Re: [net-next v1 08/16] memory-provider: dmabuf devmem memory provider

On Thu, 7 Dec 2023 16:52:39 -0800, Mina Almasry wrote: <...>

+static int mp_dmabuf_devmem_init(struct page_pool *pool) +{

• struct netdev_dmabuf_binding *binding = pool->mp_priv;
• if (!binding)

• return -EINVAL;
  

• if (!(pool->p.flags & PP_FLAG_DMA_MAP))

• return -EOPNOTSUPP;
  

• if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)

• return -EOPNOTSUPP;
  

• netdev_dmabuf_binding_get(binding);
• return 0;

+}

+static struct page *mp_dmabuf_devmem_alloc_pages(struct page_pool *pool,

• 				 gfp_t gfp)
  

+{

• struct netdev_dmabuf_binding *binding = pool->mp_priv;
• struct page_pool_iov *ppiov;
• ppiov = netdev_alloc_dmabuf(binding);

Since it only supports one-page allocation, we'd better add a check in `ops->init()` that `pool->p.order` must be 0.

• if (!ppiov)

• return NULL;
  

• ppiov->pp = pool;
• pool->pages_state_hold_cnt++;
• trace_page_pool_state_hold(pool, (struct page *)ppiov,

• 		   pool->pages_state_hold_cnt);
  

• return (struct page *)((unsigned long)ppiov | PP_IOV);

+}

<...>