tty: extract the pty init time special cases

The majority of the remaining init_dev code is pty special cases. We
refactor this code into the driver->install method.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 114 insertions, 12 deletions

diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index c98450023030..c5a192dd00db 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -227,7 +227,58 @@ static void pty_set_termios(struct tty_struct *tty, struct ktermios *old_termios
         tty->termios->c_cflag |= (CS8 | CREAD);
 }
 
+static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+        struct tty_struct *o_tty;
+        int idx = tty->index;
+        int retval;
+
+        o_tty = alloc_tty_struct();
+        if (!o_tty)
+                return -ENOMEM;
+        if (!try_module_get(driver->other->owner)) {
+                /* This cannot in fact currently happen */
+                free_tty_struct(o_tty);
+                return -ENOMEM;
+        }
+        initialize_tty_struct(o_tty, driver->other, idx);
+
+        /* We always use new tty termios data so we can do this
+           the easy way .. */
+        retval = tty_init_termios(tty);
+        if (retval)
+                goto free_mem_out;
+
+        retval = tty_init_termios(o_tty);
+        if (retval) {
+                tty_free_termios(tty);
+                goto free_mem_out;
+        }
+        
+        /*
+         * Everything allocated ... set up the o_tty structure.
+         */
+        driver->other->ttys[idx] = o_tty;
+        tty_driver_kref_get(driver->other);
+        if (driver->subtype == PTY_TYPE_MASTER)
+                o_tty->count++;
+        /* Establish the links in both directions */
+        tty->link   = o_tty;
+        o_tty->link = tty;
+
+        tty_driver_kref_get(driver);
+        tty->count++;
+        driver->ttys[idx] = tty;
+        return 0;
+free_mem_out:
+        module_put(o_tty->driver->owner);
+        free_tty_struct(o_tty);
+        return -ENOMEM;
+}
+
+
 static const struct tty_operations pty_ops = {
+        .install = pty_install,
         .open = pty_open,
         .close = pty_close,
         .write = pty_write,
@@ -332,6 +383,7 @@ static inline void legacy_pty_init(void) { }
 int pty_limit = NR_UNIX98_PTY_DEFAULT;
 static int pty_limit_min = 0;
 static int pty_limit_max = NR_UNIX98_PTY_MAX;
+static int pty_count = 0;
 
 static struct cdev ptmx_cdev;
 
@@ -351,6 +403,7 @@ static struct ctl_table pty_table[] = {
                 .procname       = "nr",
                 .maxlen         = sizeof(int),
                 .mode           = 0444,
+                .data           = &pty_count,
                 .proc_handler   = &proc_dointvec,
         }, {
                 .ctl_name       = 0
@@ -426,7 +479,7 @@ static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, int idx)
         return tty;
 }
 
-static void pty_shutdown(struct tty_struct *tty)
+static void pty_unix98_shutdown(struct tty_struct *tty)
 {
         /* We have our own method as we don't use the tty index */
         kfree(tty->termios);
@@ -436,19 +489,71 @@ static void pty_shutdown(struct tty_struct *tty)
 /* We have no need to install and remove our tty objects as devpts does all
    the work for us */
 
-static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
+static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 {
+        struct tty_struct *o_tty;
+        int idx = tty->index;
+
+        o_tty = alloc_tty_struct();
+        if (!o_tty)
+                return -ENOMEM;
+        if (!try_module_get(driver->other->owner)) {
+                /* This cannot in fact currently happen */
+                free_tty_struct(o_tty);
+                return -ENOMEM;
+        }
+        initialize_tty_struct(o_tty, driver->other, idx);
+
+        tty->termios = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+        if (tty->termios == NULL)
+                goto free_mem_out;
+        *tty->termios = driver->init_termios;
+        tty->termios_locked = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
+        if (tty->termios_locked == NULL)
+                goto free_mem_out;
+        o_tty->termios = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+        if (o_tty->termios == NULL)
+                goto free_mem_out;
+        *o_tty->termios = driver->other->init_termios;
+        o_tty->termios_locked = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
+        if (o_tty->termios_locked == NULL)
+                goto free_mem_out;
+
+        tty_driver_kref_get(driver->other);
+        if (driver->subtype == PTY_TYPE_MASTER)
+                o_tty->count++;
+        /* Establish the links in both directions */
+        tty->link   = o_tty;
+        o_tty->link = tty;
+        /*
+         * All structures have been allocated, so now we install them.
+         * Failures after this point use release_tty to clean up, so
+         * there's no need to null out the local pointers.
+         */
+        tty_driver_kref_get(driver);
+        tty->count++;
+        pty_count++;
         return 0;
+free_mem_out:
+        kfree(o_tty->termios);
+        module_put(o_tty->driver->owner);
+        free_tty_struct(o_tty);
+        kfree(tty->termios_locked);
+        kfree(tty->termios);
+        free_tty_struct(tty);
+        module_put(driver->owner);
+        return -ENOMEM;
 }
 
-static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
+static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 {
+        pty_count--;
 }
 
 static const struct tty_operations ptm_unix98_ops = {
         .lookup = ptm_unix98_lookup,
-        .install = pty_install,
-        .remove = pty_remove,
+        .install = pty_unix98_install,
+        .remove = pty_unix98_remove,
         .open = pty_open,
         .close = pty_close,
         .write = pty_write,
@@ -458,13 +563,13 @@ static const struct tty_operations ptm_unix98_ops = {
         .unthrottle = pty_unthrottle,
         .set_termios = pty_set_termios,
         .ioctl = pty_unix98_ioctl,
-        .shutdown = pty_shutdown
+        .shutdown = pty_unix98_shutdown
 };
 
 static const struct tty_operations pty_unix98_ops = {
         .lookup = pts_unix98_lookup,
-        .install = pty_install,
-        .remove = pty_remove,
+        .install = pty_unix98_install,
+        .remove = pty_unix98_remove,
         .open = pty_open,
         .close = pty_close,
         .write = pty_write,
@@ -473,6 +578,7 @@ static const struct tty_operations pty_unix98_ops = {
         .chars_in_buffer = pty_chars_in_buffer,
         .unthrottle = pty_unthrottle,
         .set_termios = pty_set_termios,
+        .shutdown = pty_unix98_shutdown
 };
 
 /**
@@ -589,10 +695,6 @@ static void __init unix98_pty_init(void)
         if (tty_register_driver(pts_driver))
                 panic("Couldn't register Unix98 pts driver");
 
-        /* FIXME: WTF */
-#if 0   
-        pty_table[1].data = &ptm_driver->refcount;
-#endif  
         register_sysctl_table(pty_root_table);  
 
         /* Now create the /dev/ptmx special device */