diff options
| author |   Peter Zijlstra <peterz@infradead.org> | 2020-02-04 09:34:37 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2020-02-11 13:10:57 +0100 |
| commit | bcba67cd806800fa8e973ac49dbc7d2d8fb3e55e (patch) | |
| tree | 3d6fe168cd5bccb14aaca011a89164534b1123ef /kernel/locking/rwsem.c | |
| parent | locking/percpu-rwsem: Remove the embedded rwsem (diff) | |
| download | linux-dev-bcba67cd806800fa8e973ac49dbc7d2d8fb3e55e.tar.xz linux-dev-bcba67cd806800fa8e973ac49dbc7d2d8fb3e55e.zip | |
locking/rwsem: Remove RWSEM_OWNER_UNKNOWN
Remove the now unused RWSEM_OWNER_UNKNOWN hack. This hack breaks
PREEMPT_RT and getting rid of it was the entire motivation for
re-writing the percpu rwsem.
The biggest problem is that it is fundamentally incompatible with any
form of Priority Inheritance, any exclusively held lock must have a
distinct owner.
Requested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lkml.kernel.org/r/20200204092228.GP14946@hirez.programming.kicks-ass.net
Diffstat (limited to 'kernel/locking/rwsem.c')
| -rw-r--r-- | kernel/locking/rwsem.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 81c0d75d5dab..e6f437bafb23 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -659,8 +659,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem, unsigned long flags; bool ret = true; - BUILD_BUG_ON(!(RWSEM_OWNER_UNKNOWN & RWSEM_NONSPINNABLE)); - if (need_resched()) { lockevent_inc(rwsem_opt_fail); return false; |