[PATCH 1/5] locking/lockdep: Remove add_chain_cache_classes()

From: Waiman Long
Date: Fri Sep 28 2018 - 13:53:44 EST


The inline function add_chain_cache_classes() is defined, but has no
caller. Just remove it.

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
kernel/locking/lockdep.c | 70 ------------------------------------------------
1 file changed, 70 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index dd13f86..8f9de7c 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2148,76 +2148,6 @@ static int check_no_collision(struct task_struct *curr,
}

/*
- * This is for building a chain between just two different classes,
- * instead of adding a new hlock upon current, which is done by
- * add_chain_cache().
- *
- * This can be called in any context with two classes, while
- * add_chain_cache() must be done within the lock owener's context
- * since it uses hlock which might be racy in another context.
- */
-static inline int add_chain_cache_classes(unsigned int prev,
- unsigned int next,
- unsigned int irq_context,
- u64 chain_key)
-{
- struct hlist_head *hash_head = chainhashentry(chain_key);
- struct lock_chain *chain;
-
- /*
- * Allocate a new chain entry from the static array, and add
- * it to the hash:
- */
-
- /*
- * We might need to take the graph lock, ensure we've got IRQs
- * disabled to make this an IRQ-safe lock.. for recursion reasons
- * lockdep won't complain about its own locking errors.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
- dump_stack();
- return 0;
- }
-
- chain = lock_chains + nr_lock_chains++;
- chain->chain_key = chain_key;
- chain->irq_context = irq_context;
- chain->depth = 2;
- if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
- chain->base = nr_chain_hlocks;
- nr_chain_hlocks += chain->depth;
- chain_hlocks[chain->base] = prev - 1;
- chain_hlocks[chain->base + 1] = next -1;
- }
-#ifdef CONFIG_DEBUG_LOCKDEP
- /*
- * Important for check_no_collision().
- */
- else {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
- dump_stack();
- return 0;
- }
-#endif
-
- hlist_add_head_rcu(&chain->entry, hash_head);
- debug_atomic_inc(chain_lookup_misses);
- inc_chains();
-
- return 1;
-}
-
-/*
* Adds a dependency chain into chain hashtable. And must be called with
* graph_lock held.
*
--
1.8.3.1