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| author | Olof Johansson <olof@lixom.net> | 2012-09-20 21:16:30 -0700 |
|---|---|---|
| committer | Olof Johansson <olof@lixom.net> | 2012-09-20 21:16:30 -0700 |
| commit | b74aae9a2074e1caa2e40bf119f3a633f77c94e4 (patch) | |
| tree | ba465514cff017a3213e65556674c68be5db29f6 /drivers/tty/tty_mutex.c | |
| parent | 5698bd757d55b1bb87edd1a9744ab09c142abfc2 (diff) | |
| parent | b97ba3ab4e8ec88164a47c98c91955e90ecd7c6a (diff) | |
| download | linux-b74aae9a2074e1caa2e40bf119f3a633f77c94e4.tar.gz linux-b74aae9a2074e1caa2e40bf119f3a633f77c94e4.tar.bz2 linux-b74aae9a2074e1caa2e40bf119f3a633f77c94e4.zip | |
Merge branch 'next/cleanup' into next/multiplatform
* next/cleanup: (358 commits)
ARM: tegra: harmony: fix ldo7 regulator-name
ARM: OMAP2+: Make omap4-keypad.h local
ARM: OMAP2+: Make l4_3xxx.h local
ARM: OMAP2+: Make l4_2xxx.h local
ARM: OMAP2+: Make l3_3xxx.h local
ARM: OMAP2+: Make l3_2xxx.h local
ARM: OMAP1: Move irda.h from plat to mach
ARM: OMAP2+: Make hdq1w.h local
ARM: OMAP2+: Make gpmc-smsc911x.h local
ARM: OMAP2+: Make gpmc-smc91x.h local
ARM: OMAP1: Move flash.h from plat to mach
ARM: OMAP2+: Make debug-devices.h local
ARM: OMAP1: Move board-voiceblue.h from plat to mach
ARM: OMAP1: Move board-sx1.h from plat to mach
ARM: OMAP2+: Make omap-wakeupgen.h local
ARM: OMAP2+: Make omap-secure.h local
ARM: OMAP2+: Make ctrl_module_wkup_44xx.h local
ARM: OMAP2+: Make ctrl_module_pad_wkup_44xx.h local
ARM: OMAP2+: Make ctrl_module_pad_core_44xx.h local
ARM: OMAP2+: Make ctrl_module_core_44xx.h local
...
Diffstat (limited to 'drivers/tty/tty_mutex.c')
| -rw-r--r-- | drivers/tty/tty_mutex.c | 71 |
1 files changed, 56 insertions, 15 deletions
diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 9ff986c32a21..67feac9e6ebb 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -4,29 +4,70 @@ #include <linux/semaphore.h> #include <linux/sched.h> -/* - * The 'big tty mutex' - * - * This mutex is taken and released by tty_lock() and tty_unlock(), - * replacing the older big kernel lock. - * It can no longer be taken recursively, and does not get - * released implicitly while sleeping. - * - * Don't use in new code. - */ -static DEFINE_MUTEX(big_tty_mutex); +/* Legacy tty mutex glue */ + +enum { + TTY_MUTEX_NORMAL, + TTY_MUTEX_NESTED, +}; /* * Getting the big tty mutex. */ -void __lockfunc tty_lock(void) + +static void __lockfunc tty_lock_nested(struct tty_struct *tty, + unsigned int subclass) { - mutex_lock(&big_tty_mutex); + if (tty->magic != TTY_MAGIC) { + printk(KERN_ERR "L Bad %p\n", tty); + WARN_ON(1); + return; + } + tty_kref_get(tty); + mutex_lock_nested(&tty->legacy_mutex, subclass); +} + +void __lockfunc tty_lock(struct tty_struct *tty) +{ + return tty_lock_nested(tty, TTY_MUTEX_NORMAL); } EXPORT_SYMBOL(tty_lock); -void __lockfunc tty_unlock(void) +void __lockfunc tty_unlock(struct tty_struct *tty) { - mutex_unlock(&big_tty_mutex); + if (tty->magic != TTY_MAGIC) { + printk(KERN_ERR "U Bad %p\n", tty); + WARN_ON(1); + return; + } + mutex_unlock(&tty->legacy_mutex); + tty_kref_put(tty); } EXPORT_SYMBOL(tty_unlock); + +/* + * Getting the big tty mutex for a pair of ttys with lock ordering + * On a non pty/tty pair tty2 can be NULL which is just fine. + */ +void __lockfunc tty_lock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + if (tty < tty2) { + tty_lock(tty); + tty_lock_nested(tty2, TTY_MUTEX_NESTED); + } else { + if (tty2 && tty2 != tty) + tty_lock(tty2); + tty_lock_nested(tty, TTY_MUTEX_NESTED); + } +} +EXPORT_SYMBOL(tty_lock_pair); + +void __lockfunc tty_unlock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + tty_unlock(tty); + if (tty2 && tty2 != tty) + tty_unlock(tty2); +} +EXPORT_SYMBOL(tty_unlock_pair); |