dma-buf/sw-sync: Remove unused debug code

sync_file_debug_add() and sync_file_debug_remove() have been unused
since 2016's
commit d4cab38e15 ("staging/android: prepare sync_file for de-staging")

Remove them.

Since sync_file_debug_add was the only thing to add to
sync_file_list_head, the code that dumps it in part of
sync_info_debugfs_show can be removed, and the declaration of
the list and it's associated lock can be removed.
(The 'fences:\n...' marker in that debugfs file is left in
so as not to change the output)

That leaves the sync_print_sync_file() helper unused, and
is thus removed.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20250505233838.105668-1-linux@treblig.org

drivers/dma-buf/sync_debug.c

@@ -12,8 +12,6 @@ static struct dentry *dbgfs;
 
 static LIST_HEAD(sync_timeline_list_head);
 static DEFINE_SPINLOCK(sync_timeline_list_lock);
-static LIST_HEAD(sync_file_list_head);
-static DEFINE_SPINLOCK(sync_file_list_lock);
 
 void sync_timeline_debug_add(struct sync_timeline *obj)
 {
@@ -33,24 +31,6 @@ void sync_timeline_debug_remove(struct sync_timeline *obj)
 	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
 }
 
-void sync_file_debug_add(struct sync_file *sync_file)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&sync_file_list_lock, flags);
-	list_add_tail(&sync_file->sync_file_list, &sync_file_list_head);
-	spin_unlock_irqrestore(&sync_file_list_lock, flags);
-}
-
-void sync_file_debug_remove(struct sync_file *sync_file)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&sync_file_list_lock, flags);
-	list_del(&sync_file->sync_file_list);
-	spin_unlock_irqrestore(&sync_file_list_lock, flags);
-}
-
 static const char *sync_status_str(int status)
 {
 	if (status < 0)
@@ -101,26 +81,6 @@ static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
 	spin_unlock(&obj->lock);
 }
 
-static void sync_print_sync_file(struct seq_file *s,
-				  struct sync_file *sync_file)
-{
-	char buf[128];
-	int i;
-
-	seq_printf(s, "[%p] %s: %s\n", sync_file,
-		   sync_file_get_name(sync_file, buf, sizeof(buf)),
-		   sync_status_str(dma_fence_get_status(sync_file->fence)));
-
-	if (dma_fence_is_array(sync_file->fence)) {
-		struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
-
-		for (i = 0; i < array->num_fences; ++i)
-			sync_print_fence(s, array->fences[i], true);
-	} else {
-		sync_print_fence(s, sync_file->fence, true);
-	}
-}
-
 static int sync_info_debugfs_show(struct seq_file *s, void *unused)
 {
 	struct list_head *pos;
@@ -140,15 +100,6 @@ static int sync_info_debugfs_show(struct seq_file *s, void *unused)
 
 	seq_puts(s, "fences:\n--------------\n");
 
-	spin_lock_irq(&sync_file_list_lock);
-	list_for_each(pos, &sync_file_list_head) {
-		struct sync_file *sync_file =
-			container_of(pos, struct sync_file, sync_file_list);
-
-		sync_print_sync_file(s, sync_file);
-		seq_putc(s, '\n');
-	}
-	spin_unlock_irq(&sync_file_list_lock);
 	return 0;
 }
 

drivers/dma-buf/sync_debug.h

@@ -68,7 +68,5 @@ extern const struct file_operations sw_sync_debugfs_fops;
 
 void sync_timeline_debug_add(struct sync_timeline *obj);
 void sync_timeline_debug_remove(struct sync_timeline *obj);
-void sync_file_debug_add(struct sync_file *fence);
-void sync_file_debug_remove(struct sync_file *fence);
 
 #endif /* _LINUX_SYNC_H */