Hi Laurent, Thanks for review.
On 04/06/2012 05:12 PM, Laurent Pinchart wrote:
Hi Tomasz,
On Thursday 05 April 2012 16:00:08 Tomasz Stanislawski wrote:
From: Sumit Semwal sumit.semwal@ti.com
This patch makes changes for adding dma-contig as a dma_buf user. It provides function implementations for the {attach, detach, map, unmap}_dmabuf() mem_ops of DMABUF memory type.
Signed-off-by: Sumit Semwal sumit.semwal@ti.com Signed-off-by: Sumit Semwal sumit.semwal@linaro.org [author of the original patch] Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com [integration with refactored dma-contig allocator]
drivers/media/video/videobuf2-dma-contig.c | 117 +++++++++++++++++++++++++ 1 files changed, 117 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index 30f316588..6329483 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -10,6 +10,7 @@
- the Free Software Foundation.
*/
+#include <linux/dma-buf.h> #include <linux/module.h> #include <linux/scatterlist.h> #include <linux/sched.h> @@ -33,6 +34,9 @@ struct vb2_dc_buf {
/* USERPTR related */ struct vm_area_struct *vma;
- /* DMABUF related */
- struct dma_buf_attachment *db_attach;
};
/*********************************************/ @@ -425,6 +429,115 @@ fail_buf: }
/*********************************************/ +/* callbacks for DMABUF buffers */ +/*********************************************/
+static int vb2_dc_map_dmabuf(void *mem_priv) +{
- struct vb2_dc_buf *buf = mem_priv;
- struct sg_table *sgt;
- unsigned long contig_size;
- int ret = 0;
- if (WARN_ON(!buf->db_attach)) {
printk(KERN_ERR "trying to pin a non attached buffer\n");return -EINVAL;- }
- if (WARN_ON(buf->dma_sgt)) {
printk(KERN_ERR "dmabuf buffer is already pinned\n");return 0;- }
- /* get the associated scatterlist for this buffer */
- sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
- if (IS_ERR_OR_NULL(sgt)) {
printk(KERN_ERR "Error getting dmabuf scatterlist\n");return -EINVAL;- }
- /* checking if dmabuf is big enough to store contiguous chunk */
- contig_size = vb2_dc_get_contiguous_size(sgt);
- if (contig_size < buf->size) {
printk(KERN_ERR "contiguous chunk of dmabuf is too small\n");ret = -EFAULT;goto fail_map;The fail_map label is only used here, you can move the dma_buf_unmap_attachment() call here and return -EFAULT directly.
Patch "[RFC 07/13] v4l: vb2-dma-contig: change map/unmap behaviour for importers" introduces other cleanup labels. Anyway I will remove this redundant label as you proposed.
- }
- buf->dma_addr = sg_dma_address(sgt->sgl);
- buf->dma_sgt = sgt;
- return 0;
+fail_map:
- dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
- return ret;
+}
+static void vb2_dc_unmap_dmabuf(void *mem_priv) +{
- struct vb2_dc_buf *buf = mem_priv;
- struct sg_table *sgt = buf->dma_sgt;
- if (WARN_ON(!buf->db_attach)) {
printk(KERN_ERR "trying to unpin a not attached buffer\n");return;- }
- if (WARN_ON(!sgt)) {
printk(KERN_ERR "dmabuf buffer is already unpinned\n");return;- }
- dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
- buf->dma_addr = 0;
- buf->dma_sgt = NULL;
+}
+static void vb2_dc_detach_dmabuf(void *mem_priv) +{
- struct vb2_dc_buf *buf = mem_priv;
- if (buf->dma_addr)
vb2_dc_unmap_dmabuf(buf);What would you think about calling vb2_dc_unmap_dmabuf() from vb2 core instead, to keep the map/unmap calls symmetrical (the second WARN_ON and the related printk in vb2_dc_unmap_dmabuf() might need to go then) ?
Detach without unmap may happen in a case of closing a video fd without prior dequeuing of all buffers.
A call map_dmabuf should be moved to __enqueue_in_driver and add calling unmap_dmabuf to vb2_buffer_done in order to keep map/unmap calls symmetrical. I'll check if this could work.
Regards, Tomasz Stanislawski