[PATCH] dma-buf: support users to change dma_buf.name

Signed-off-by: Guangming Cao <redacted>
---
  drivers/dma-buf/dma-buf.c | 28 ++++++++++++++++++++++------
  include/linux/dma-buf.h   |  1 +
  2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 511fe0d217a0..949af232c644 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c

@@ -331,20 +331,20 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
   * purpose between different devices.
   *
   * @dmabuf: [in]     dmabuf buffer that will be renamed.
- * @buf:    [in]     A piece of userspace memory that contains the name of
+ * @buf:    [in]     A piece of memory that contains the name of
   *                   the dma-buf.
   *
   * Returns 0 on success. If the dma-buf buffer is already attached to
   * devices, return -EBUSY.
   *
   */
-static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
+long dma_buf_set_name(struct dma_buf *dmabuf, const char *buf)
  {
-	char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
+	char *name = kstrndup(buf, DMA_BUF_NAME_LEN, GFP_KERNEL);
  	long ret = 0;
  
-	if (IS_ERR(name))
-		return PTR_ERR(name);
+	if (!name)
+		return -ENOMEM;
  
  	dma_resv_lock(dmabuf->resv, NULL);
  	if (!list_empty(&dmabuf->attachments)) {

@@ -361,6 +361,22 @@ static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
  	dma_resv_unlock(dmabuf->resv);
  	return ret;
  }
+EXPORT_SYMBOL_GPL(dma_buf_set_name);
+
+static long
+dma_buf_set_name_user(struct dma_buf *dmabuf, const char __user *buf)
+{
+	char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
+	long ret = 0;
+
+	if (IS_ERR(name))
+		return PTR_ERR(name);
+
+	ret = dma_buf_set_name(dmabuf, name);
+	kfree(name);
+
+	return ret;
+}
  
  static long dma_buf_ioctl(struct file *file,
  			  unsigned int cmd, unsigned long arg)

@@ -403,7 +419,7 @@ static long dma_buf_ioctl(struct file *file,
  
  	case DMA_BUF_SET_NAME_A:
  	case DMA_BUF_SET_NAME_B:
-		return dma_buf_set_name(dmabuf, (const char __user *)arg);
+		return dma_buf_set_name_user(dmabuf, (const char __user *)arg);
  
  	default:
  		return -ENOTTY;

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index efdc56b9d95f..e6612ab59a59 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h

@@ -507,4 +507,5 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
  		 unsigned long);
  int dma_buf_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map);
  void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map);
+long dma_buf_set_name(struct dma_buf *dmabuf, const char *name);
  #endif /* __DMA_BUF_H__ */