gve: Fix GFP flags when allocing pages

Use GFP_ATOMIC when allocating pages out of the hotpath,
continue to use GFP_KERNEL when allocating pages during setup.

GFP_KERNEL will allow blocking which allows it to succeed
more often in a low memory enviornment but in the hotpath we do
not want to allow the allocation to block.

Fixes: f5cedc84a3 ("gve: Add transmit and receive support")
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Link: https://lore.kernel.org/r/20220126003843.3584521-1-awogbemila@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/google/gve/gve.h

@@ -843,7 +843,7 @@ static inline bool gve_is_gqi(struct gve_priv *priv)
 /* buffers */
 int gve_alloc_page(struct gve_priv *priv, struct device *dev,
 		   struct page **page, dma_addr_t *dma,
-		   enum dma_data_direction);
+		   enum dma_data_direction, gfp_t gfp_flags);
 void gve_free_page(struct device *dev, struct page *page, dma_addr_t dma,
 		   enum dma_data_direction);
 /* tx handling */

drivers/net/ethernet/google/gve/gve_main.c

@@ -766,9 +766,9 @@ static void gve_free_rings(struct gve_priv *priv)
 
 int gve_alloc_page(struct gve_priv *priv, struct device *dev,
 		   struct page **page, dma_addr_t *dma,
-		   enum dma_data_direction dir)
+		   enum dma_data_direction dir, gfp_t gfp_flags)
 {
-	*page = alloc_page(GFP_KERNEL);
+	*page = alloc_page(gfp_flags);
 	if (!*page) {
 		priv->page_alloc_fail++;
 		return -ENOMEM;
@@ -811,7 +811,7 @@ static int gve_alloc_queue_page_list(struct gve_priv *priv, u32 id,
 	for (i = 0; i < pages; i++) {
 		err = gve_alloc_page(priv, &priv->pdev->dev, &qpl->pages[i],
 				     &qpl->page_buses[i],
-				     gve_qpl_dma_dir(priv, id));
+				     gve_qpl_dma_dir(priv, id), GFP_KERNEL);
 		/* caller handles clean up */
 		if (err)
 			return -ENOMEM;

drivers/net/ethernet/google/gve/gve_rx.c

@@ -86,7 +86,8 @@ static int gve_rx_alloc_buffer(struct gve_priv *priv, struct device *dev,
 	dma_addr_t dma;
 	int err;
 
-	err = gve_alloc_page(priv, dev, &page, &dma, DMA_FROM_DEVICE);
+	err = gve_alloc_page(priv, dev, &page, &dma, DMA_FROM_DEVICE,
+			     GFP_ATOMIC);
 	if (err)
 		return err;
 

drivers/net/ethernet/google/gve/gve_rx_dqo.c

@@ -157,7 +157,7 @@ static int gve_alloc_page_dqo(struct gve_priv *priv,
 	int err;
 
 	err = gve_alloc_page(priv, &priv->pdev->dev, &buf_state->page_info.page,
-			     &buf_state->addr, DMA_FROM_DEVICE);
+			     &buf_state->addr, DMA_FROM_DEVICE, GFP_KERNEL);
 	if (err)
 		return err;