Merge tag 'locking-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "The biggest change to core locking facilities in this cycle is the
  introduction of local_lock_t - this primitive comes from the -rt
  project and identifies CPU-local locking dependencies normally handled
  opaquely beind preempt_disable() or local_irq_save/disable() critical
  sections.

  The generated code on mainline kernels doesn't change as a result, but
  still there are benefits: improved debugging and better documentation
  of data structure accesses.

  The new local_lock_t primitives are introduced and then utilized in a
  couple of kernel subsystems. No change in functionality is intended.

  There's also other smaller changes and cleanups"

* tag 'locking-core-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  zram: Use local lock to protect per-CPU data
  zram: Allocate struct zcomp_strm as per-CPU memory
  connector/cn_proc: Protect send_msg() with a local lock
  squashfs: Make use of local lock in multi_cpu decompressor
  mm/swap: Use local_lock for protection
  radix-tree: Use local_lock for protection
  locking: Introduce local_lock()
  locking/lockdep: Replace zero-length array with flexible-array
  locking/rtmutex: Remove unused rt_mutex_cmpxchg_relaxed()

2 files changed, 1 insertions, 3 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 6f1c8cba09c6..dd3cc0854c32 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -470,7 +470,7 @@ struct lock_trace {
 	struct hlist_node	hash_entry;
 	u32			hash;
 	u32			nr_entries;
-	unsigned long		entries[0] __aligned(sizeof(unsigned long));
+	unsigned long		entries[] __aligned(sizeof(unsigned long));
 };
 #define LOCK_TRACE_SIZE_IN_LONGS				\
 	(sizeof(struct lock_trace) / sizeof(unsigned long))
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index c9f090d64f00..cfdd5b93264d 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -141,7 +141,6 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
  * set up.
  */
 #ifndef CONFIG_DEBUG_RT_MUTEXES
-# define rt_mutex_cmpxchg_relaxed(l,c,n) (cmpxchg_relaxed(&l->owner, c, n) == c)
 # define rt_mutex_cmpxchg_acquire(l,c,n) (cmpxchg_acquire(&l->owner, c, n) == c)
 # define rt_mutex_cmpxchg_release(l,c,n) (cmpxchg_release(&l->owner, c, n) == c)
 
@@ -202,7 +201,6 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
 }
 
 #else
-# define rt_mutex_cmpxchg_relaxed(l,c,n)	(0)
 # define rt_mutex_cmpxchg_acquire(l,c,n)	(0)
 # define rt_mutex_cmpxchg_release(l,c,n)	(0)