Merge tag 'dma-mapping-6.6-2023-09-09' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:

 - move a dma-debug call that prints a message out from a lock that's
   causing problems with the lock order in serial drivers (Sergey
   Senozhatsky)

 - fix the CONFIG_DMA_NUMA_CMA Kconfig entry to have the right
   dependency and not default to y (Christoph Hellwig)

 - move an ifdef a bit to remove a __maybe_unused that seems to trip up
   some sensitivities (Christoph Hellwig)

 - revert a bogus check in the CMA allocator (Zhenhua Huang)

* tag 'dma-mapping-6.6-2023-09-09' of git://git.infradead.org/users/hch/dma-mapping:
  Revert "dma-contiguous: check for memory region overlap"
  dma-pool: remove a __maybe_unused label in atomic_pool_expand
  dma-contiguous: fix the Kconfig entry for CONFIG_DMA_NUMA_CMA
  dma-debug: don't call __dma_entry_alloc_check_leak() under free_entries_lock

1 files changed, 15 insertions, 5 deletions

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index f190651bcadd..06366acd27b0 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -637,15 +637,19 @@ static struct dma_debug_entry *__dma_entry_alloc(void)
 	return entry;
 }
 
-static void __dma_entry_alloc_check_leak(void)
+/*
+ * This should be called outside of free_entries_lock scope to avoid potential
+ * deadlocks with serial consoles that use DMA.
+ */
+static void __dma_entry_alloc_check_leak(u32 nr_entries)
 {
-	u32 tmp = nr_total_entries % nr_prealloc_entries;
+	u32 tmp = nr_entries % nr_prealloc_entries;
 
 	/* Shout each time we tick over some multiple of the initial pool */
 	if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
 		pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
-			nr_total_entries,
-			(nr_total_entries / nr_prealloc_entries));
+			nr_entries,
+			(nr_entries / nr_prealloc_entries));
 	}
 }
 
@@ -656,8 +660,10 @@ static void __dma_entry_alloc_check_leak(void)
  */
 static struct dma_debug_entry *dma_entry_alloc(void)
 {
+	bool alloc_check_leak = false;
 	struct dma_debug_entry *entry;
 	unsigned long flags;
+	u32 nr_entries;
 
 	spin_lock_irqsave(&free_entries_lock, flags);
 	if (num_free_entries == 0) {
@@ -667,13 +673,17 @@ static struct dma_debug_entry *dma_entry_alloc(void)
 			pr_err("debugging out of memory - disabling\n");
 			return NULL;
 		}
-		__dma_entry_alloc_check_leak();
+		alloc_check_leak = true;
+		nr_entries = nr_total_entries;
 	}
 
 	entry = __dma_entry_alloc();
 
 	spin_unlock_irqrestore(&free_entries_lock, flags);
 
+	if (alloc_check_leak)
+		__dma_entry_alloc_check_leak(nr_entries);
+
 #ifdef CONFIG_STACKTRACE
 	entry->stack_len = stack_trace_save(entry->stack_entries,
 					    ARRAY_SIZE(entry->stack_entries),