[PATCH v3 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 a later effort to associate lock
chains to lock dependencies.

No functional change.

Signed-off-by: Yuyang Du <duyuyang@xxxxxxxxx>
---
 kernel/locking/lockdep.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index d545b6c..f171c6e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2370,7 +2370,8 @@ 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 *trace)
+	       struct held_lock *next, int distance, struct lock_trace *trace,
+	       struct lock_chain *chain)
 {
 	struct lock_list *entry;
 	int ret;
@@ -2475,7 +2476,8 @@ 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 = { .nr_entries = 0 };
 	int depth = curr->lockdep_depth;
@@ -2506,7 +2508,7 @@ 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;
 
@@ -2846,6 +2848,7 @@ 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
@@ -2857,7 +2860,7 @@ 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:
 		 *
@@ -2892,7 +2895,7 @@ 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