On Mon,  5 Aug 2024 21:25:17 +0000 Mina Almasry wrote:

+struct net_iov *
+net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
+{
+	struct dmabuf_genpool_chunk_owner *owner;
+	unsigned long dma_addr;
+	struct net_iov *niov;
+	ssize_t offset;
+	ssize_t index;
+
+	dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE,
+					(void **)&owner);
+	if (!dma_addr)
+		return NULL;
+
+	offset = dma_addr - owner->base_dma_addr;
+	index = offset / PAGE_SIZE;
+	niov = &owner->niovs[index];
+
+	niov->dma_addr = 0;

Is the dma_addr not constant for a given niov for the entire lifetime
of the binding? Why flip it back and forth between its value and 0?