dma-buf: add dma_fence_describe and dma_resv_describe v2

Add functions to dump dma_fence and dma_resv objects into a seq_file and
use them for printing the debugfs information.

v2: fix missing include reported by test robot.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211103081231.18578-2-christian.koenig@amd.com

drivers/dma-buf/dma-buf.c

@@ -1321,8 +1321,6 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
 {
 	struct dma_buf *buf_obj;
 	struct dma_buf_attachment *attach_obj;
-	struct dma_resv_iter cursor;
-	struct dma_fence *fence;
 	int count = 0, attach_count;
 	size_t size = 0;
 	int ret;
@@ -1350,14 +1348,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
 				file_inode(buf_obj->file)->i_ino,
 				buf_obj->name ?: "");
 
-		dma_resv_for_each_fence(&cursor, buf_obj->resv, true, fence) {
+		dma_resv_describe(buf_obj->resv, s);
-			seq_printf(s, "\t%s fence: %s %s %ssignalled\n",
-				   dma_resv_iter_is_exclusive(&cursor) ?
-					"Exclusive" : "Shared",
-				   fence->ops->get_driver_name(fence),
-				   fence->ops->get_timeline_name(fence),
-				   dma_fence_is_signaled(fence) ? "" : "un");
-		}
 
 		seq_puts(s, "\tAttached Devices:\n");
 		attach_count = 0;

drivers/dma-buf/dma-fence.c

@@ -15,6 +15,7 @@
 #include <linux/atomic.h>
 #include <linux/dma-fence.h>
 #include <linux/sched/signal.h>
+#include <linux/seq_file.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/dma_fence.h>
@@ -907,6 +908,22 @@ err_free_cb:
 }
 EXPORT_SYMBOL(dma_fence_wait_any_timeout);
 
+/**
+ * dma_fence_describe - Dump fence describtion into seq_file
+ * @fence: the 6fence to describe
+ * @seq: the seq_file to put the textual description into
+ *
+ * Dump a textual description of the fence and it's state into the seq_file.
+ */
+void dma_fence_describe(struct dma_fence *fence, struct seq_file *seq)
+{
+	seq_printf(seq, "%s %s seq %llu %ssignalled\n",
+		   fence->ops->get_driver_name(fence),
+		   fence->ops->get_timeline_name(fence), fence->seqno,
+		   dma_fence_is_signaled(fence) ? "" : "un");
+}
+EXPORT_SYMBOL(dma_fence_describe);
+
 /**
  * dma_fence_init - Initialize a custom fence.
  * @fence: the fence to initialize

drivers/dma-buf/dma-resv.c

@@ -38,6 +38,7 @@
 #include <linux/mm.h>
 #include <linux/sched/mm.h>
 #include <linux/mmu_notifier.h>
+#include <linux/seq_file.h>
 
 /**
  * DOC: Reservation Object Overview
@@ -666,6 +667,28 @@ bool dma_resv_test_signaled(struct dma_resv *obj, bool test_all)
 }
 EXPORT_SYMBOL_GPL(dma_resv_test_signaled);
 
+/**
+ * dma_resv_describe - Dump description of the resv object into seq_file
+ * @obj: the reservation object
+ * @seq: the seq_file to dump the description into
+ *
+ * Dump a textual description of the fences inside an dma_resv object into the
+ * seq_file.
+ */
+void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq)
+{
+	struct dma_resv_iter cursor;
+	struct dma_fence *fence;
+
+	dma_resv_for_each_fence(&cursor, obj, true, fence) {
+		seq_printf(seq, "\t%s fence:",
+			   dma_resv_iter_is_exclusive(&cursor) ?
+				"Exclusive" : "Shared");
+		dma_fence_describe(fence, seq);
+	}
+}
+EXPORT_SYMBOL_GPL(dma_resv_describe);
+
 #if IS_ENABLED(CONFIG_LOCKDEP)
 static int __init dma_resv_lockdep(void)
 {

include/linux/dma-fence.h

@@ -264,6 +264,7 @@ void dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
 
 void dma_fence_release(struct kref *kref);
 void dma_fence_free(struct dma_fence *fence);
+void dma_fence_describe(struct dma_fence *fence, struct seq_file *seq);
 
 /**
  * dma_fence_put - decreases refcount of the fence

include/linux/dma-resv.h

@@ -490,5 +490,6 @@ int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
 long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr,
 			   unsigned long timeout);
 bool dma_resv_test_signaled(struct dma_resv *obj, bool test_all);
+void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq);
 
 #endif /* _LINUX_RESERVATION_H */