From: Sukadev Bhattiprolu <[EMAIL PROTECTED]>
Subject: [RFC][PATCH 3/3] Rename and change init_dev() prototype
init_dev() takes an additional '*ret_tty' parameter so it can either return
a valid 'tty_struct *' (on success) or an integer error code on failure.
Drop the '*ret_tty' and return either a tty_struct * or ERR_PTR().
Also since init_dev() now only handles the (slow) open of a _new_ tty,
rename to alloc_init_dev().
---
drivers/char/tty_io.c | 56 ++++++++++++++++++++++++++------------------------
1 file changed, 30 insertions(+), 26 deletions(-)
Index: linux-next/drivers/char/tty_io.c
===================================================================
--- linux-next.orig/drivers/char/tty_io.c 2008-08-25 12:54:35.000000000
-0700
+++ linux-next/drivers/char/tty_io.c 2008-08-25 12:56:30.000000000 -0700
@@ -1290,7 +1290,7 @@ static int fast_tty_open(struct tty_stru
}
/**
- * init_dev - initialise a tty device
+ * alloc_init_dev - alloc/initialise a new tty device
* @driver: tty driver we are opening a device on
* @idx: device index
* @ret_tty: returned tty structure
@@ -1314,20 +1314,19 @@ static int fast_tty_open(struct tty_stru
* relaxed for the (most common) case of reopening a tty.
*/
-static int init_dev(struct tty_driver *driver, int idx,
- struct tty_struct **ret_tty, int first_ok)
+static struct tty_struct *alloc_init_dev(struct tty_driver *driver, int idx,
+ int first_ok)
{
- struct tty_struct *tty, *o_tty;
+ struct tty_struct *tty, *o_tty, *ret_tty;
struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
- int retval = 0;
+ int err;
/* Check if pty master is being opened multiple times */
+ ret_tty = ERR_PTR(-EIO);
if (driver->subtype == PTY_TYPE_MASTER &&
- (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
- retval = -EIO;
+ (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok)
goto end_init;
- }
/*
* First time open is complex, especially for PTY devices.
* This code guarantees that either everything succeeds and the
@@ -1336,10 +1335,9 @@ static int init_dev(struct tty_driver *d
* and locked termios may be retained.)
*/
- if (!try_module_get(driver->owner)) {
- retval = -ENODEV;
+ ret_tty = ERR_PTR(-ENODEV);
+ if (!try_module_get(driver->owner))
goto end_init;
- }
o_tty = NULL;
tp = o_tp = NULL;
@@ -1348,6 +1346,7 @@ static int init_dev(struct tty_driver *d
tty = alloc_tty_struct();
if (!tty)
goto fail_no_mem;
+
initialize_tty_struct(tty);
tty->driver = driver;
tty->ops = driver->ops;
@@ -1458,16 +1457,15 @@ static int init_dev(struct tty_driver *d
* to decrement the use counts, as release_tty doesn't care.
*/
- retval = tty_ldisc_setup(tty, o_tty);
-
- if (retval)
+ err = tty_ldisc_setup(tty, o_tty);
+ if (err)
goto release_mem_out;
- *ret_tty = tty;
+ ret_tty = tty;
/* All paths come through here to release the mutex */
end_init:
- return retval;
+ return ret_tty;
/* Release locally allocated memory ... nothing placed in slots */
free_mem_out:
@@ -1482,13 +1480,13 @@ free_mem_out:
fail_no_mem:
module_put(driver->owner);
- retval = -ENOMEM;
+ ret_tty = ERR_PTR(-ENOMEM);
goto end_init;
/* call the tty release_tty routine to clean out this slot */
release_mem_out:
if (printk_ratelimit())
- printk(KERN_INFO "init_dev: ldisc open failed, "
+ printk(KERN_INFO "alloc_init_dev: ldisc open failed, "
"clearing slot %d\n", idx);
release_tty(tty, idx);
goto end_init;
@@ -1910,8 +1908,11 @@ got_driver:
if (tty)
retval = fast_tty_open(tty);
- else
- retval = init_dev(driver, index, &tty, 0);
+ else {
+ tty = alloc_init_dev(driver, index, 0);
+ if (IS_ERR(tty))
+ retval = PTR_ERR(tty);
+ }
mutex_unlock(&tty_mutex);
@@ -2007,7 +2008,7 @@ static struct tty_struct *find_open_tty(
*
* Allocate a unix98 pty master device from the ptmx driver.
*
- * Locking: tty_mutex protects the find_open_tty and init_dev work.
+ * Locking: tty_mutex protects the find_open_tty and alloc_init_dev work.
* tty->count should protect the rest.
* allocated_ptys_lock handles the list of free pty numbers
*/
@@ -2033,15 +2034,18 @@ static int __ptmx_open(struct inode *ino
* old init_dev().
*/
tty = find_open_tty(ptm_driver, index);
- if (IS_ERR(tty))
- retval = PTR_ERR(tty);
- else if (!tty)
- retval = init_dev(ptm_driver, index, &tty, 1);
+
+ if (!tty)
+ tty = alloc_init_dev(ptm_driver, index, 1);
mutex_unlock(&tty_mutex);
- if (retval)
+ BUG_ON(tty == NULL); /* TODO: remove */
+
+ if (IS_ERR(tty)) {
+ retval = PTR_ERR(tty);
goto out;
+ }
set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
filp->private_data = tty;
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