3 files changed, 44 insertions, 10 deletions

diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c
index a0d780ab68c3..82a6e7f6d37f 100644
--- a/drivers/dma-buf/sync_debug.c
+++ b/drivers/dma-buf/sync_debug.c
@@ -132,9 +132,11 @@ static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
 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->name,
+        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)) {
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index dc89b1d484e8..545e2c5c4815 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -80,11 +80,6 @@ struct sync_file *sync_file_create(struct dma_fence *fence)
 
         sync_file->fence = dma_fence_get(fence);
 
-        snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%llu-%d",
-                 fence->ops->get_driver_name(fence),
-                 fence->ops->get_timeline_name(fence), fence->context,
-                 fence->seqno);
-
         return sync_file;
 }
 EXPORT_SYMBOL(sync_file_create);
@@ -129,6 +124,36 @@ struct dma_fence *sync_file_get_fence(int fd)
 }
 EXPORT_SYMBOL(sync_file_get_fence);
 
+/**
+ * sync_file_get_name - get the name of the sync_file
+ * @sync_file:          sync_file to get the fence from
+ * @buf:                destination buffer to copy sync_file name into
+ * @len:                available size of destination buffer.
+ *
+ * Each sync_file may have a name assigned either by the user (when merging
+ * sync_files together) or created from the fence it contains. In the latter
+ * case construction of the name is deferred until use, and so requires
+ * sync_file_get_name().
+ *
+ * Returns: a string representing the name.
+ */
+char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len)
+{
+        if (sync_file->user_name[0]) {
+                strlcpy(buf, sync_file->user_name, len);
+        } else {
+                struct dma_fence *fence = sync_file->fence;
+
+                snprintf(buf, len, "%s-%s%llu-%d",
+                         fence->ops->get_driver_name(fence),
+                         fence->ops->get_timeline_name(fence),
+                         fence->context,
+                         fence->seqno);
+        }
+
+        return buf;
+}
+
 static int sync_file_set_fence(struct sync_file *sync_file,
                                struct dma_fence **fences, int num_fences)
 {
@@ -266,7 +291,7 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
                 goto err;
         }
 
-        strlcpy(sync_file->name, name, sizeof(sync_file->name));
+        strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name));
         return sync_file;
 
 err:
@@ -413,7 +438,7 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
         }
 
 no_fences:
-        strlcpy(info.name, sync_file->name, sizeof(info.name));
+        sync_file_get_name(sync_file, info.name, sizeof(info.name));
         info.status = dma_fence_is_signaled(sync_file->fence);
         info.num_fences = num_fences;
 
diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h
index d37beefdfbd5..5726107963b2 100644
--- a/include/linux/sync_file.h
+++ b/include/linux/sync_file.h
@@ -23,7 +23,6 @@
 /**
  * struct sync_file - sync file to export to the userspace
  * @file:               file representing this fence
- * @name:               name of sync_file.  Useful for debugging
  * @sync_file_list:     membership in global file list
  * @wq:                 wait queue for fence signaling
  * @fence:              fence with the fences in the sync_file
@@ -31,7 +30,14 @@
  */
 struct sync_file {
         struct file             *file;
-        char                    name[32];
+        /**
+         * @user_name:
+         *
+         * Name of the sync file provided by userspace, for merged fences.
+         * Otherwise generated through driver callbacks (in which case the
+         * entire array is 0).
+         */
+        char                    user_name[32];
 #ifdef CONFIG_DEBUG_FS
         struct list_head        sync_file_list;
 #endif
@@ -46,5 +52,6 @@ struct sync_file {
 
 struct sync_file *sync_file_create(struct dma_fence *fence);
 struct dma_fence *sync_file_get_fence(int fd);
+char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len);
 
 #endif /* _LINUX_SYNC_H */