[RFC PATCH v2 21/25] net/gve: Use GFP_KERNEL when pre-filling RX rings

[Luigi Rizzo]

When pre-filling DQO and GQI RX rings in process context before NAPI is
enabled (e.g. gve_open), use GFP_KERNEL instead of GFP_ATOMIC so page
allocation (and CoCo page decryption) can sleep instead of dipping into
atomic reserves.

Signed-off-by: Luigi Rizzo <lrizzo@xxxxxxxxxx>
---
 drivers/net/ethernet/google/gve/gve_buffer_mgmt_dqo.c | 7 ++++++-
 drivers/net/ethernet/google/gve/gve_rx.c              | 8 ++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve_buffer_mgmt_dqo.c b/drivers/net/ethernet/google/gve/gve_buffer_mgmt_dqo.c
index 6880d1531ba5e..3b13aa4999ae5 100644
--- a/drivers/net/ethernet/google/gve/gve_buffer_mgmt_dqo.c
+++ b/drivers/net/ethernet/google/gve/gve_buffer_mgmt_dqo.c
@@ -223,13 +223,18 @@ void gve_free_to_page_pool(struct gve_rx_ring *rx,
 static int gve_alloc_from_page_pool(struct gve_rx_ring *rx,
 				    struct gve_rx_buf_state_dqo *buf_state)
 {
+	/*
+	 * Use GFP_KERNEL when pre-filling RX rings in process context (e.g.
+	 * gve_open) so PISA metadata init and CoCo page decryption can sleep.
+	 */
+	gfp_t gfp = gve_get_napi_enabled(rx->gve) ? GFP_ATOMIC : GFP_KERNEL;
 	netmem_ref netmem;
 
 	buf_state->page_info.buf_size = rx->packet_buffer_truesize;
 	netmem = page_pool_alloc_netmem(rx->dqo.page_pool,
 					&buf_state->page_info.page_offset,
 					&buf_state->page_info.buf_size,
-					GFP_ATOMIC);
+					gfp);
 
 	if (!netmem)
 		return -ENOMEM;
diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c
index 81ea800e66e94..89f287b678bf0 100644
--- a/drivers/net/ethernet/google/gve/gve_rx.c
+++ b/drivers/net/ethernet/google/gve/gve_rx.c
@@ -161,12 +161,16 @@ static int gve_rx_alloc_buffer(struct gve_priv *priv, struct device *dev,
 			       union gve_rx_data_slot *data_slot,
 			       struct gve_rx_ring *rx)
 {
+	/*
+	 * Use GFP_KERNEL when pre-filling RX rings in process context (e.g.
+	 * gve_open) so PISA metadata init and CoCo page decryption can sleep.
+	 */
+	gfp_t gfp = gve_get_napi_enabled(priv) ? GFP_ATOMIC : GFP_KERNEL;
 	struct page *page;
 	dma_addr_t dma;
 	int err;
 
-	err = gve_alloc_page(priv, dev, &page, &dma, DMA_FROM_DEVICE,
-			     GFP_ATOMIC);
+	err = gve_alloc_page(priv, dev, &page, &dma, DMA_FROM_DEVICE, gfp);
 	if (err) {
 		u64_stats_update_begin(&rx->statss);
 		rx->rx_buf_alloc_fail++;
-- 
2.56.0.542.g3ef89b7020-goog