), we must make sure that the inode
- * is still valid when we call the final pty_unix98_shutdown, thus we
- * hold an additional reference to the ptmx inode. For the same /dev/tty
- * last close case, we also need to make sure the super_block isn't
- * destroyed (devpts instance unmounted), before /dev/tty is closed and
- * on its release devpts_kill_index is called.
+ * From here on out, the tty is "live", and the index and
+ * fsi will be killed/put by the tty_release()
*/
- devpts_add_ref(inode);
+ set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
+ tty->driver_data = fsi;
tty_add_file(tty, filp);
- slave_inode = devpts_pty_new(inode,
+ slave_inode = devpts_pty_new(fsi,
MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
tty->link);
if (IS_ERR(slave_inode)) {
@@ -793,12 +788,14 @@ static int ptmx_open(struct inode *inode, struct file *filp)
return 0;
err_release:
tty_unlock(tty);
+ // This will also put-ref the fsi
tty_release(inode, filp);
return retval;
out:
- mutex_unlock(&tty_mutex);
- devpts_kill_index(inode, index);
-err_file:
+ devpts_kill_index(fsi, index);
+out_put_ref:
+ devpts_put_ref(fsi);
+out_free_file:
tty_free_file(filp);
return retval;
}