From 4f73bc4dd3e8563ef4109f293a092820dff66d92 Mon Sep 17 00:00:00 2001 From: Joe Millenbach Date: Thu, 17 Jan 2013 22:44:22 -0800 Subject: tty: Added a CONFIG_TTY option to allow removal of TTY The option allows you to remove TTY and compile without errors. This saves space on systems that won't support TTY interfaces anyway. bloat-o-meter output is below. The bulk of this patch consists of Kconfig changes adding "depends on TTY" to various serial devices and similar drivers that require the TTY layer. Ideally, these dependencies would occur on a common intermediate symbol such as SERIO, but most drivers "select SERIO" rather than "depends on SERIO", and "select" does not respect dependencies. bloat-o-meter output comparing our previous minimal to new minimal by removing TTY. The list is filtered to not show removed entries with awk '$3 != "-"' as the list was very long. add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350) function old new delta chr_dev_init 166 170 +4 allow_signal 80 82 +2 static.__warned 143 142 -1 disallow_signal 63 62 -1 __set_special_pids 95 94 -1 unregister_console 126 121 -5 start_kernel 546 541 -5 register_console 593 588 -5 copy_from_user 45 40 -5 sys_setsid 128 120 -8 sys_vhangup 32 19 -13 do_exit 1543 1526 -17 bitmap_zero 60 40 -20 arch_local_irq_save 137 117 -20 release_task 674 652 -22 static.spin_unlock_irqrestore 308 260 -48 Signed-off-by: Joe Millenbach Reviewed-by: Jamey Sharp Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman --- include/linux/console.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/console.h') diff --git a/include/linux/console.h b/include/linux/console.h index dedb082fe50f..3b709da1786e 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -157,7 +157,12 @@ extern int is_console_locked(void); extern int braille_register_console(struct console *, int index, char *console_options, char *braille_options); extern int braille_unregister_console(struct console *); +#ifdef CONFIG_TTY extern void console_sysfs_notify(void); +#else +static inline void console_sysfs_notify(void) +{ } +#endif extern bool console_suspend_enabled; /* Suspend and resume console messages over PM events */ -- cgit v1.2.3 From 50e244cc793d511b86adea24972f3a7264cae114 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Fri, 25 Jan 2013 10:28:15 +1000 Subject: fb: rework locking to fix lock ordering on takeover Adjust the console layer to allow a take over call where the caller already holds the locks. Make the fb layer lock in order. This is partly a band aid, the fb layer is terminally confused about the locking rules it uses for its notifiers it seems. [akpm@linux-foundation.org: remove stray non-ascii char, tidy comment] [akpm@linux-foundation.org: export do_take_over_console()] [airlied: cleanup another non-ascii char] Signed-off-by: Alan Cox Cc: Florian Tobias Schandinat Cc: Stephen Rothwell Cc: Jiri Kosina Cc: stable Tested-by: Sedat Dilek Reviewed-by: Daniel Vetter Signed-off-by: Andrew Morton Signed-off-by: Dave Airlie --- drivers/tty/vt/vt.c | 93 ++++++++++++++++++++++++++++++++----------- drivers/video/console/fbcon.c | 29 +++++++++++++- drivers/video/fbmem.c | 5 +-- drivers/video/fbsysfs.c | 3 ++ include/linux/console.h | 1 + 5 files changed, 104 insertions(+), 27 deletions(-) (limited to 'include/linux/console.h') diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 8fd89687d068..c076af0b300b 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -2987,7 +2987,7 @@ int __init vty_init(const struct file_operations *console_fops) static struct class *vtconsole_class; -static int bind_con_driver(const struct consw *csw, int first, int last, +static int do_bind_con_driver(const struct consw *csw, int first, int last, int deflt) { struct module *owner = csw->owner; @@ -2998,7 +2998,7 @@ static int bind_con_driver(const struct consw *csw, int first, int last, if (!try_module_get(owner)) return -ENODEV; - console_lock(); + WARN_CONSOLE_UNLOCKED(); /* check if driver is registered */ for (i = 0; i < MAX_NR_CON_DRIVER; i++) { @@ -3083,11 +3083,22 @@ static int bind_con_driver(const struct consw *csw, int first, int last, retval = 0; err: - console_unlock(); module_put(owner); return retval; }; + +static int bind_con_driver(const struct consw *csw, int first, int last, + int deflt) +{ + int ret; + + console_lock(); + ret = do_bind_con_driver(csw, first, last, deflt); + console_unlock(); + return ret; +} + #ifdef CONFIG_VT_HW_CONSOLE_BINDING static int con_is_graphics(const struct consw *csw, int first, int last) { @@ -3199,9 +3210,9 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt) if (!con_is_bound(csw)) con_driver->flag &= ~CON_DRIVER_FLAG_INIT; - console_unlock(); /* ignore return value, binding should not fail */ - bind_con_driver(defcsw, first, last, deflt); + do_bind_con_driver(defcsw, first, last, deflt); + console_unlock(); err: module_put(owner); return retval; @@ -3492,28 +3503,18 @@ int con_debug_leave(void) } EXPORT_SYMBOL_GPL(con_debug_leave); -/** - * register_con_driver - register console driver to console layer - * @csw: console driver - * @first: the first console to take over, minimum value is 0 - * @last: the last console to take over, maximum value is MAX_NR_CONSOLES -1 - * - * DESCRIPTION: This function registers a console driver which can later - * bind to a range of consoles specified by @first and @last. It will - * also initialize the console driver by calling con_startup(). - */ -int register_con_driver(const struct consw *csw, int first, int last) +static int do_register_con_driver(const struct consw *csw, int first, int last) { struct module *owner = csw->owner; struct con_driver *con_driver; const char *desc; int i, retval = 0; + WARN_CONSOLE_UNLOCKED(); + if (!try_module_get(owner)) return -ENODEV; - console_lock(); - for (i = 0; i < MAX_NR_CON_DRIVER; i++) { con_driver = ®istered_con_driver[i]; @@ -3566,10 +3567,29 @@ int register_con_driver(const struct consw *csw, int first, int last) } err: - console_unlock(); module_put(owner); return retval; } + +/** + * register_con_driver - register console driver to console layer + * @csw: console driver + * @first: the first console to take over, minimum value is 0 + * @last: the last console to take over, maximum value is MAX_NR_CONSOLES -1 + * + * DESCRIPTION: This function registers a console driver which can later + * bind to a range of consoles specified by @first and @last. It will + * also initialize the console driver by calling con_startup(). + */ +int register_con_driver(const struct consw *csw, int first, int last) +{ + int retval; + + console_lock(); + retval = do_register_con_driver(csw, first, last); + console_unlock(); + return retval; +} EXPORT_SYMBOL(register_con_driver); /** @@ -3623,17 +3643,44 @@ EXPORT_SYMBOL(unregister_con_driver); * when a driver wants to take over some existing consoles * and become default driver for newly opened ones. * - * take_over_console is basically a register followed by unbind + * take_over_console is basically a register followed by unbind + */ +int do_take_over_console(const struct consw *csw, int first, int last, int deflt) +{ + int err; + + err = do_register_con_driver(csw, first, last); + /* + * If we get an busy error we still want to bind the console driver + * and return success, as we may have unbound the console driver + * but not unregistered it. + */ + if (err == -EBUSY) + err = 0; + if (!err) + do_bind_con_driver(csw, first, last, deflt); + + return err; +} +EXPORT_SYMBOL_GPL(do_take_over_console); + +/* + * If we support more console drivers, this function is used + * when a driver wants to take over some existing consoles + * and become default driver for newly opened ones. + * + * take_over_console is basically a register followed by unbind */ int take_over_console(const struct consw *csw, int first, int last, int deflt) { int err; err = register_con_driver(csw, first, last); - /* if we get an busy error we still want to bind the console driver + /* + * If we get an busy error we still want to bind the console driver * and return success, as we may have unbound the console driver -  * but not unregistered it. - */ + * but not unregistered it. + */ if (err == -EBUSY) err = 0; if (!err) diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index fdefa8fd72c4..4bd7820cf4d0 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -529,6 +529,33 @@ static int search_for_mapped_con(void) return retval; } +static int do_fbcon_takeover(int show_logo) +{ + int err, i; + + if (!num_registered_fb) + return -ENODEV; + + if (!show_logo) + logo_shown = FBCON_LOGO_DONTSHOW; + + for (i = first_fb_vc; i <= last_fb_vc; i++) + con2fb_map[i] = info_idx; + + err = do_take_over_console(&fb_con, first_fb_vc, last_fb_vc, + fbcon_is_default); + + if (err) { + for (i = first_fb_vc; i <= last_fb_vc; i++) + con2fb_map[i] = -1; + info_idx = -1; + } else { + fbcon_has_console_bind = 1; + } + + return err; +} + static int fbcon_takeover(int show_logo) { int err, i; @@ -3115,7 +3142,7 @@ static int fbcon_fb_registered(struct fb_info *info) } if (info_idx != -1) - ret = fbcon_takeover(1); + ret = do_fbcon_takeover(1); } else { for (i = first_fb_vc; i <= last_fb_vc; i++) { if (con2fb_map_boot[i] == idx) diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c index 3ff0105a496a..d8d9831b3fdb 100644 --- a/drivers/video/fbmem.c +++ b/drivers/video/fbmem.c @@ -1650,7 +1650,9 @@ static int do_register_framebuffer(struct fb_info *fb_info) event.info = fb_info; if (!lock_fb_info(fb_info)) return -ENODEV; + console_lock(); fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event); + console_unlock(); unlock_fb_info(fb_info); return 0; } @@ -1853,11 +1855,8 @@ int fb_new_modelist(struct fb_info *info) err = 1; if (!list_empty(&info->modelist)) { - if (!lock_fb_info(info)) - return -ENODEV; event.info = info; err = fb_notifier_call_chain(FB_EVENT_NEW_MODELIST, &event); - unlock_fb_info(info); } return err; diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c index a55e3669d135..ef476b02fbe5 100644 --- a/drivers/video/fbsysfs.c +++ b/drivers/video/fbsysfs.c @@ -177,6 +177,8 @@ static ssize_t store_modes(struct device *device, if (i * sizeof(struct fb_videomode) != count) return -EINVAL; + if (!lock_fb_info(fb_info)) + return -ENODEV; console_lock(); list_splice(&fb_info->modelist, &old_list); fb_videomode_to_modelist((const struct fb_videomode *)buf, i, @@ -188,6 +190,7 @@ static ssize_t store_modes(struct device *device, fb_destroy_modelist(&old_list); console_unlock(); + unlock_fb_info(fb_info); return 0; } diff --git a/include/linux/console.h b/include/linux/console.h index dedb082fe50f..4ef4307dfb82 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -78,6 +78,7 @@ int con_is_bound(const struct consw *csw); int register_con_driver(const struct consw *csw, int first, int last); int unregister_con_driver(const struct consw *csw); int take_over_console(const struct consw *sw, int first, int last, int deflt); +int do_take_over_console(const struct consw *sw, int first, int last, int deflt); void give_up_console(const struct consw *sw); #ifdef CONFIG_HW_CONSOLE int con_debug_enter(struct vc_data *vc); -- cgit v1.2.3 From e93a9a868792ad71cdd09d75e5a02d8067473c4e Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 25 Jan 2013 10:28:18 +1000 Subject: fb: Yet another band-aid for fixing lockdep mess I've still got lockdep warnings even after Alan's patch, and it seems that yet more band aids are required to paper over similar paths for unbind_con_driver() and unregister_con_driver(). After this hack, lockdep warnings are finally gone. Signed-off-by: Takashi Iwai Cc: Alan Cox Cc: Florian Tobias Schandinat Cc: Jiri Kosina Cc: stable Tested-by: Sedat Dilek Signed-off-by: Andrew Morton Signed-off-by: Dave Airlie --- drivers/tty/vt/vt.c | 43 ++++++++++++++++++++++++++++--------------- drivers/video/console/fbcon.c | 4 ++-- drivers/video/fbmem.c | 4 ++++ include/linux/console.h | 1 + include/linux/vt_kern.h | 2 ++ 5 files changed, 37 insertions(+), 17 deletions(-) (limited to 'include/linux/console.h') diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index c076af0b300b..457c41fe7eb9 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -3134,6 +3134,18 @@ static int con_is_graphics(const struct consw *csw, int first, int last) * or 0 on success. */ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt) +{ + int retval; + + console_lock(); + retval = do_unbind_con_driver(csw, first, last, deflt); + console_unlock(); + return retval; +} +EXPORT_SYMBOL(unbind_con_driver); + +/* unlocked version of unbind_con_driver() */ +int do_unbind_con_driver(const struct consw *csw, int first, int last, int deflt) { struct module *owner = csw->owner; const struct consw *defcsw = NULL; @@ -3143,7 +3155,7 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt) if (!try_module_get(owner)) return -ENODEV; - console_lock(); + WARN_CONSOLE_UNLOCKED(); /* check if driver is registered and if it is unbindable */ for (i = 0; i < MAX_NR_CON_DRIVER; i++) { @@ -3156,10 +3168,8 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt) } } - if (retval) { - console_unlock(); + if (retval) goto err; - } retval = -ENODEV; @@ -3175,15 +3185,11 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt) } } - if (retval) { - console_unlock(); + if (retval) goto err; - } - if (!con_is_bound(csw)) { - console_unlock(); + if (!con_is_bound(csw)) goto err; - } first = max(first, con_driver->first); last = min(last, con_driver->last); @@ -3212,13 +3218,12 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt) /* ignore return value, binding should not fail */ do_bind_con_driver(defcsw, first, last, deflt); - console_unlock(); err: module_put(owner); return retval; } -EXPORT_SYMBOL(unbind_con_driver); +EXPORT_SYMBOL_GPL(do_unbind_con_driver); static int vt_bind(struct con_driver *con) { @@ -3605,9 +3610,18 @@ EXPORT_SYMBOL(register_con_driver); */ int unregister_con_driver(const struct consw *csw) { - int i, retval = -ENODEV; + int retval; console_lock(); + retval = do_unregister_con_driver(csw); + console_unlock(); + return retval; +} +EXPORT_SYMBOL(unregister_con_driver); + +int do_unregister_con_driver(const struct consw *csw) +{ + int i, retval = -ENODEV; /* cannot unregister a bound driver */ if (con_is_bound(csw)) @@ -3633,10 +3647,9 @@ int unregister_con_driver(const struct consw *csw) } } err: - console_unlock(); return retval; } -EXPORT_SYMBOL(unregister_con_driver); +EXPORT_SYMBOL_GPL(do_unregister_con_driver); /* * If we support more console drivers, this function is used diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index 4bd7820cf4d0..2aef9cac4d18 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -3004,7 +3004,7 @@ static int fbcon_unbind(void) { int ret; - ret = unbind_con_driver(&fb_con, first_fb_vc, last_fb_vc, + ret = do_unbind_con_driver(&fb_con, first_fb_vc, last_fb_vc, fbcon_is_default); if (!ret) @@ -3077,7 +3077,7 @@ static int fbcon_fb_unregistered(struct fb_info *info) primary_device = -1; if (!num_registered_fb) - unregister_con_driver(&fb_con); + do_unregister_con_driver(&fb_con); return 0; } diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c index d8d9831b3fdb..070b9a13d892 100644 --- a/drivers/video/fbmem.c +++ b/drivers/video/fbmem.c @@ -1668,8 +1668,10 @@ static int do_unregister_framebuffer(struct fb_info *fb_info) if (!lock_fb_info(fb_info)) return -ENODEV; + console_lock(); event.info = fb_info; ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event); + console_unlock(); unlock_fb_info(fb_info); if (ret) @@ -1684,7 +1686,9 @@ static int do_unregister_framebuffer(struct fb_info *fb_info) num_registered_fb--; fb_cleanup_device(fb_info); event.info = fb_info; + console_lock(); fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event); + console_unlock(); /* this may free fb info */ put_fb_info(fb_info); diff --git a/include/linux/console.h b/include/linux/console.h index 4ef4307dfb82..47b858cffc47 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -77,6 +77,7 @@ extern const struct consw prom_con; /* SPARC PROM console */ int con_is_bound(const struct consw *csw); int register_con_driver(const struct consw *csw, int first, int last); int unregister_con_driver(const struct consw *csw); +int do_unregister_con_driver(const struct consw *csw); int take_over_console(const struct consw *sw, int first, int last, int deflt); int do_take_over_console(const struct consw *sw, int first, int last, int deflt); void give_up_console(const struct consw *sw); diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h index 50ae7d0c279e..dbbc6bfee71f 100644 --- a/include/linux/vt_kern.h +++ b/include/linux/vt_kern.h @@ -130,6 +130,8 @@ void vt_event_post(unsigned int event, unsigned int old, unsigned int new); int vt_waitactive(int n); void change_console(struct vc_data *new_vc); void reset_vc(struct vc_data *vc); +extern int do_unbind_con_driver(const struct consw *csw, int first, int last, + int deflt); extern int unbind_con_driver(const struct consw *csw, int first, int last, int deflt); int vty_init(const struct file_operations *console_fops); -- cgit v1.2.3