nfp: provide a better warning when ring allocation fails

NFP supports fairly enormous ring sizes (up to 256k descriptors).
In commit 466271703867 ("nfp: use kvcalloc() to allocate SW buffer
descriptor arrays") we have started using kvcalloc() functions to
make sure the allocation of software state arrays doesn't hit
the MAX_ORDER limit.  Unfortunately, we can't use virtual mappings
for the DMA region holding HW descriptors.  In case this allocation
fails instead of the generic (and fairly scary) warning/splat in
the logs print a helpful message explaining what happened and
suggesting how to fix it.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index 1aac55d..6dab45c 100644 (file)
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -2180,9 +2180,13 @@ nfp_net_tx_ring_alloc(struct nfp_net_dp *dp, struct nfp_net_tx_ring *tx_ring)
 
        tx_ring->size = array_size(tx_ring->cnt, sizeof(*tx_ring->txds));
        tx_ring->txds = dma_zalloc_coherent(dp->dev, tx_ring->size,
-                                           &tx_ring->dma, GFP_KERNEL);
-       if (!tx_ring->txds)
+                                           &tx_ring->dma,
+                                           GFP_KERNEL | __GFP_NOWARN);
+       if (!tx_ring->txds) {
+               netdev_warn(dp->netdev, "failed to allocate TX descriptor ring memory, requested descriptor count: %d, consider lowering descriptor count\n",
+                           tx_ring->cnt);
                goto err_alloc;
+       }
 
        tx_ring->txbufs = kvcalloc(tx_ring->cnt, sizeof(*tx_ring->txbufs),
                                   GFP_KERNEL);
@@ -2334,9 +2338,13 @@ nfp_net_rx_ring_alloc(struct nfp_net_dp *dp, struct nfp_net_rx_ring *rx_ring)
        rx_ring->cnt = dp->rxd_cnt;
        rx_ring->size = array_size(rx_ring->cnt, sizeof(*rx_ring->rxds));
        rx_ring->rxds = dma_zalloc_coherent(dp->dev, rx_ring->size,
-                                           &rx_ring->dma, GFP_KERNEL);
-       if (!rx_ring->rxds)
+                                           &rx_ring->dma,
+                                           GFP_KERNEL | __GFP_NOWARN);
+       if (!rx_ring->rxds) {
+               netdev_warn(dp->netdev, "failed to allocate RX descriptor ring memory, requested descriptor count: %d, consider lowering descriptor count\n",
+                           rx_ring->cnt);
                goto err_alloc;
+       }
 
        rx_ring->rxbufs = kvcalloc(rx_ring->cnt, sizeof(*rx_ring->rxbufs),
                                   GFP_KERNEL);