From 51b610b87d018e88fab7e6b1ad68e27e13d2dbf3 Mon Sep 17 00:00:00 2001
From: Vijayanand Jitta <vjitta@codeaurora.org>
Date: Thu, 25 Feb 2021 17:23:25 +0530
Subject: [PATCH] ANDROID: dma-buf: add get_each_dmabuf function

Add and export get_each_dmabuf function which helps in
traversing the db_list, this will be used by the minidump
module to get dmabuf info.

Bug: 181203151
Change-Id: Ie24788fcf9cf0a49316cb871dcb9191e8084ccde
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
---
 drivers/dma-buf/dma-buf.c | 24 ++++++++++++++++++++++++
 include/linux/dma-buf.h   |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 62e5ea655307..0ab865543d1f 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -38,6 +38,30 @@ struct dma_buf_list {
 
 static struct dma_buf_list db_list;
 
+/*
+ * This function helps in traversing the db_list and calls the
+ * callback function which can extract required info out of each
+ * dmabuf.
+ */
+int get_each_dmabuf(int (*callback)(const struct dma_buf *dmabuf,
+		    void *private), void *private)
+{
+	struct dma_buf *buf;
+	int ret = mutex_lock_interruptible(&db_list.lock);
+
+	if (ret)
+		return ret;
+
+	list_for_each_entry(buf, &db_list.head, list_node) {
+		ret = callback(buf, private);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&db_list.lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(get_each_dmabuf);
+
 static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen)
 {
 	struct dma_buf *dmabuf;
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 893301220f99..f1242b50f627 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -588,6 +588,8 @@ dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach)
 	return !!attach->importer_ops;
 }
 
+int get_each_dmabuf(int (*callback)(const struct dma_buf *dmabuf,
+		    void *private), void *private);
 int is_dma_buf_file(struct file *file);
 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
 					  struct device *dev);