diff options
author | Olof Johansson <olof@lixom.net> | 2012-09-20 13:19:32 -0700 |
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committer | Olof Johansson <olof@lixom.net> | 2012-09-20 13:22:20 -0700 |
commit | 2843c7d2c03da38dfb14102254d0c767d2483349 (patch) | |
tree | 8698671fd889ed9d6237cf9ea093e8bb1fc999b3 /drivers/tty/tty_mutex.c | |
parent | 084cfebc03ede864835594181210b501aa9f1933 (diff) | |
parent | 6bfc82ff589a00e5fbc12b958c649d703d273c86 (diff) |
Merge tag 'omap-devel-dt-merged-for-v3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into next/dt
Device tree related changes for omaps.
Note that this branch is based on omap-cleanup-sparseirq-for-v3.7
to avoid merge conflicts with the sparseirq changes for gpio-twl4030
driver.
* tag 'omap-devel-dt-merged-for-v3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
arm/dts: Mux uart pins for omap4-sdp
ARM: OMAP2+: select PINCTRL in Kconfig
arm/dts: Add pinctrl driver entries for omap2/3/4
arm/dts: Add omap36xx.dtsi file and rename omap3-beagle to omap3-beagle-xm
ARM: dts: omap3-overo: Add support for the blue LED
Documentation: dt: Update the OMAP documentation with Overo/Toby
ARM: dts: OMAP3: Add support for Gumstix Overo with Tobi expansion board
ARM: dts: OMAP4: Add reg and interrupts for every nodes
ARM: dts: AM33XX: Specify reg and interrupt property for all nodes
ARM: dts: AM33XX: Convert all hex numbers to lower-case
ARM: dts: omap3-beagle: Enable audio support
ARM: dts: omap5: Add McPDM and DMIC section to the dtsi file
ARM: dts: omap5: Add McBSP entries
ARM: dts: omap4: Add reg-names for McPDM and DMIC
ARM: dts: omap4: Add McBSP entries
ARM: dts: omap3: Add McBSP entries
ARM: dts: omap2420-h4: Include omap2420.dtsi file instead the common omap2
ARM: dts: omap2: Add McBSP entries for OMAP2420 and OMAP2430 SoC
ARM: dts: omap3-beagle: Add heartbeat and mmc LEDs support
ARM: dts: omap3: Add gpio-twl4030 properties for BeagleBoard and omap3-EVM
...
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); |