xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

tty: replace BKL with a new tty_lock

Browse Source 
As a preparation for replacing the big kernel lock
in the TTY layer, wrap all the callers in new
macros tty_lock, tty_lock_nested and tty_unlock.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Arnd Bergmann
2010-06-01 22:53:01 +02:00
committed by Greg Kroah-Hartman
parent 3f582b8c11
commit ec79d6056d
17 changed files with 161 additions and 115 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
include/linux/tty.h
View File

@@ -13,6 +13,7 @@
#include <linux/tty_driver.h>
#include <linux/tty_ldisc.h>
#include <linux/mutex.h>
#include <linux/smp_lock.h>
#include <asm/system.h>
@@ -576,5 +577,35 @@ extern int vt_ioctl(struct tty_struct *tty, struct file *file,
extern long vt_compat_ioctl(struct tty_struct *tty, struct file * file,
unsigned int cmd, unsigned long arg);
/* functions for preparation of BKL removal */
/*
* tty_lock_nested get the tty_lock while potentially holding it
*
* The Big TTY Mutex is a recursive lock, meaning you can take it
* from a thread that is already holding it.
* This is bad for a number of reasons, so tty_lock_nested should
* really be used as rarely as possible. If a code location can
* be shown to never get called with this held already, it should
* use tty_lock() instead.
*/
static inline void __lockfunc tty_lock_nested(void) __acquires(kernel_lock)
{
lock_kernel();
}
static inline void tty_lock(void) __acquires(kernel_lock)
{
#ifdef CONFIG_LOCK_KERNEL
/* kernel_locked is 1 for !CONFIG_LOCK_KERNEL */
WARN_ON(kernel_locked());
#endif
lock_kernel();
}
static inline void tty_unlock(void) __releases(kernel_lock)
{
unlock_kernel();
}
#define tty_locked() (kernel_locked())
#endif /* __KERNEL__ */
#endif