Merge tag 'asoc-v6.13' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-next

ASoC: Updates for v6.13

This release was mainly about new drivers, there's a very large batch of
new drivers and devices including quite a few from newer vendors which
is great to see.  Other than the new drivers and the usual routine fixes
and enhancements the bulk of the work has been Morimoto-san's continuing
work on simplifiying APIs, plus a few other bits:

 - More API simplifications from Morimoto-san.
 - Renaming of the sh directory to Renesas to reflect the focus on other
   architectures.
 - Factoring out of some of the common code for Realtek devices.
 - Support for Allwinner H616, AMD ACP 6.3 systems, AWInic AW88081,
   Cirrus Logic CS32L84, Everest ES8328, Iron Devices SMA1307, Longsoon
   I2S, NeoFidelity NTP8918 and NTP8835, Philips UDA1342, Qualcomm
   SM8750, RealTek RT721, and ST Microelectronics STM32MP25.

1 files changed, 43 insertions, 13 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2fb328880b50..03fd4bc39ea1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3588,10 +3588,27 @@ int split_folio_to_list(struct folio *folio, struct list_head *list)
 	return split_huge_page_to_list_to_order(&folio->page, list, ret);
 }
 
-void __folio_undo_large_rmappable(struct folio *folio)
+/*
+ * __folio_unqueue_deferred_split() is not to be called directly:
+ * the folio_unqueue_deferred_split() inline wrapper in mm/internal.h
+ * limits its calls to those folios which may have a _deferred_list for
+ * queueing THP splits, and that list is (racily observed to be) non-empty.
+ *
+ * It is unsafe to call folio_unqueue_deferred_split() until folio refcount is
+ * zero: because even when split_queue_lock is held, a non-empty _deferred_list
+ * might be in use on deferred_split_scan()'s unlocked on-stack list.
+ *
+ * If memory cgroups are enabled, split_queue_lock is in the mem_cgroup: it is
+ * therefore important to unqueue deferred split before changing folio memcg.
+ */
+bool __folio_unqueue_deferred_split(struct folio *folio)
 {
 	struct deferred_split *ds_queue;
 	unsigned long flags;
+	bool unqueued = false;
+
+	WARN_ON_ONCE(folio_ref_count(folio));
+	WARN_ON_ONCE(!mem_cgroup_disabled() && !folio_memcg(folio));
 
 	ds_queue = get_deferred_split_queue(folio);
 	spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
@@ -3603,8 +3620,11 @@ void __folio_undo_large_rmappable(struct folio *folio)
 				      MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, -1);
 		}
 		list_del_init(&folio->_deferred_list);
+		unqueued = true;
 	}
 	spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
+
+	return unqueued;	/* useful for debug warnings */
 }
 
 /* partially_mapped=false won't clear PG_partially_mapped folio flag */
@@ -3627,14 +3647,11 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped)
 		return;
 
 	/*
-	 * The try_to_unmap() in page reclaim path might reach here too,
-	 * this may cause a race condition to corrupt deferred split queue.
-	 * And, if page reclaim is already handling the same folio, it is
-	 * unnecessary to handle it again in shrinker.
-	 *
-	 * Check the swapcache flag to determine if the folio is being
-	 * handled by page reclaim since THP swap would add the folio into
-	 * swap cache before calling try_to_unmap().
+	 * Exclude swapcache: originally to avoid a corrupt deferred split
+	 * queue. Nowadays that is fully prevented by mem_cgroup_swapout();
+	 * but if page reclaim is already handling the same folio, it is
+	 * unnecessary to handle it again in the shrinker, so excluding
+	 * swapcache here may still be a useful optimization.
 	 */
 	if (folio_test_swapcache(folio))
 		return;
@@ -3718,8 +3735,8 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
 	struct deferred_split *ds_queue = &pgdata->deferred_split_queue;
 	unsigned long flags;
 	LIST_HEAD(list);
-	struct folio *folio, *next;
-	int split = 0;
+	struct folio *folio, *next, *prev = NULL;
+	int split = 0, removed = 0;
 
 #ifdef CONFIG_MEMCG
 	if (sc->memcg)
@@ -3775,15 +3792,28 @@ next:
 		 */
 		if (!did_split && !folio_test_partially_mapped(folio)) {
 			list_del_init(&folio->_deferred_list);
-			ds_queue->split_queue_len--;
+			removed++;
+		} else {
+			/*
+			 * That unlocked list_del_init() above would be unsafe,
+			 * unless its folio is separated from any earlier folios
+			 * left on the list (which may be concurrently unqueued)
+			 * by one safe folio with refcount still raised.
+			 */
+			swap(folio, prev);
 		}
-		folio_put(folio);
+		if (folio)
+			folio_put(folio);
 	}
 
 	spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
 	list_splice_tail(&list, &ds_queue->split_queue);
+	ds_queue->split_queue_len -= removed;
 	spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
 
+	if (prev)
+		folio_put(prev);
+
 	/*
 	 * Stop shrinker if we didn't split any page, but the queue is empty.
 	 * This can happen if pages were freed under us.