dma-buf: add some tracepoints to debug.

Since we can only inspect dmabuf by iterating over process FDs or the
dmabuf_list, we need to add our own tracepoints to track its status in
real time in production.

For example:
   binder:3016_1-3102    [006] ...1.   255.126521: dma_buf_export: exp_name=qcom,system size=12685312 ino=2738
   binder:3016_1-3102    [006] ...1.   255.126528: dma_buf_fd: exp_name=qcom,system size=12685312 ino=2738 fd=8
   binder:3016_1-3102    [006] ...1.   255.126642: dma_buf_mmap_internal: exp_name=qcom,system size=28672 ino=2739
     kworker/6:1-86      [006] ...1.   255.127194: dma_buf_put: exp_name=qcom,system size=12685312 ino=2738
    RenderThread-9293    [006] ...1.   316.618179: dma_buf_get: exp_name=qcom,system size=12771328 ino=2762 fd=176
    RenderThread-9293    [006] ...1.   316.618195: dma_buf_dynamic_attach: exp_name=qcom,system size=12771328 ino=2762 attachment:ffffff880a18dd00 is_dynamic=0 dev_name=kgsl-3d0
    RenderThread-9293    [006] ...1.   318.878220: dma_buf_detach: exp_name=qcom,system size=12771328 ino=2762 attachment:ffffff880a18dd00 is_dynamic=0 dev_name=kgsl-3d0

Signed-off-by: Xiang Gao <gaoxiang17@xiaomi.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20260109115411.115270-1-gxxa03070307@gmail.com

2 files changed, 29 insertions, 30 deletions

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 8e23580f1754..77555096e4c7 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -46,12 +46,10 @@
  */
 #define DMA_BUF_TRACE(FUNC, ...)					\
 	do {								\
-		if (FUNC##_enabled()) {					\
+		/* Always expose lock if lockdep is enabled */		\
+		if (IS_ENABLED(CONFIG_LOCKDEP) || FUNC##_enabled()) {	\
 			guard(spinlock)(&dmabuf->name_lock);		\
 			FUNC(__VA_ARGS__);				\
-		} else if (IS_ENABLED(CONFIG_LOCKDEP)) {		\
-			/* Expose this lock when lockdep is enabled */	\
-			guard(spinlock)(&dmabuf->name_lock);		\
 		}							\
 	} while (0)
 
@@ -795,8 +793,7 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags)
 		return -EINVAL;
 
 	fd = FD_ADD(flags, dmabuf->file);
-	if (fd >= 0)
-		DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd);
+	DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd);
 
 	return fd;
 }
diff --git a/include/trace/events/dma_buf.h b/include/trace/events/dma_buf.h
index 35f8140095f4..3bb88d05bcc8 100644
--- a/include/trace/events/dma_buf.h
+++ b/include/trace/events/dma_buf.h
@@ -15,15 +15,15 @@ DECLARE_EVENT_CLASS(dma_buf,
 	TP_ARGS(dmabuf),
 
 	TP_STRUCT__entry(
-		__string(exp_name, dmabuf->exp_name)
-		__field(size_t, size)
-		__field(ino_t, ino)
+		__string(	exp_name,		dmabuf->exp_name)
+		__field(	size_t,			size)
+		__field(	ino_t,			ino)
 	),
 
 	TP_fast_assign(
 		__assign_str(exp_name);
-		__entry->size = dmabuf->size;
-		__entry->ino = dmabuf->file->f_inode->i_ino;
+		__entry->size	= dmabuf->size;
+		__entry->ino	= dmabuf->file->f_inode->i_ino;
 	),
 
 	TP_printk("exp_name=%s size=%zu ino=%lu",
@@ -40,21 +40,21 @@ DECLARE_EVENT_CLASS(dma_buf_attach_dev,
 	TP_ARGS(dmabuf, attach, is_dynamic, dev),
 
 	TP_STRUCT__entry(
-		__string(dev_name, dev_name(dev))
-		__string(exp_name, dmabuf->exp_name)
-		__field(size_t, size)
-		__field(ino_t, ino)
-		__field(struct dma_buf_attachment *, attach)
-		__field(bool, is_dynamic)
+		__string(	dev_name,			dev_name(dev))
+		__string(	exp_name,			dmabuf->exp_name)
+		__field(	size_t,				size)
+		__field(	ino_t,				ino)
+		__field(	struct dma_buf_attachment *,	attach)
+		__field(	bool,				is_dynamic)
 	),
 
 	TP_fast_assign(
 		__assign_str(dev_name);
 		__assign_str(exp_name);
-		__entry->size = dmabuf->size;
-		__entry->ino = dmabuf->file->f_inode->i_ino;
-		__entry->is_dynamic = is_dynamic;
-		__entry->attach = attach;
+		__entry->size		= dmabuf->size;
+		__entry->ino		= dmabuf->file->f_inode->i_ino;
+		__entry->is_dynamic	= is_dynamic;
+		__entry->attach		= attach;
 	),
 
 	TP_printk("exp_name=%s size=%zu ino=%lu attachment:%p is_dynamic=%d dev_name=%s",
@@ -73,17 +73,17 @@ DECLARE_EVENT_CLASS(dma_buf_fd,
 	TP_ARGS(dmabuf, fd),
 
 	TP_STRUCT__entry(
-		__string(exp_name, dmabuf->exp_name)
-		__field(size_t, size)
-		__field(ino_t, ino)
-		__field(int, fd)
+		__string(	exp_name,		dmabuf->exp_name)
+		__field(	size_t,			size)
+		__field(	ino_t,			ino)
+		__field(	int,			fd)
 	),
 
 	TP_fast_assign(
 		__assign_str(exp_name);
-		__entry->size = dmabuf->size;
-		__entry->ino = dmabuf->file->f_inode->i_ino;
-		__entry->fd = fd;
+		__entry->size	= dmabuf->size;
+		__entry->ino	= dmabuf->file->f_inode->i_ino;
+		__entry->fd	= fd;
 	),
 
 	TP_printk("exp_name=%s size=%zu ino=%lu fd=%d",
@@ -137,11 +137,13 @@ DEFINE_EVENT(dma_buf_attach_dev, dma_buf_detach,
 	TP_ARGS(dmabuf, attach, is_dynamic, dev)
 );
 
-DEFINE_EVENT(dma_buf_fd, dma_buf_fd,
+DEFINE_EVENT_CONDITION(dma_buf_fd, dma_buf_fd,
 
 	TP_PROTO(struct dma_buf *dmabuf, int fd),
 
-	TP_ARGS(dmabuf, fd)
+	TP_ARGS(dmabuf, fd),
+
+	TP_CONDITION(fd >= 0)
 );
 
 DEFINE_EVENT(dma_buf_fd, dma_buf_get,