tty: Remove more special casing and out of place code
Carry on pushing code out of tty_io when it belongs to other drivers. I'm
not 100% happy with some of this and it will be worth revisiting some of the
exports later when the restructuring work is done.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index ec09c1c..328e8ac 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -23,6 +23,7 @@
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/sysctl.h>
+#include <linux/device.h>
#include <asm/uaccess.h>
#include <asm/system.h>
@@ -332,6 +333,8 @@
static int pty_limit_min = 0;
static int pty_limit_max = NR_UNIX98_PTY_MAX;
+static struct cdev ptmx_cdev;
+
static struct ctl_table pty_table[] = {
{
.ctl_name = PTY_MAX,
@@ -408,6 +411,70 @@
.shutdown = pty_shutdown
};
+
+/**
+ * ptmx_open - open a unix 98 pty master
+ * @inode: inode of device file
+ * @filp: file pointer to tty
+ *
+ * Allocate a unix98 pty master device from the ptmx driver.
+ *
+ * Locking: tty_mutex protects the init_dev work. tty->count should
+ * protect the rest.
+ * allocated_ptys_lock handles the list of free pty numbers
+ */
+
+static int __ptmx_open(struct inode *inode, struct file *filp)
+{
+ struct tty_struct *tty;
+ int retval;
+ int index;
+
+ nonseekable_open(inode, filp);
+
+ /* find a device that is not in use. */
+ index = devpts_new_index();
+ if (index < 0)
+ return index;
+
+ mutex_lock(&tty_mutex);
+ retval = tty_init_dev(ptm_driver, index, &tty, 1);
+ mutex_unlock(&tty_mutex);
+
+ if (retval)
+ goto out;
+
+ set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
+ filp->private_data = tty;
+ file_move(filp, &tty->tty_files);
+
+ retval = devpts_pty_new(tty->link);
+ if (retval)
+ goto out1;
+
+ retval = ptm_driver->ops->open(tty, filp);
+ if (!retval)
+ return 0;
+out1:
+ tty_release_dev(filp);
+ return retval;
+out:
+ devpts_kill_index(index);
+ return retval;
+}
+
+static int ptmx_open(struct inode *inode, struct file *filp)
+{
+ int ret;
+
+ lock_kernel();
+ ret = __ptmx_open(inode, filp);
+ unlock_kernel();
+ return ret;
+}
+
+static struct file_operations ptmx_fops;
+
static void __init unix98_pty_init(void)
{
ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
@@ -459,7 +526,18 @@
pty_table[1].data = &ptm_driver->refcount;
register_sysctl_table(pty_root_table);
+
+ /* Now create the /dev/ptmx special device */
+ tty_default_fops(&ptmx_fops);
+ ptmx_fops.open = ptmx_open;
+
+ cdev_init(&ptmx_cdev, &ptmx_fops);
+ if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
+ register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
+ panic("Couldn't register /dev/ptmx driver\n");
+ device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
}
+
#else
static inline void unix98_pty_init(void) { }
#endif