[PATCH net-next 2/5] bnxt_en: Resize RSS contexts on channel count change

["Björn Töpel" <bjorn@kernel.org>]

bnxt_set_channels() rejects channel changes that alter the RSS table
size when IFF_RXFH_CONFIGURED is set, because non-default context
sizes were locked at creation.

Replace the rejection with the new resize helpers. All validation runs
before any mutation:

 1. ethtool_rxfh_indir_can_resize() checks context 0.
 2. ethtool_rxfh_contexts_resize_all() validates and resizes
    all non-default contexts (all-or-none).
 3. ethtool_rxfh_indir_resize() applies context 0 changes.

When context 0 uses defaults (!IFF_RXFH_CONFIGURED), steps 1 and 3 are
skipped; the driver regenerates the table via
bnxt_set_dflt_rss_indir_tbl().

Signed-off-by: Björn Töpel <bjorn@kernel.org>
---
 .../net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 23 +++++++++++++++----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
index 26fcd52c8a61..7608e5d95630 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
@@ -977,11 +977,24 @@ static int bnxt_set_channels(struct net_device *dev,
 		tx_xdp = req_rx_rings;
 	}
 
-	if (bnxt_get_nr_rss_ctxs(bp, req_rx_rings) !=
-	    bnxt_get_nr_rss_ctxs(bp, bp->rx_nr_rings) &&
-	    netif_is_rxfh_configured(dev)) {
-		netdev_warn(dev, "RSS table size change required, RSS table entries must be default to proceed\n");
-		return -EINVAL;
+	if (bnxt_get_nr_rss_ctxs(bp, req_rx_rings) != bnxt_get_nr_rss_ctxs(bp, bp->rx_nr_rings)) {
+		u32 new_size = bnxt_get_nr_rss_ctxs(bp, req_rx_rings) * BNXT_RSS_TABLE_ENTRIES_P5;
+		u32 old_size = bnxt_get_rxfh_indir_size(dev);
+
+		/* Validate context 0 can be resized before mutating anything */
+		if (netif_is_rxfh_configured(dev) &&
+		    ethtool_rxfh_indir_can_resize(bp->rss_indir_tbl, old_size, new_size)) {
+			netdev_warn(dev, "RSS table size change not supported with current indirection table\n");
+			return -EINVAL;
+		}
+
+		rc = ethtool_rxfh_contexts_resize_all(dev, new_size);
+		if (rc)
+			return rc;
+
+		/* All validated; apply context 0 resize */
+		if (netif_is_rxfh_configured(dev))
+			ethtool_rxfh_indir_resize(bp->rss_indir_tbl, old_size, new_size);
 	}
 
 	rc = bnxt_check_rings(bp, req_tx_rings, req_rx_rings, sh, tcs, tx_xdp);
-- 
2.53.0