[PATCH v4 04/30] locking/lockdep: Pass lock chain from validate_chain() to check_prev_add()

[Yuyang Du]

The pointer of lock chains is passed all the way from validate_chain()
to check_prev_add(). This is aimed for the later effort to associate lock
chains to lock dependencies.

No functional change.

Signed-off-by: Yuyang Du <duyuyang@xxxxxxxxx>
---
 kernel/locking/lockdep.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 51918d2..a0e62e5 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2441,7 +2441,7 @@ static inline void inc_chains(void)
 static int
 check_prev_add(struct task_struct *curr, struct held_lock *prev,
 	       struct held_lock *next, int distance,
-	       struct lock_trace **const trace)
+	       struct lock_trace **const trace, struct lock_chain *chain)
 {
 	struct lock_list *entry;
 	int ret;
@@ -2549,7 +2549,8 @@ static inline void inc_chains(void)
  * the end of this context's lock-chain - whichever comes first.
  */
 static int
-check_prevs_add(struct task_struct *curr, struct held_lock *next)
+check_prevs_add(struct task_struct *curr, struct held_lock *next,
+		struct lock_chain *chain)
 {
 	struct lock_trace *trace = NULL;
 	int depth = curr->lockdep_depth;
@@ -2580,7 +2581,7 @@ static inline void inc_chains(void)
 		 */
 		if (hlock->read != 2 && hlock->check) {
 			int ret = check_prev_add(curr, hlock, next, distance,
-						 &trace);
+						 &trace, chain);
 			if (!ret)
 				return 0;
 
@@ -2920,6 +2921,7 @@ static int validate_chain(struct task_struct *curr,
 			  struct held_lock *hlock,
 			  int chain_head, u64 chain_key)
 {
+	struct lock_chain *chain;
 	/*
 	 * Trylock needs to maintain the stack of held locks, but it
 	 * does not add new dependencies, because trylock can be done
@@ -2931,7 +2933,7 @@ static int validate_chain(struct task_struct *curr,
 	 * graph_lock for us)
 	 */
 	if (!hlock->trylock && hlock->check &&
-	    lookup_chain_cache_add(curr, hlock, chain_key)) {
+	    (chain = lookup_chain_cache_add(curr, hlock, chain_key))) {
 		/*
 		 * Check whether last held lock:
 		 *
@@ -2966,7 +2968,7 @@ static int validate_chain(struct task_struct *curr,
 		 * of the chain, and if it's not a secondary read-lock:
 		 */
 		if (!chain_head && ret != 2) {
-			if (!check_prevs_add(curr, hlock))
+			if (!check_prevs_add(curr, hlock, chain))
 				return 0;
 		}
 
-- 
1.8.3.1