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authorPeter Zijlstra <peterz@infradead.org>2020-02-04 09:34:37 +0100
committerIngo Molnar <mingo@kernel.org>2020-02-11 13:10:57 +0100
commitbcba67cd806800fa8e973ac49dbc7d2d8fb3e55e (patch)
tree3d6fe168cd5bccb14aaca011a89164534b1123ef /kernel/locking
parent7f26482a872c36b2ee87ea95b9dcd96e3d5805df (diff)
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')
-rw-r--r--kernel/locking/rwsem.c2
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;