binder: use guards for plain mutex- and spinlock-protected sections

Use 'guard(mutex)' and 'guard(spinlock)' for plain (i.e. non-scoped)
mutex- and spinlock-protected sections, respectively, thus making
locking a bit simpler. Briefly tested with 'stress-ng --binderfs'.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20250626073054.7706-2-dmantipov@yandex.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 10 deletions

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index fcfaf1b899c8..a0a7cb58fc05 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -167,12 +167,8 @@ static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 						   unsigned long user_ptr)
 {
-	struct binder_buffer *buffer;
-
-	mutex_lock(&alloc->mutex);
-	buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
-	mutex_unlock(&alloc->mutex);
-	return buffer;
+	guard(mutex)(&alloc->mutex);
+	return binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 }
 
 static inline void
@@ -1043,7 +1039,7 @@ void binder_alloc_print_allocated(struct seq_file *m,
 	struct binder_buffer *buffer;
 	struct rb_node *n;
 
-	mutex_lock(&alloc->mutex);
+	guard(mutex)(&alloc->mutex);
 	for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
 		buffer = rb_entry(n, struct binder_buffer, rb_node);
 		seq_printf(m, "  buffer %d: %lx size %zd:%zd:%zd %s\n",
@@ -1053,7 +1049,6 @@ void binder_alloc_print_allocated(struct seq_file *m,
 			   buffer->extra_buffers_size,
 			   buffer->transaction ? "active" : "delivered");
 	}
-	mutex_unlock(&alloc->mutex);
 }
 
 /**
@@ -1102,10 +1097,9 @@ int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 	struct rb_node *n;
 	int count = 0;
 
-	mutex_lock(&alloc->mutex);
+	guard(mutex)(&alloc->mutex);
 	for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 		count++;
-	mutex_unlock(&alloc->mutex);
 	return count;
 }