On Mon, Jul 05, 2021 at 04:03:14PM +0300, Oded Gabbay wrote:

• rc = sg_alloc_table(*sgt, nents, GFP_KERNEL | __GFP_ZERO);
• if (rc)

• goto error_free;
  

If you are not going to include a CPU list then I suggest setting sg_table->orig_nents == 0

And using only the nents which is the length of the DMA list.

At least it gives some hope that other parts of the system could detect this.

• /* Merge pages and put them into the scatterlist */
• cur_page = 0;
• for_each_sgtable_sg((*sgt), sg, i) {

for_each_sgtable_sg should never be used when working with sg_dma_address() type stuff, here and everywhere else. The DMA list should be iterated using the for_each_sgtable_dma_sg() macro.

• /* In case we got a large memory area to export, we need to divide it

• * to smaller areas because each entry in the dmabuf sgt can only
  

• * describe unsigned int.
  

• */
  

Huh? This is forming a SGL, it should follow the SGL rules which means you have to fragment based on the dma_get_max_seg_size() of the importer device.

• hl_dmabuf->pages = kcalloc(hl_dmabuf->npages, sizeof(*hl_dmabuf->pages),

• 						GFP_KERNEL);
  

• if (!hl_dmabuf->pages) {

• rc = -ENOMEM;
  

• goto err_free_dmabuf_wrapper;
  

• }

Why not just create the SGL directly? Is there a reason it needs to make a page list?

Jason