diff mbox

[RFC,v1,2/2] dma-buf: add lock callback for fcntl system call

Message ID 1373609566-10784-3-git-send-email-inki.dae@samsung.com (mailing list archive)
State RFC, archived
Headers

Commit Message

Inki Dae July 12, 2013, 6:12 a.m. UTC 
  This patch adds lock callback to dma buf file operations,
and this callback will be called by fcntl system call.

With this patch, fcntl system call can be used for buffer
synchronization between CPU and CPU, and CPU and DMA in user mode.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/base/dma-buf.c |   33 +++++++++++++++++++++++++++++++++
 1 files changed, 33 insertions(+), 0 deletions(-)
diff mbox

Patch

diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 9a26981..e1b8583 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -80,9 +80,42 @@  static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
 	return dmabuf->ops->mmap(dmabuf, vma);
 }
 
+static int dma_buf_lock(struct file *file, int cmd, struct file_lock *fl)
+{
+	struct dma_buf *dmabuf;
+	unsigned int type;
+	bool wait = false;
+
+	if (!is_dma_buf_file(file))
+		return -EINVAL;
+
+	dmabuf = file->private_data;
+
+	if ((fl->fl_type & F_UNLCK) == F_UNLCK) {
+		dmabuf_sync_single_unlock(dmabuf);
+		return 0;
+	}
+
+	/* convert flock type to dmabuf sync type. */
+	if ((fl->fl_type & F_WRLCK) == F_WRLCK)
+		type = DMA_BUF_ACCESS_W;
+	else if ((fl->fl_type & F_RDLCK) == F_RDLCK)
+		type = DMA_BUF_ACCESS_R;
+	else
+		return -EINVAL;
+
+	if (fl->fl_flags & FL_SLEEP)
+		wait = true;
+
+	/* TODO. the locking to certain region should also be considered. */
+
+	return dmabuf_sync_single_lock(dmabuf, type, wait);
+}
+
 static const struct file_operations dma_buf_fops = {
 	.release	= dma_buf_release,
 	.mmap		= dma_buf_mmap_internal,
+	.lock		= dma_buf_lock,
 };
 
 /*