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>
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index b0ad488..e881e9e 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -136,8 +136,6 @@
DEFINE_MUTEX(tty_mutex);
EXPORT_SYMBOL(tty_mutex);
-static void initialize_tty_struct(struct tty_struct *tty);
-
static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
ssize_t redirected_tty_write(struct file *, const char __user *,
@@ -166,7 +164,7 @@
* Locking: none
*/
-static struct tty_struct *alloc_tty_struct(void)
+struct tty_struct *alloc_tty_struct(void)
{
return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
}
@@ -180,7 +178,7 @@
* Locking: none. Must be called after tty is definitely unused
*/
-static inline void free_tty_struct(struct tty_struct *tty)
+void free_tty_struct(struct tty_struct *tty)
{
kfree(tty->write_buf);
tty_buffer_free_all(tty);
@@ -1227,22 +1225,70 @@
}
/**
+ * tty_init_termios - helper for termios setup
+ * @tty: the tty to set up
+ *
+ * Initialise the termios structures for this tty. Thus runs under
+ * the tty_mutex currently so we can be relaxed about ordering.
+ */
+
+int tty_init_termios(struct tty_struct *tty)
+{
+ struct ktermios *tp, *ltp;
+ int idx = tty->index;
+
+ tp = tty->driver->termios[idx];
+ ltp = tty->driver->termios_locked[idx];
+ if (tp == NULL) {
+ WARN_ON(ltp != NULL);
+ tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
+ ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
+ if (tp == NULL || ltp == NULL) {
+ kfree(tp);
+ kfree(ltp);
+ return -ENOMEM;
+ }
+ memcpy(tp, &tty->driver->init_termios,
+ sizeof(struct ktermios));
+ tty->driver->termios[idx] = tp;
+ tty->driver->termios_locked[idx] = ltp;
+ }
+ tty->termios = tp;
+ tty->termios_locked = ltp;
+
+ /* Compatibility until drivers always set this */
+ tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
+ tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
+ return 0;
+}
+
+/**
* 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.
+ * will be set by the time this is called. This method is responsible
+ * for ensuring any need additional structures are allocated and
+ * configured.
*
* Locking: tty_mutex for now
*/
static int tty_driver_install_tty(struct tty_driver *driver,
struct tty_struct *tty)
{
+ int idx = tty->index;
+
if (driver->ops->install)
return driver->ops->install(driver, tty);
- driver->ttys[tty->index] = tty;
- return 0;
+
+ if (tty_init_termios(tty) == 0) {
+ tty_driver_kref_get(driver);
+ tty->count++;
+ driver->ttys[idx] = tty;
+ return 0;
+ }
+ return -ENOMEM;
}
/**
@@ -1327,9 +1373,7 @@
struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
int first_ok)
{
- struct tty_struct *tty, *o_tty;
- struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
- struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
+ struct tty_struct *tty;
int retval;
/* check whether we're reopening an existing tty */
@@ -1361,118 +1405,17 @@
if (!try_module_get(driver->owner))
return ERR_PTR(-ENODEV);
- o_tty = NULL;
- tp = o_tp = NULL;
- ltp = o_ltp = NULL;
-
tty = alloc_tty_struct();
if (!tty)
goto fail_no_mem;
- initialize_tty_struct(tty);
- tty->driver = driver;
- tty->ops = driver->ops;
- tty->index = idx;
- tty_line_name(driver, idx, tty->name);
-
- if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
- tp_loc = &tty->termios;
- ltp_loc = &tty->termios_locked;
- } else {
- tp_loc = &driver->termios[idx];
- ltp_loc = &driver->termios_locked[idx];
- }
-
- if (!*tp_loc) {
- tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
- if (!tp)
- goto free_mem_out;
- *tp = driver->init_termios;
- }
-
- if (!*ltp_loc) {
- ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
- if (!ltp)
- goto free_mem_out;
- }
-
- if (driver->type == TTY_DRIVER_TYPE_PTY) {
- o_tty = alloc_tty_struct();
- if (!o_tty)
- goto free_mem_out;
- if (!try_module_get(driver->other->owner)) {
- /* This cannot in fact currently happen */
- free_tty_struct(o_tty);
- o_tty = NULL;
- goto free_mem_out;
- }
- initialize_tty_struct(o_tty);
- o_tty->driver = driver->other;
- o_tty->ops = driver->ops;
- o_tty->index = idx;
- tty_line_name(driver->other, idx, o_tty->name);
-
- if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
- o_tp_loc = &o_tty->termios;
- o_ltp_loc = &o_tty->termios_locked;
- } else {
- o_tp_loc = &driver->other->termios[idx];
- o_ltp_loc = &driver->other->termios_locked[idx];
- }
-
- if (!*o_tp_loc) {
- o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
- if (!o_tp)
- goto free_mem_out;
- *o_tp = driver->other->init_termios;
- }
-
- if (!*o_ltp_loc) {
- o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL);
- if (!o_ltp)
- goto free_mem_out;
- }
-
- /*
- * Everything allocated ... set up the o_tty structure.
- */
- if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM))
- driver->other->ttys[idx] = o_tty;
- if (!*o_tp_loc)
- *o_tp_loc = o_tp;
- if (!*o_ltp_loc)
- *o_ltp_loc = o_ltp;
- o_tty->termios = *o_tp_loc;
- o_tty->termios_locked = *o_ltp_loc;
- 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.
- */
-
- if (!*tp_loc)
- *tp_loc = tp;
- if (!*ltp_loc)
- *ltp_loc = ltp;
- tty->termios = *tp_loc;
- tty->termios_locked = *ltp_loc;
- /* Compatibility until drivers always set this */
- tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
- tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
- tty_driver_kref_get(driver);
- tty->count++;
+ initialize_tty_struct(tty, driver, idx);
retval = tty_driver_install_tty(driver, tty);
- if (retval < 0)
- goto release_mem_out;
+ if (retval < 0) {
+ free_tty_struct(tty);
+ module_put(driver->owner);
+ return ERR_PTR(retval);
+ }
/*
* Structures all installed ... call the ldisc open routines.
@@ -1480,22 +1423,11 @@
* to decrement the use counts, as release_tty doesn't care.
*/
- retval = tty_ldisc_setup(tty, o_tty);
+ retval = tty_ldisc_setup(tty, tty->link);
if (retval)
goto release_mem_out;
return tty;
- /* Release locally allocated memory ... nothing placed in slots */
-free_mem_out:
- kfree(o_tp);
- if (o_tty) {
- module_put(o_tty->driver->owner);
- free_tty_struct(o_tty);
- }
- kfree(ltp);
- kfree(tp);
- free_tty_struct(tty);
-
fail_no_mem:
module_put(driver->owner);
return ERR_PTR(-ENOMEM);
@@ -2852,7 +2784,8 @@
* Locking: none - tty in question must not be exposed at this point
*/
-static void initialize_tty_struct(struct tty_struct *tty)
+void initialize_tty_struct(struct tty_struct *tty,
+ struct tty_driver *driver, int idx)
{
memset(tty, 0, sizeof(struct tty_struct));
kref_init(&tty->kref);
@@ -2873,6 +2806,11 @@
spin_lock_init(&tty->ctrl_lock);
INIT_LIST_HEAD(&tty->tty_files);
INIT_WORK(&tty->SAK_work, do_SAK_work);
+
+ tty->driver = driver;
+ tty->ops = driver->ops;
+ tty->index = idx;
+ tty_line_name(driver, idx, tty->name);
}
/**