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From: Yuyang Du <duyuyang@gmail.com>
To: peterz@infradead.org, will.deacon@arm.com, mingo@kernel.org
Cc: bvanassche@acm.org, ming.lei@redhat.com, frederic@kernel.org,
	tglx@linutronix.de, linux-kernel@vger.kernel.org,
	longman@redhat.com, paulmck@linux.vnet.ibm.com,
	boqun.feng@gmail.com, Yuyang Du <duyuyang@gmail.com>
Subject: [PATCH v3 09/30] locking/lockdep: Remove chain_head argument in validate_chain()
Date: Fri, 28 Jun 2019 17:15:07 +0800	[thread overview]
Message-ID: <20190628091528.17059-10-duyuyang@gmail.com> (raw)
In-Reply-To: <20190628091528.17059-1-duyuyang@gmail.com>

This argument says whether the chain is a head, meaning having just one
lock, which can actually be tested by lock_chain->depth. So there is no
need to explicitly make this argument, so remove it.

No functional change.

Signed-off-by: Yuyang Du <duyuyang@gmail.com>
---
 kernel/locking/lockdep.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4ffb4df..e2ad673 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2807,9 +2807,8 @@ static inline struct lock_chain *lookup_chain_cache(u64 chain_key)
 	return add_chain_cache(curr, hlock, chain_key);
 }
 
-static int validate_chain(struct task_struct *curr,
-			  struct held_lock *hlock,
-			  int chain_head, u64 chain_key)
+static int validate_chain(struct task_struct *curr, struct held_lock *hlock,
+			  u64 chain_key)
 {
 	struct lock_chain *chain;
 	/*
@@ -2857,7 +2856,7 @@ static int validate_chain(struct task_struct *curr,
 		 * Add dependency only if this lock is not the head
 		 * of the chain, and if it's not a secondary read-lock:
 		 */
-		if (!chain_head && ret != 2) {
+		if (chain->depth > 1 && ret != 2) {
 			if (!check_prevs_add(curr, hlock, chain))
 				return 0;
 		}
@@ -2874,7 +2873,7 @@ static int validate_chain(struct task_struct *curr,
 #else
 static inline int validate_chain(struct task_struct *curr,
 				 struct held_lock *hlock,
-				 int chain_head, u64 chain_key)
+				 u64 chain_key)
 {
 	return 1;
 }
@@ -3707,7 +3706,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 	struct lock_class *class = NULL;
 	struct held_lock *hlock;
 	unsigned int depth;
-	int chain_head = 0;
 	int class_idx;
 	u64 chain_key;
 
@@ -3821,14 +3819,12 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 		 */
 		if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY))
 			return 0;
-		chain_head = 1;
 	}
 
 	hlock->prev_chain_key = chain_key;
-	if (separate_irq_context(curr, hlock)) {
+	if (separate_irq_context(curr, hlock))
 		chain_key = INITIAL_CHAIN_KEY;
-		chain_head = 1;
-	}
+
 	chain_key = iterate_chain_key(chain_key, class_idx);
 
 	if (nest_lock && !__lock_is_held(nest_lock, -1)) {
@@ -3841,7 +3837,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 		WARN_ON_ONCE(!hlock_class(hlock)->key);
 	}
 
-	if (!validate_chain(curr, hlock, chain_head, chain_key))
+	if (!validate_chain(curr, hlock, chain_key))
 		return 0;
 
 	curr->curr_chain_key = chain_key;
-- 
1.8.3.1


  parent reply	other threads:[~2019-06-28  9:16 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-28  9:14 [PATCH v3 00/30] Support recursive-read lock deadlock detection Yuyang Du
2019-06-28  9:14 ` [PATCH v3 01/30] locking/lockdep: Rename deadlock check functions Yuyang Du
2019-06-28  9:15 ` [PATCH v3 02/30] locking/lockdep: Change return type of add_chain_cache() Yuyang Du
2019-06-28  9:15 ` [PATCH v3 03/30] locking/lockdep: Change return type of lookup_chain_cache_add() Yuyang Du
2019-06-28  9:15 ` [PATCH v3 04/30] locking/lockdep: Pass lock chain from validate_chain() to check_prev_add() Yuyang Du
2019-06-28  9:15 ` [PATCH v3 05/30] locking/lockdep: Add lock chain list_head field in struct lock_list and lock_chain Yuyang Du
2019-06-28  9:15 ` [PATCH v3 06/30] locking/lockdep: Update comments in struct lock_list and held_lock Yuyang Du
2019-06-28  9:15 ` [PATCH v3 07/30] locking/lockdep: Remove indirect dependency redundancy check Yuyang Du
2019-06-28  9:15 ` [PATCH v3 08/30] locking/lockdep: Skip checks if direct dependency is already present Yuyang Du
2019-06-28  9:15 ` Yuyang Du [this message]
2019-06-28  9:15 ` [PATCH v3 10/30] locking/lockdep: Remove useless lock type assignment Yuyang Du
2019-06-28  9:15 ` [PATCH v3 11/30] locking/lockdep: Specify the depth of current lock stack in lookup_chain_cache_add() Yuyang Du
2019-06-28  9:15 ` [PATCH v3 12/30] locking/lockdep: Treat every lock dependency as in a new lock chain Yuyang Du
2019-06-28  9:15 ` [PATCH v3 13/30] locking/lockdep: Combine lock_lists in struct lock_class into an array Yuyang Du
2019-06-28  9:15 ` [PATCH v3 14/30] locking/lockdep: Consolidate forward and backward lock_lists into one Yuyang Du
2019-06-28  9:15 ` [PATCH v3 15/30] locking/lockdep: Add lock chains to direct lock dependency graph Yuyang Du
2019-06-28  9:15 ` [PATCH v3 16/30] locking/lockdep: Use lock type enum to explicitly specify read or write locks Yuyang Du
2019-06-28  9:15 ` [PATCH v3 17/30] locking/lockdep: Add read-write type for a lock dependency Yuyang Du
2019-07-10  5:18   ` Boqun Feng
2019-07-11  5:02     ` Yuyang Du
2019-06-28  9:15 ` [PATCH v3 18/30] locking/lockdep: Add helper functions to operate on the searched path Yuyang Du
2019-06-28  9:15 ` [PATCH v3 19/30] locking/lockdep: Update direct dependency's read-write type if it exists Yuyang Du
2019-06-28  9:15 ` [PATCH v3 20/30] locking/lockdep: Introduce chain_hlocks_type for held lock's read-write type Yuyang Du
2019-06-28  9:15 ` [PATCH v3 21/30] locking/lockdep: Hash held lock's read-write type into chain key Yuyang Du
2019-06-28  9:15 ` [PATCH v3 22/30] locking/lockdep: Adjust BFS algorithm to support multiple matches Yuyang Du
2019-06-28  9:15 ` [PATCH v3 23/30] locking/lockdep: Define the two task model for lockdep checks formally Yuyang Du
2019-06-28  9:15 ` [PATCH v3 24/30] locking/lockdep: Introduce mark_lock_unaccessed() Yuyang Du
2019-06-28  9:15 ` [PATCH v3 25/30] locking/lockdep: Add nest lock type Yuyang Du
2019-06-28  9:15 ` [PATCH v3 26/30] locking/lockdep: Add lock exclusiveness table Yuyang Du
2019-06-28  9:15 ` [PATCH v3 27/30] locking/lockdep: Support read-write lock's deadlock detection Yuyang Du
2019-06-28  9:15 ` [PATCH v3 28/30] locking/lockdep: Adjust selftest case for recursive read lock Yuyang Du
2019-06-28  9:15 ` [PATCH v3 29/30] locking/lockdep: Add more lockdep selftest cases Yuyang Du
2019-06-28  9:15 ` [PATCH v3 30/30] locking/lockdep: Remove irq-safe to irq-unsafe read check Yuyang Du
2019-07-10  5:30   ` Boqun Feng
2019-07-10  6:30     ` Yuyang Du
2019-07-10  1:54 ` [PATCH v3 00/30] Support recursive-read lock deadlock detection Yuyang Du

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