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tty: Clean up the tty_init_dev changes further 

Fix up the naming, style and extract some bits of code into the driver
specific code

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox 2008-10-13 10:42:00 +01:00 committed by Linus Torvalds
parent 2349970575
commit 99f1fe189d
3 changed files with 81 additions and 41 deletions
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49
drivers/char/pty.c
View File

@ -391,6 +391,41 @@ static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
return -ENOIOCTLCMD;
}
/**
* ptm_unix98_lookup - find a pty master
* @driver: ptm driver
* @idx: tty index
*
* Look up a pty master device. Called under the tty_mutex for now.
* This provides our locking.
*/
static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, int idx)
{
struct tty_struct *tty = devpts_get_tty(idx);
if (tty)
tty = tty->link;
return tty;
}
/**
* pts_unix98_lookup - find a pty slave
* @driver: pts driver
* @idx: tty index
*
* Look up a pty master device. Called under the tty_mutex for now.
* This provides our locking.
*/
static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, int idx)
{
struct tty_struct *tty = devpts_get_tty(idx);
/* Master must be open before slave */
if (!tty)
return ERR_PTR(-EIO);
return tty;
}
static void pty_shutdown(struct tty_struct *tty)
{
/* We have our own method as we don't use the tty index */
@ -399,6 +434,7 @@ static void pty_shutdown(struct tty_struct *tty)
}
static const struct tty_operations ptm_unix98_ops = {
.lookup = ptm_unix98_lookup,
.open = pty_open,
.close = pty_close,
.write = pty_write,
@ -411,6 +447,17 @@ static const struct tty_operations ptm_unix98_ops = {
.shutdown = pty_shutdown
};
static const struct tty_operations pty_unix98_ops = {
.lookup = pts_unix98_lookup,
.open = pty_open,
.close = pty_close,
.write = pty_write,
.write_room = pty_write_room,
.flush_buffer = pty_flush_buffer,
.chars_in_buffer = pty_chars_in_buffer,
.unthrottle = pty_unthrottle,
.set_termios = pty_set_termios,
};
/**
* ptmx_open - open a unix 98 pty master
@ -517,7 +564,7 @@ static void __init unix98_pty_init(void)
pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
pts_driver->other = ptm_driver;
tty_set_operations(pts_driver, &pty_ops);
tty_set_operations(pts_driver, &pty_unix98_ops);
if (tty_register_driver(ptm_driver))
panic("Couldn't register Unix98 ptm driver");

64
drivers/char/tty_io.c
View File

@ -1204,53 +1204,38 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p)
sprintf(p, "%s%d", driver->name, index + driver->name_base);
}
/*
* find_tty() - find an existing tty, if any
* @driver: the driver for the tty
* @idx: the minor number
/**
* tty_driver_lookup_tty() - find an existing tty, if any
* @driver: the driver for the tty
* @idx: the minor number
*
* Return the tty, if found or ERR_PTR() otherwise.
* Return the tty, if found or ERR_PTR() otherwise.
*
* Locking: tty_mutex must be held. If tty is found, the mutex must
* be held until the 'fast-open' is also done.
* Locking: tty_mutex must be held. If tty is found, the mutex must
* be held until the 'fast-open' is also done. Will change once we
* have refcounting in the driver and per driver locking
*/
struct tty_struct *find_tty(struct tty_driver *driver, int idx)
struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, int idx)
{
struct tty_struct *tty;
/* check whether we're reopening an existing tty */
if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
tty = devpts_get_tty(idx);
/*
* If we don't have a tty here on a slave open, it's because
* the master already started the close process and there's
* no relation between devpts file and tty anymore.
*/
if (!tty && driver->subtype == PTY_TYPE_SLAVE)
return ERR_PTR(-EIO);
if (driver->ops->lookup)
return driver->ops->lookup(driver, idx);
/*
* tty is safe on because we are called with tty_mutex held
* and release_dev() won't change tty->count or tty->flags
* without grabbing tty_mutex.
*/
if (tty && driver->subtype == PTY_TYPE_MASTER)
tty = tty->link;
} else
tty = driver->ttys[idx];
return tty;
}
/*
* fast_tty_open() - fast re-open of an open tty
* @tty - the tty to open
/**
* tty_reopen() - fast re-open of an open tty
* @tty - the tty to open
*
* Return 0 on success, -errno on error.
* Return 0 on success, -errno on error.
*
* Locking: tty_mutex must be held from the time the tty was found
* till this open completes.
* Locking: tty_mutex must be held from the time the tty was found
* till this open completes.
*/
static int fast_tty_open(struct tty_struct *tty)
static int tty_reopen(struct tty_struct *tty)
{
struct tty_driver *driver = tty->driver;
@ -1271,9 +1256,7 @@ static int fast_tty_open(struct tty_struct *tty)
tty->count++;
tty->driver = driver; /* N.B. why do this every time?? */
/* FIXME */
if (!test_bit(TTY_LDISC, &tty->flags))
printk(KERN_ERR "fast_tty_open: no ldisc\n");
WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
return 0;
}
@ -1312,14 +1295,14 @@ int tty_init_dev(struct tty_driver *driver, int idx,
int retval = 0;
/* check whether we're reopening an existing tty */
tty = find_tty(driver, idx);
tty = tty_driver_lookup_tty(driver, idx);
if (IS_ERR(tty)) {
retval = PTR_ERR(tty);
goto end_init;
}
if (tty) {
retval = fast_tty_open(tty);
retval = tty_reopen(tty);
if (retval)
return retval;
*ret_tty = tty;
@ -1440,6 +1423,8 @@ 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;
@ -1466,9 +1451,8 @@ int tty_init_dev(struct tty_driver *driver, int idx,
if (retval)
goto release_mem_out;
success:
*ret_tty = tty;
*ret_tty = tty;
/* All paths come through here to release the mutex */
end_init:
return retval;

9
include/linux/tty_driver.h
View File

@ -7,6 +7,14 @@
* defined; unless noted otherwise, they are optional, and can be
* filled in with a null pointer.
*
* struct tty_struct * (*lookup)(struct tty_driver *self, int idx)
*
* Return the tty device corresponding to idx, NULL if there is not
* one currently in use and an ERR_PTR value on error. Called under
* tty_mutex (for now!)
*
* 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.
@ -203,6 +211,7 @@ struct tty_struct;
struct tty_driver;
struct tty_operations {
struct tty_struct * (*lookup)(struct tty_driver *driver, int idx);
int (*open)(struct tty_struct * tty, struct file * filp);
void (*close)(struct tty_struct * tty, struct file * filp);
void (*shutdown)(struct tty_struct *tty);