tty: More driver operations

We have the lookup operation abstracted which is nice for pty cleanup but
we really want to abstract the add/remove entries as well so that we can
pull the pty code out of the tty core and create a clear defined interface
for the tty driver table.

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 0fdfa05171400cf0dd82c1571f99a5f0af34e210..4e6490bda7511eb239e5d97b6230a3faa2cbc3b0 100644 (file)
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -433,8 +433,22 @@ static void pty_shutdown(struct tty_struct *tty)
        kfree(tty->termios_locked);
 }
 
+/* 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)
+{
+       return 0;
+}
+
+static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
+{
+}
+
 static const struct tty_operations ptm_unix98_ops = {
        .lookup = ptm_unix98_lookup,
+       .install = pty_install,
+       .remove = pty_remove,
        .open = pty_open,
        .close = pty_close,
        .write = pty_write,
@@ -449,6 +463,8 @@ static const struct tty_operations ptm_unix98_ops = {
 
 static const struct tty_operations pty_unix98_ops = {
        .lookup = pts_unix98_lookup,
+       .install = pty_install,
+       .remove = pty_remove,
        .open = pty_open,
        .close = pty_close,
        .write = pty_write,

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 47aa437effe204289cb37388968d71c363506fc5..888380f573dcfe622e98303dba398e63ef51c654 100644 (file)
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1189,7 +1189,7 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p)
 }
 
 /**
- *     pty_line_name   -       generate name for a tty
+ *     tty_line_name   -       generate name for a tty
  *     @driver: the tty driver in use
  *     @index: the minor number
  *     @p: output buffer of at least 7 bytes
@@ -1222,13 +1222,51 @@ struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, int idx)
        if (driver->ops->lookup)
                return driver->ops->lookup(driver, idx);
 
-               tty = driver->ttys[idx];
+       tty = driver->ttys[idx];
        return tty;
 }
 
 /**
- *     tty_reopen()    - fast re-open of an open tty
- *     @tty    - the tty to open
+ *     tty_driver_install_tty() - install a tty entry in the driver
+ *     @driver: the driver for the tty
+ *     @tty: the tty
+ *
+ *     Install a tty object into the driver tables. The tty->index field
+ *     will be set by the time this is called.
+ *
+ *     Locking: tty_mutex for now
+ */
+static int tty_driver_install_tty(struct tty_driver *driver,
+                                               struct tty_struct *tty)
+{
+       if (driver->ops->install)
+               return driver->ops->install(driver, tty);
+       driver->ttys[tty->index] = tty;
+       return 0;
+}
+
+/**
+ *     tty_driver_remove_tty() - remove a tty from the driver tables
+ *     @driver: the driver for the tty
+ *     @idx:    the minor number
+ *
+ *     Remvoe a tty object from the driver tables. The tty->index field
+ *     will be set by the time this is called.
+ *
+ *     Locking: tty_mutex for now
+ */
+static void tty_driver_remove_tty(struct tty_driver *driver,
+                                               struct tty_struct *tty)
+{
+       if (driver->ops->remove)
+               driver->ops->remove(driver, tty);
+       else
+               driver->ttys[tty->index] = NULL;
+}
+
+/*
+ *     tty_reopen()    - fast re-open of an open tty
+ *     @tty    - the tty to open
  *
  *     Return 0 on success, -errno on error.
  *
@@ -1423,11 +1461,7 @@ int tty_init_dev(struct tty_driver *driver, int idx,
         * 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.
-        *
-        * FIXME: We want a 'driver->install method ?
         */
-       if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM))
-               driver->ttys[idx] = tty;
 
        if (!*tp_loc)
                *tp_loc = tp;
@@ -1441,6 +1475,9 @@ int tty_init_dev(struct tty_driver *driver, int idx,
        tty_driver_kref_get(driver);
        tty->count++;
 
+       if (tty_driver_install_tty(driver, tty) < 0)
+               goto release_mem_out;
+
        /*
         * Structures all installed ... call the ldisc open routines.
         * If we fail here just call release_tty to clean up.  No need
@@ -1502,7 +1539,7 @@ EXPORT_SYMBOL(tty_free_termios);
 
 void tty_shutdown(struct tty_struct *tty)
 {
-       tty->driver->ttys[tty->index] = NULL;
+       tty_driver_remove_tty(tty->driver, tty);
        tty_free_termios(tty);
 }
 EXPORT_SYMBOL(tty_shutdown);
@@ -1615,7 +1652,7 @@ void tty_release_dev(struct file *filp)
                                  "free (%s)\n", tty->name);
                return;
        }
-       if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
+       if (!devpts) {
                if (tty != tty->driver->ttys[idx]) {
                        printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
                               "for (%s)\n", idx, tty->name);

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index ba891dd23550d1a593b9d2c6707db23fb83edb4b..005d06ad46a62ba987fbf19100630ee1cee7d070 100644 (file)
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -15,6 +15,20 @@
  *
  *     Optional method. Default behaviour is to use the ttys array
  *
+ * int (*install)(struct tty_driver *self, struct tty_struct *tty)
+ *
+ *     Install a new tty into the tty driver internal tables. Used in
+ *     conjunction with lookup and remove methods.
+ *
+ *     Optional method. Default behaviour is to use the ttys array
+ *
+ * void (*remove)(struct tty_driver *self, struct tty_struct *tty)
+ *
+ *     Remove a closed tty from the tty driver internal tables. Used in
+ *     conjunction with lookup and remove methods.
+ *
+ *     Optional method. Default behaviour is to use the ttys array
+ *
  * int  (*open)(struct tty_struct * tty, struct file * filp);
  *
  *     This routine is called when a particular tty device is opened.
@@ -212,6 +226,8 @@ struct tty_driver;
 
 struct tty_operations {
        struct tty_struct * (*lookup)(struct tty_driver *driver, int idx);
+       int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
+       void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
        int  (*open)(struct tty_struct * tty, struct file * filp);
        void (*close)(struct tty_struct * tty, struct file * filp);
        void (*shutdown)(struct tty_struct *tty);