From 04831dc154df9b83c3e5fd54b18448da507871f7 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 4 Jun 2012 13:35:36 +0200 Subject: TTY: add ports array to tty_driver It will hold tty_port structures for all drivers which do not want to define tty->ops->install hook. We ignore PTY here because it wants 1 million lines and it installs tty_port in ->install anyway. Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- include/linux/tty_driver.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty_driver.h') diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 6e6dbb7447b6..04419c141b00 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -313,6 +313,7 @@ struct tty_driver { * Pointer to the tty data structures */ struct tty_struct **ttys; + struct tty_port **ports; struct ktermios **termios; void *driver_state; -- cgit v1.2.3 From 36b3c070d2346c890d690d71f6eab02f8c511137 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Tue, 17 Jul 2012 17:06:57 +0100 Subject: tty: Move the handling of the tty release logic Now that we don't have tty->termios tied to drivers->tty we can untangle the logic here. In addition we can push the removal logic out of the destructor path. At that point we can think about sorting out tty_port and console and all the other ugly hangovers. Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/pty.c | 12 ++------- drivers/tty/tty_io.c | 56 ++++++++++++++++++++--------------------- drivers/tty/vt/vt.c | 1 - drivers/usb/serial/usb-serial.c | 3 +-- include/linux/tty.h | 1 - include/linux/tty_driver.h | 11 +++----- 6 files changed, 34 insertions(+), 50 deletions(-) (limited to 'include/linux/tty_driver.h') diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index 5ad7ccc49f74..60c08ce83782 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -527,12 +527,6 @@ static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, return tty; } -static void pty_unix98_shutdown(struct tty_struct *tty) -{ - tty_driver_remove_tty(tty->driver, tty); - /* We have our own method as we don't use the tty index */ -} - /* We have no need to install and remove our tty objects as devpts does all the work for us */ @@ -558,9 +552,8 @@ static const struct tty_operations ptm_unix98_ops = { .unthrottle = pty_unthrottle, .set_termios = pty_set_termios, .ioctl = pty_unix98_ioctl, - .shutdown = pty_unix98_shutdown, - .cleanup = pty_cleanup, - .resize = pty_resize + .resize = pty_resize, + .cleanup = pty_cleanup }; static const struct tty_operations pty_unix98_ops = { @@ -575,7 +568,6 @@ 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, .cleanup = pty_cleanup, }; diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index cfd12da81218..be18d60ddf4c 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1249,16 +1249,16 @@ int tty_init_termios(struct tty_struct *tty) struct ktermios *tp; int idx = tty->index; - tp = tty->driver->termios[idx]; - if (tp == NULL) { - tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); - if (tp == NULL) - return -ENOMEM; - *tp = tty->driver->init_termios; - tty->driver->termios[idx] = tp; + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + tty->termios = tty->driver->init_termios; + else { + /* Check for lazy saved data */ + tp = tty->driver->termios[idx]; + if (tp != NULL) + tty->termios = *tp; + else + tty->termios = tty->driver->init_termios; } - tty->termios = *tp; - /* 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); @@ -1437,24 +1437,24 @@ void tty_free_termios(struct tty_struct *tty) { struct ktermios *tp; int idx = tty->index; - /* Kill this flag and push into drivers for locking etc */ - if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { - /* FIXME: Locking on ->termios array */ - tp = tty->driver->termios[idx]; - tty->driver->termios[idx] = NULL; - kfree(tp); + + /* If the port is going to reset then it has no termios to save */ + if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + return; + + /* Stash the termios data */ + tp = tty->driver->termios[idx]; + if (tp == NULL) { + tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); + if (tp == NULL) { + pr_warn("tty: no memory to save termios state.\n"); + return; + } } - else - *tty->driver->termios[idx] = tty->termios; + *tp = tty->termios; } EXPORT_SYMBOL(tty_free_termios); -void tty_shutdown(struct tty_struct *tty) -{ - tty_driver_remove_tty(tty->driver, tty); - tty_free_termios(tty); -} -EXPORT_SYMBOL(tty_shutdown); /** * release_one_tty - release tty structure memory @@ -1498,11 +1498,6 @@ static void queue_release_one_tty(struct kref *kref) { struct tty_struct *tty = container_of(kref, struct tty_struct, kref); - if (tty->ops->shutdown) - tty->ops->shutdown(tty); - else - tty_shutdown(tty); - /* The hangup queue is now free so we can reuse it rather than waste a chunk of memory for each port */ INIT_WORK(&tty->hangup_work, release_one_tty); @@ -1542,6 +1537,11 @@ static void release_tty(struct tty_struct *tty, int idx) /* This should always be true but check for the moment */ WARN_ON(tty->index != idx); + if (tty->ops->shutdown) + tty->ops->shutdown(tty); + tty_free_termios(tty); + tty_driver_remove_tty(tty->driver, tty); + if (tty->link) tty_kref_put(tty->link); tty_kref_put(tty); diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index dbceaeb2c3eb..e07ded30fc7f 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -2850,7 +2850,6 @@ static void con_shutdown(struct tty_struct *tty) console_lock(); vc->port.tty = NULL; console_unlock(); - tty_shutdown(tty); } static int default_italic_color = 2; // green (ASCII) diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 5fe21357b55c..aa4b0d775992 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -305,8 +305,7 @@ static void serial_close(struct tty_struct *tty, struct file *filp) * Do the resource freeing and refcount dropping for the port. * Avoid freeing the console. * - * Called asynchronously after the last tty kref is dropped, - * and the tty layer has already done the tty_shutdown(tty); + * Called asynchronously after the last tty kref is dropped. */ static void serial_cleanup(struct tty_struct *tty) { diff --git a/include/linux/tty.h b/include/linux/tty.h index d5e75ee0f4d1..a39e72325e78 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -423,7 +423,6 @@ extern void tty_unthrottle(struct tty_struct *tty); extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws); extern void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty); -extern void tty_shutdown(struct tty_struct *tty); extern void tty_free_termios(struct tty_struct *tty); extern int is_current_pgrp_orphaned(void); extern struct pid *tty_get_pgrp(struct tty_struct *tty); diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 04419c141b00..80e72dc564a5 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -45,14 +45,9 @@ * * void (*shutdown)(struct tty_struct * tty); * - * This routine is called synchronously when a particular tty device - * is closed for the last time freeing up the resources. - * Note that tty_shutdown() is not called if ops->shutdown is defined. - * This means one is responsible to take care of calling ops->remove (e.g. - * via tty_driver_remove_tty) and releasing tty->termios. - * Note that this hook may be called from *all* the contexts where one - * uses tty refcounting (e.g. tty_port_tty_get). - * + * This routine is called under the tty lock when a particular tty device + * is closed for the last time. It executes before the tty resources + * are freed so may execute while another function holds a tty kref. * * void (*cleanup)(struct tty_struct * tty); * -- cgit v1.2.3 From 7f0bc6a68ed93f3b4ad77b94df5ef32446c583e3 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Tue, 7 Aug 2012 21:47:42 +0200 Subject: TTY: pass flags to alloc_tty_driver We need to allow drivers that use neither tty_port_install nor tty_port_register_device to link a tty_port to a tty somehow. To avoid a race with open, this has to be performed before tty_register_device. But currently tty_driver->ports is allocated even in tty_register_device because we do not know whether this is the PTY driver. The PTY driver is special here due to an excessive count of lines it declares to handle. We cannot handle tty_ports there this way. To circumvent this, we start passing tty_driver flags to alloc_tty_driver already and we create tty_alloc_driver for this purpose. There we can allocate tty_driver->ports and do all the magic between tty_alloc_driver and tty_register_device. Later we will introduce tty_port_link_device function for that purpose. All drivers should eventually switch to this new tty driver allocation interface. Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 34 +++++++++++++++++++++++++--------- include/linux/tty_driver.h | 23 +++++++++++++++++++---- 2 files changed, 44 insertions(+), 13 deletions(-) (limited to 'include/linux/tty_driver.h') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 690224483fab..098a7c72b640 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3061,21 +3061,37 @@ void tty_unregister_device(struct tty_driver *driver, unsigned index) } EXPORT_SYMBOL(tty_unregister_device); -struct tty_driver *__alloc_tty_driver(int lines, struct module *owner) +/** + * __tty_alloc_driver -- allocate tty driver + * @lines: count of lines this driver can handle at most + * @owner: module which is repsonsible for this driver + * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags + * + * This should not be called directly, some of the provided macros should be + * used instead. Use IS_ERR and friends on @retval. + */ +struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, + unsigned long flags) { struct tty_driver *driver; + if (!lines) + return ERR_PTR(-EINVAL); + driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); - if (driver) { - kref_init(&driver->kref); - driver->magic = TTY_DRIVER_MAGIC; - driver->num = lines; - driver->owner = owner; - /* later we'll move allocation of tables here */ - } + if (!driver) + return ERR_PTR(-ENOMEM); + + kref_init(&driver->kref); + driver->magic = TTY_DRIVER_MAGIC; + driver->num = lines; + driver->owner = owner; + driver->flags = flags; + /* later we'll move allocation of tables here */ + return driver; } -EXPORT_SYMBOL(__alloc_tty_driver); +EXPORT_SYMBOL(__tty_alloc_driver); static void destruct_tty_driver(struct kref *kref) { diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 80e72dc564a5..3adc362f0bd2 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -296,11 +296,11 @@ struct tty_driver { int name_base; /* offset of printed name */ int major; /* major device number */ int minor_start; /* start of minor device number */ - int num; /* number of devices allocated */ + unsigned int num; /* number of devices allocated */ short type; /* type of tty driver */ short subtype; /* subtype of tty driver */ struct ktermios init_termios; /* Initial termios */ - int flags; /* tty driver flags */ + unsigned long flags; /* tty driver flags */ struct proc_dir_entry *proc_entry; /* /proc fs entry */ struct tty_driver *other; /* only used for the PTY driver */ @@ -322,7 +322,8 @@ struct tty_driver { extern struct list_head tty_drivers; -extern struct tty_driver *__alloc_tty_driver(int lines, struct module *owner); +extern struct tty_driver *__tty_alloc_driver(unsigned int lines, + struct module *owner, unsigned long flags); extern void put_tty_driver(struct tty_driver *driver); extern void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op); @@ -330,7 +331,21 @@ extern struct tty_driver *tty_find_polling_driver(char *name, int *line); extern void tty_driver_kref_put(struct tty_driver *driver); -#define alloc_tty_driver(lines) __alloc_tty_driver(lines, THIS_MODULE) +/* Use TTY_DRIVER_* flags below */ +#define tty_alloc_driver(lines, flags) \ + __tty_alloc_driver(lines, THIS_MODULE, flags) + +/* + * DEPRECATED Do not use this in new code, use tty_alloc_driver instead. + * (And change the return value checks.) + */ +static inline struct tty_driver *alloc_tty_driver(unsigned int lines) +{ + struct tty_driver *ret = tty_alloc_driver(lines, 0); + if (IS_ERR(ret)) + return NULL; + return ret; +} static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) { -- cgit v1.2.3 From 21aca2fa00259f781d228496631b61dbb4274e90 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 8 Aug 2012 22:26:41 +0200 Subject: TTY: pty, switch to tty_alloc_driver Switch to the new driver allocation interface, as this is one of the special call-sites. Here, we need TTY_DRIVER_DYNAMIC_ALLOC to not allocate tty_driver->ports, cdevs and potentially other structures because we reserve too many lines in pty. Instead, it provides the tty_port<->tty_struct link in tty->ops->install already. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/pty.c | 31 ++++++++++++++++++++----------- include/linux/tty_driver.h | 4 ++++ 2 files changed, 24 insertions(+), 11 deletions(-) (limited to 'include/linux/tty_driver.h') diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index d9ea9e2c9ec5..f5a27c66ff60 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -444,11 +444,17 @@ static void __init legacy_pty_init(void) if (legacy_count <= 0) return; - pty_driver = alloc_tty_driver(legacy_count); + pty_driver = tty_alloc_driver(legacy_count, + TTY_DRIVER_RESET_TERMIOS | + TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_ALLOC); if (!pty_driver) panic("Couldn't allocate pty driver"); - pty_slave_driver = alloc_tty_driver(legacy_count); + pty_slave_driver = tty_alloc_driver(legacy_count, + TTY_DRIVER_RESET_TERMIOS | + TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_ALLOC); if (!pty_slave_driver) panic("Couldn't allocate pty slave driver"); @@ -465,7 +471,6 @@ static void __init legacy_pty_init(void) pty_driver->init_termios.c_lflag = 0; pty_driver->init_termios.c_ispeed = 38400; pty_driver->init_termios.c_ospeed = 38400; - pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW; pty_driver->other = pty_slave_driver; tty_set_operations(pty_driver, &master_pty_ops_bsd); @@ -479,8 +484,6 @@ static void __init legacy_pty_init(void) pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; pty_slave_driver->init_termios.c_ispeed = 38400; pty_slave_driver->init_termios.c_ospeed = 38400; - pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS | - TTY_DRIVER_REAL_RAW; pty_slave_driver->other = pty_driver; tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); @@ -673,10 +676,20 @@ static struct file_operations ptmx_fops; static void __init unix98_pty_init(void) { - ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); + ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, + TTY_DRIVER_RESET_TERMIOS | + TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_DEV | + TTY_DRIVER_DEVPTS_MEM | + TTY_DRIVER_DYNAMIC_ALLOC); if (!ptm_driver) panic("Couldn't allocate Unix98 ptm driver"); - pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); + pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, + TTY_DRIVER_RESET_TERMIOS | + TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_DEV | + TTY_DRIVER_DEVPTS_MEM | + TTY_DRIVER_DYNAMIC_ALLOC); if (!pts_driver) panic("Couldn't allocate Unix98 pts driver"); @@ -693,8 +706,6 @@ static void __init unix98_pty_init(void) ptm_driver->init_termios.c_lflag = 0; ptm_driver->init_termios.c_ispeed = 38400; ptm_driver->init_termios.c_ospeed = 38400; - ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | - TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; ptm_driver->other = pts_driver; tty_set_operations(ptm_driver, &ptm_unix98_ops); @@ -708,8 +719,6 @@ static void __init unix98_pty_init(void) pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; pts_driver->init_termios.c_ispeed = 38400; pts_driver->init_termios.c_ospeed = 38400; - 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_unix98_ops); diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 3adc362f0bd2..1a85f003d646 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -391,6 +391,9 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) * the requested timeout to the caller instead of using a simple * on/off interface. * + * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are + * needed per line for this driver as it would waste memory. + * The driver will take care. */ #define TTY_DRIVER_INSTALLED 0x0001 #define TTY_DRIVER_RESET_TERMIOS 0x0002 @@ -398,6 +401,7 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) #define TTY_DRIVER_DYNAMIC_DEV 0x0008 #define TTY_DRIVER_DEVPTS_MEM 0x0010 #define TTY_DRIVER_HARDWARE_BREAK 0x0020 +#define TTY_DRIVER_DYNAMIC_ALLOC 0x0040 /* tty driver types */ #define TTY_DRIVER_TYPE_SYSTEM 0x0001 -- cgit v1.2.3 From 0019b4089ccef8148d8be83cc8adfc81a75b47d4 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 8 Aug 2012 22:26:43 +0200 Subject: TTY: add support for unnumbered device nodes This allows drivers like ttyprintk to avoid hacks to create an unnumbered node in /dev. It used to set TTY_DRIVER_DYNAMIC_DEV in flags and call device_create on its own. That is incorrect, because TTY_DRIVER_DYNAMIC_DEV may be set only if tty_register_device is called explicitly. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/char/ttyprintk.c | 17 ++++------------- drivers/tty/tty_io.c | 7 +++++-- include/linux/tty_driver.h | 6 ++++++ 3 files changed, 15 insertions(+), 15 deletions(-) (limited to 'include/linux/tty_driver.h') diff --git a/drivers/char/ttyprintk.c b/drivers/char/ttyprintk.c index be1c3fb186c1..9e6272f0b98c 100644 --- a/drivers/char/ttyprintk.c +++ b/drivers/char/ttyprintk.c @@ -178,13 +178,15 @@ static struct tty_driver *ttyprintk_driver; static int __init ttyprintk_init(void) { int ret = -ENOMEM; - void *rp; tty_port_init(&tpk_port.port); tpk_port.port.ops = &null_ops; mutex_init(&tpk_port.port_write_mutex); - ttyprintk_driver = alloc_tty_driver(1); + ttyprintk_driver = tty_alloc_driver(1, + TTY_DRIVER_RESET_TERMIOS | + TTY_DRIVER_REAL_RAW | + TTY_DRIVER_UNNUMBERED_NODE); if (!ttyprintk_driver) return ret; @@ -195,8 +197,6 @@ static int __init ttyprintk_init(void) ttyprintk_driver->type = TTY_DRIVER_TYPE_CONSOLE; ttyprintk_driver->init_termios = tty_std_termios; ttyprintk_driver->init_termios.c_oflag = OPOST | OCRNL | ONOCR | ONLRET; - ttyprintk_driver->flags = TTY_DRIVER_RESET_TERMIOS | - TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; tty_set_operations(ttyprintk_driver, &ttyprintk_ops); ret = tty_register_driver(ttyprintk_driver); @@ -205,15 +205,6 @@ static int __init ttyprintk_init(void) goto error; } - /* create our unnumbered device */ - rp = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 3), NULL, - ttyprintk_driver->name); - if (IS_ERR(rp)) { - printk(KERN_ERR "Couldn't create ttyprintk device\n"); - ret = PTR_ERR(rp); - goto error; - } - return 0; error: diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index a67609b9f21b..4d9898c2b641 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1216,7 +1216,10 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p) */ static void tty_line_name(struct tty_driver *driver, int index, char *p) { - sprintf(p, "%s%d", driver->name, index + driver->name_base); + if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE) + strcpy(p, driver->name); + else + sprintf(p, "%s%d", driver->name, index + driver->name_base); } /** @@ -3076,7 +3079,7 @@ struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, struct tty_driver *driver; int err; - if (!lines) + if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1)) return ERR_PTR(-EINVAL); driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 1a85f003d646..44e05b75d573 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -394,6 +394,11 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are * needed per line for this driver as it would waste memory. * The driver will take care. + * + * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In + * other words create /dev/ttyprintk and not /dev/ttyprintk0. + * Applicable only when a driver for a single tty device is + * being allocated. */ #define TTY_DRIVER_INSTALLED 0x0001 #define TTY_DRIVER_RESET_TERMIOS 0x0002 @@ -402,6 +407,7 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) #define TTY_DRIVER_DEVPTS_MEM 0x0010 #define TTY_DRIVER_HARDWARE_BREAK 0x0020 #define TTY_DRIVER_DYNAMIC_ALLOC 0x0040 +#define TTY_DRIVER_UNNUMBERED_NODE 0x0080 /* tty driver types */ #define TTY_DRIVER_TYPE_SYSTEM 0x0001 -- cgit v1.2.3 From 7e73eca6a7b2967423902a4543821bb97cbbe698 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 8 Aug 2012 22:26:44 +0200 Subject: TTY: move cdev_add to tty_register_device We need the /dev/ node not to be available before we call tty_register_device. Otherwise we might race with open and tty_struct->port might not be available at that time. This is not an issue now, but would be a problem after "TTY: use tty_port_register_device" is applied. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 48 +++++++++++++++++++++++++++++++++++++++------- include/linux/tty_driver.h | 2 +- 2 files changed, 42 insertions(+), 8 deletions(-) (limited to 'include/linux/tty_driver.h') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 4d9898c2b641..28c3e869ebba 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3006,6 +3006,15 @@ EXPORT_SYMBOL_GPL(tty_put_char); struct class *tty_class; +static int tty_cdev_add(struct tty_driver *driver, dev_t dev, + unsigned int index, unsigned int count) +{ + /* init here, since reused cdevs cause crashes */ + cdev_init(&driver->cdevs[index], &tty_fops); + driver->cdevs[index].owner = driver->owner; + return cdev_add(&driver->cdevs[index], dev, count); +} + /** * tty_register_device - register a tty device * @driver: the tty driver that describes the tty device @@ -3028,8 +3037,10 @@ struct class *tty_class; struct device *tty_register_device(struct tty_driver *driver, unsigned index, struct device *device) { + struct device *ret; char name[64]; dev_t dev = MKDEV(driver->major, driver->minor_start) + index; + bool cdev = false; if (index >= driver->num) { printk(KERN_ERR "Attempt to register invalid tty line number " @@ -3042,7 +3053,18 @@ struct device *tty_register_device(struct tty_driver *driver, unsigned index, else tty_line_name(driver, index, name); - return device_create(tty_class, device, dev, NULL, name); + if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { + int error = tty_cdev_add(driver, dev, index, 1); + if (error) + return ERR_PTR(error); + cdev = true; + } + + ret = device_create(tty_class, device, dev, NULL, name); + if (IS_ERR(ret) && cdev) + cdev_del(&driver->cdevs[index]); + + return ret; } EXPORT_SYMBOL(tty_register_device); @@ -3061,6 +3083,8 @@ void tty_unregister_device(struct tty_driver *driver, unsigned index) { device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); + if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) + cdev_del(&driver->cdevs[index]); } EXPORT_SYMBOL(tty_unregister_device); @@ -3077,6 +3101,7 @@ struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, unsigned long flags) { struct tty_driver *driver; + unsigned int cdevs = 1; int err; if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1)) @@ -3110,6 +3135,13 @@ struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, err = -ENOMEM; goto err_free_all; } + cdevs = lines; + } + + driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL); + if (!driver->cdevs) { + err = -ENOMEM; + goto err_free_all; } return driver; @@ -3144,8 +3176,10 @@ static void destruct_tty_driver(struct kref *kref) tty_unregister_device(driver, i); } proc_tty_unregister_driver(driver); - cdev_del(&driver->cdev); + if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) + cdev_del(&driver->cdevs[0]); } + kfree(driver->cdevs); kfree(driver->ports); kfree(driver->termios); kfree(driver->ttys); @@ -3195,11 +3229,11 @@ int tty_register_driver(struct tty_driver *driver) if (error < 0) goto err; - cdev_init(&driver->cdev, &tty_fops); - driver->cdev.owner = driver->owner; - error = cdev_add(&driver->cdev, dev, driver->num); - if (error) - goto err_unreg_char; + if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) { + error = tty_cdev_add(driver, dev, 0, driver->num); + if (error) + goto err_unreg_char; + } mutex_lock(&tty_mutex); list_add(&driver->tty_drivers, &tty_drivers); diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 44e05b75d573..dd976cfb6131 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -289,7 +289,7 @@ struct tty_operations { struct tty_driver { int magic; /* magic number for this structure */ struct kref kref; /* Reference management */ - struct cdev cdev; + struct cdev *cdevs; struct module *owner; const char *driver_name; const char *name; -- cgit v1.2.3