net: ena: Use dev_alloc() in RX buffer allocation

Use dev_alloc() when allocating RX buffers instead of specifying the
allocation flags explicitly. This result in same behaviour with less
code.

Also move the page allocation and its DMA mapping into a function. This
creates a logical block, which may help understanding the code.
Signed-off-by: NShay Agroskin <shayagr@amazon.com>
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/amazon/ena/ena_netdev.c

@@ -975,8 +975,37 @@ static void ena_free_all_io_rx_resources(struct ena_adapter *adapter)
 		ena_free_rx_resources(adapter, i);
 }
 
-static int ena_alloc_rx_page(struct ena_ring *rx_ring,
-				    struct ena_rx_buffer *rx_info, gfp_t gfp)
+struct page *ena_alloc_map_page(struct ena_ring *rx_ring, dma_addr_t *dma)
+{
+	struct page *page;
+
+	/* This would allocate the page on the same NUMA node the executing code
+	 * is running on.
+	 */
+	page = dev_alloc_page();
+	if (!page) {
+		ena_increase_stat(&rx_ring->rx_stats.page_alloc_fail, 1,
+				  &rx_ring->syncp);
+		return ERR_PTR(-ENOSPC);
+	}
+
+	/* To enable NIC-side port-mirroring, AKA SPAN port,
+	 * we make the buffer readable from the nic as well
+	 */
+	*dma = dma_map_page(rx_ring->dev, page, 0, ENA_PAGE_SIZE,
+			    DMA_BIDIRECTIONAL);
+	if (unlikely(dma_mapping_error(rx_ring->dev, *dma))) {
+		ena_increase_stat(&rx_ring->rx_stats.dma_mapping_err, 1,
+				  &rx_ring->syncp);
+		__free_page(page);
+		return ERR_PTR(-EIO);
+	}
+
+	return page;
+}
+
+static int ena_alloc_rx_buffer(struct ena_ring *rx_ring,
+			       struct ena_rx_buffer *rx_info)
 {
 	int headroom = rx_ring->rx_headroom;
 	struct ena_com_buf *ena_buf;
@@ -991,25 +1020,11 @@ static int ena_alloc_rx_page(struct ena_ring *rx_ring,
 	if (unlikely(rx_info->page))
 		return 0;
 
-	page = alloc_page(gfp);
-	if (unlikely(!page)) {
-		ena_increase_stat(&rx_ring->rx_stats.page_alloc_fail, 1,
-				  &rx_ring->syncp);
-		return -ENOMEM;
-	}
-
-	/* To enable NIC-side port-mirroring, AKA SPAN port,
-	 * we make the buffer readable from the nic as well
-	 */
-	dma = dma_map_page(rx_ring->dev, page, 0, ENA_PAGE_SIZE,
-			   DMA_BIDIRECTIONAL);
-	if (unlikely(dma_mapping_error(rx_ring->dev, dma))) {
-		ena_increase_stat(&rx_ring->rx_stats.dma_mapping_err, 1,
-				  &rx_ring->syncp);
+	/* We handle DMA here */
+	page = ena_alloc_map_page(rx_ring, &dma);
+	if (unlikely(IS_ERR(page)))
+		return PTR_ERR(page);
 
-		__free_page(page);
-		return -EIO;
-	}
 	netif_dbg(rx_ring->adapter, rx_status, rx_ring->netdev,
 		  "Allocate page %p, rx_info %p\n", page, rx_info);
 
@@ -1065,8 +1080,7 @@ static int ena_refill_rx_bufs(struct ena_ring *rx_ring, u32 num)
 
 		rx_info = &rx_ring->rx_buffer_info[req_id];
 
-		rc = ena_alloc_rx_page(rx_ring, rx_info,
-				       GFP_ATOMIC | __GFP_COMP);
+		rc = ena_alloc_rx_buffer(rx_ring, rx_info);
 		if (unlikely(rc < 0)) {
 			netif_warn(rx_ring->adapter, rx_err, rx_ring->netdev,
 				   "Failed to allocate buffer for rx queue %d\n",