diff options
author | David Woodhouse <David.Woodhouse@intel.com> | 2012-10-09 15:03:21 +0100 |
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committer | David Woodhouse <David.Woodhouse@intel.com> | 2012-10-09 15:04:25 +0100 |
commit | ffe315012510165ce82e4dd4767f0a5dba9edbf7 (patch) | |
tree | f601cd980af9d0ced5ca9aedecef4fa0d2ca0e15 /drivers/tty/tty_mutex.c | |
parent | e2d3a35ee427aaba99b6c68a56609ce276c51270 (diff) | |
parent | 4a8e43feeac7996b8de2d5b2823e316917493df4 (diff) |
Merge tag 'disintegrate-mtd-20121009' of git://git.infradead.org/users/dhowells/linux-headers
UAPI Disintegration 2012-10-09
Conflicts:
MAINTAINERS
arch/arm/configs/bcmring_defconfig
arch/arm/mach-imx/clk-imx51-imx53.c
drivers/mtd/nand/Kconfig
drivers/mtd/nand/bcm_umi_nand.c
drivers/mtd/nand/nand_bcm_umi.h
drivers/mtd/nand/orion_nand.c
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 9ff986c32a2..67feac9e6eb 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); |