diff options
| author | Davidlohr Bueso <dave@stgolabs.net> | 2017-01-03 13:43:12 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-01-14 11:14:13 +0100 |
| commit | 5376f2e722026e91cb46384bda8d8b3e9f88217c (patch) | |
| tree | c3f73f7179ff9e118e73068923119562689f31ac /drivers/tty | |
| parent | 0039962a1473f07fd5c8355bd8264be1eb87eb3e (diff) | |
drivers/tty: Compute 'current' directly
This patch effectively replaces the tsk pointer dereference
(which is obviously == current), to directly use get_current()
macro. This is to make the removal of setting foreign task
states smoother and painfully obvious. Performance win on some
archs such as x86-64 and ppc64 -- arm64 is no longer an issue.
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-3-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/tty_ldsem.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/drivers/tty/tty_ldsem.c b/drivers/tty/tty_ldsem.c index 1bf8ed13f827..3e6722954f29 100644 --- a/drivers/tty/tty_ldsem.c +++ b/drivers/tty/tty_ldsem.c @@ -200,7 +200,6 @@ static struct ld_semaphore __sched * down_read_failed(struct ld_semaphore *sem, long count, long timeout) { struct ldsem_waiter waiter; - struct task_struct *tsk = current; long adjust = -LDSEM_ACTIVE_BIAS + LDSEM_WAIT_BIAS; /* set up my own style of waitqueue */ @@ -221,8 +220,8 @@ down_read_failed(struct ld_semaphore *sem, long count, long timeout) list_add_tail(&waiter.list, &sem->read_wait); sem->wait_readers++; - waiter.task = tsk; - get_task_struct(tsk); + waiter.task = current; + get_task_struct(current); /* if there are no active locks, wake the new lock owner(s) */ if ((count & LDSEM_ACTIVE_MASK) == 0) @@ -232,7 +231,7 @@ down_read_failed(struct ld_semaphore *sem, long count, long timeout) /* wait to be given the lock */ for (;;) { - set_task_state(tsk, TASK_UNINTERRUPTIBLE); + set_task_state(current, TASK_UNINTERRUPTIBLE); if (!waiter.task) break; @@ -241,7 +240,7 @@ down_read_failed(struct ld_semaphore *sem, long count, long timeout) timeout = schedule_timeout(timeout); } - __set_task_state(tsk, TASK_RUNNING); + __set_task_state(current, TASK_RUNNING); if (!timeout) { /* lock timed out but check if this task was just @@ -268,7 +267,6 @@ static struct ld_semaphore __sched * down_write_failed(struct ld_semaphore *sem, long count, long timeout) { struct ldsem_waiter waiter; - struct task_struct *tsk = current; long adjust = -LDSEM_ACTIVE_BIAS; int locked = 0; @@ -289,16 +287,16 @@ down_write_failed(struct ld_semaphore *sem, long count, long timeout) list_add_tail(&waiter.list, &sem->write_wait); - waiter.task = tsk; + waiter.task = current; - set_task_state(tsk, TASK_UNINTERRUPTIBLE); + set_task_state(current, TASK_UNINTERRUPTIBLE); for (;;) { if (!timeout) break; raw_spin_unlock_irq(&sem->wait_lock); timeout = schedule_timeout(timeout); raw_spin_lock_irq(&sem->wait_lock); - set_task_state(tsk, TASK_UNINTERRUPTIBLE); + set_task_state(current, TASK_UNINTERRUPTIBLE); locked = writer_trylock(sem); if (locked) break; @@ -309,7 +307,7 @@ down_write_failed(struct ld_semaphore *sem, long count, long timeout) list_del(&waiter.list); raw_spin_unlock_irq(&sem->wait_lock); - __set_task_state(tsk, TASK_RUNNING); + __set_task_state(current, TASK_RUNNING); /* lock wait may have timed out */ if (!locked) |