[PATCH] mm/mmu_notifiers: Use hlist_for_each_entry_srcu() for SRCU list traversal

[PATCH] mm/mmu_notifiers: Use hlist_for_each_entry_srcu() for SRCU list traversal

[lirongqing]

From: Li RongQing <lirongqing@baidu.com>

The mmu_notifier_subscriptions list is protected by SRCU. While the
current code uses hlist_for_each_entry_rcu() with an explicit SRCU
lockdep check, it is more appropriate to use the dedicated
hlist_for_each_entry_srcu() macro.

This change aligns the code with the preferred kernel API for SRCU-protected
lists, improving code clarity and ensuring that the synchronization
method is explicitly documented by the iterator name itself.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 mm/mmu_notifier.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 8e0125d..2a2a582 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -309,7 +309,7 @@ static void mn_hlist_release(struct mmu_notifier_subscriptions *subscriptions,
 	 * ->release returns.
 	 */
 	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(subscription, &subscriptions->list, hlist,
+	hlist_for_each_entry_srcu(subscription, &subscriptions->list, hlist,
 				 srcu_read_lock_held(&srcu))
 		/*
 		 * If ->release runs before mmu_notifier_unregister it must be
@@ -372,7 +372,7 @@ int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
 	int young = 0, id;
 
 	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(subscription,
+	hlist_for_each_entry_srcu(subscription,
 				 &mm->notifier_subscriptions->list, hlist,
 				 srcu_read_lock_held(&srcu)) {
 		if (subscription->ops->clear_flush_young)
@@ -392,7 +392,7 @@ int __mmu_notifier_clear_young(struct mm_struct *mm,
 	int young = 0, id;
 
 	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(subscription,
+	hlist_for_each_entry_srcu(subscription,
 				 &mm->notifier_subscriptions->list, hlist,
 				 srcu_read_lock_held(&srcu)) {
 		if (subscription->ops->clear_young)
@@ -411,7 +411,7 @@ int __mmu_notifier_test_young(struct mm_struct *mm,
 	int young = 0, id;
 
 	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(subscription,
+	hlist_for_each_entry_srcu(subscription,
 				 &mm->notifier_subscriptions->list, hlist,
 				 srcu_read_lock_held(&srcu)) {
 		if (subscription->ops->test_young) {
@@ -466,7 +466,7 @@ static int mn_hlist_invalidate_range_start(
 	int id;
 
 	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(subscription, &subscriptions->list, hlist,
+	hlist_for_each_entry_srcu(subscription, &subscriptions->list, hlist,
 				 srcu_read_lock_held(&srcu)) {
 		const struct mmu_notifier_ops *ops = subscription->ops;
 
@@ -504,7 +504,7 @@ static int mn_hlist_invalidate_range_start(
 		 * notifiers and one or more failed start, any that succeeded
 		 * start are expecting their end to be called.  Do so now.
 		 */
-		hlist_for_each_entry_rcu(subscription, &subscriptions->list,
+		hlist_for_each_entry_srcu(subscription, &subscriptions->list,
 					 hlist, srcu_read_lock_held(&srcu)) {
 			if (!subscription->ops->invalidate_range_end)
 				continue;
@@ -542,7 +542,7 @@ mn_hlist_invalidate_end(struct mmu_notifier_subscriptions *subscriptions,
 	int id;
 
 	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(subscription, &subscriptions->list, hlist,
+	hlist_for_each_entry_srcu(subscription, &subscriptions->list, hlist,
 				 srcu_read_lock_held(&srcu)) {
 		if (subscription->ops->invalidate_range_end) {
 			if (!mmu_notifier_range_blockable(range))
@@ -577,7 +577,7 @@ void __mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm,
 	int id;
 
 	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(subscription,
+	hlist_for_each_entry_srcu(subscription,
 				 &mm->notifier_subscriptions->list, hlist,
 				 srcu_read_lock_held(&srcu)) {
 		if (subscription->ops->arch_invalidate_secondary_tlbs)
@@ -714,7 +714,7 @@ find_get_mmu_notifier(struct mm_struct *mm, const struct mmu_notifier_ops *ops)
 	struct mmu_notifier *subscription;
 
 	spin_lock(&mm->notifier_subscriptions->lock);
-	hlist_for_each_entry_rcu(subscription,
+	hlist_for_each_entry_srcu(subscription,
 				 &mm->notifier_subscriptions->list, hlist,
 				 lockdep_is_held(&mm->notifier_subscriptions->lock)) {
 		if (subscription->ops != ops)
-- 
2.9.4

Re: [PATCH] mm/mmu_notifiers: Use hlist_for_each_entry_srcu() for SRCU list traversal

[SeongJae Park]

On Wed, 4 Feb 2026 03:09:37 -0500 lirongqing <lirongqing@baidu.com> wrote:

> From: Li RongQing <lirongqing@baidu.com>
> 
> The mmu_notifier_subscriptions list is protected by SRCU. While the
> current code uses hlist_for_each_entry_rcu() with an explicit SRCU
> lockdep check, it is more appropriate to use the dedicated
> hlist_for_each_entry_srcu() macro.
> 
> This change aligns the code with the preferred kernel API for SRCU-protected
> lists, improving code clarity and ensuring that the synchronization
> method is explicitly documented by the iterator name itself.
> 
> Signed-off-by: Li RongQing <lirongqing@baidu.com>

Acked-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

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