lkml.org 
[lkml]   [2019]   [Apr]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v4 04/16] locking/rwsem: Implement a new locking scheme
On Sat, Apr 13, 2019 at 01:22:47PM -0400, Waiman Long wrote:
> +#define RWSEM_COUNT_LOCKED(c) ((c) & RWSEM_LOCK_MASK)

The above doesn't seem to make it more readable or shorter.

--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -192,7 +192,7 @@ static inline bool rwsem_try_write_lock(
{
long new;

- if (RWSEM_COUNT_LOCKED(count))
+ if (count & RWSEM_LOCK_MASK)
return false;

new = count + RWSEM_WRITER_LOCKED -
@@ -214,7 +214,7 @@ static inline bool rwsem_try_write_lock_
{
long count = atomic_long_read(&sem->count);

- while (!RWSEM_COUNT_LOCKED(count)) {
+ while (!(count & RWSEM_LOCK_MASK)) {
if (atomic_long_try_cmpxchg_acquire(&sem->count, &count,
count + RWSEM_WRITER_LOCKED)) {
rwsem_set_owner(sem);
@@ -393,7 +393,7 @@ __rwsem_down_read_failed_common(struct r
* If there are no writers and we are first in the queue,
* wake our own waiter to join the existing active readers !
*/
- if (!RWSEM_COUNT_LOCKED(count) ||
+ if (!(count & RWSEM_LOCK_MASK) ||
(!(count & RWSEM_WRITER_MASK) && (adjustment & RWSEM_FLAG_WAITERS)))
__rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);

@@ -522,7 +522,7 @@ __rwsem_down_write_failed_common(struct
lockevent_inc(rwsem_sleep_writer);
set_current_state(state);
count = atomic_long_read(&sem->count);
- } while (RWSEM_COUNT_LOCKED(count));
+ } while (count & RWSEM_LOCK_MASK);

raw_spin_lock_irq(&sem->wait_lock);
}
\
 
 \ /
  Last update: 2019-04-16 15:23    [W:0.489 / U:0.912 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site