[PATCH net v2 2/2] bnge: fix RSS table sizing for large RX ring counts

[Vikas Gupta <vikas.gupta@broadcom.com>]

From: Dharmender Garg <dharmender.garg@broadcom.com>

bnge_adjust_pow_two() adds one block before rounding up to a power of
two only when the quotient is 0 or 1. A larger quotient that is
already a power of two is returned unchanged, so 129-192 RX rings
get a 128-entry RSS indirection table and 257-320 rings a 256-entry
one. The rings above the table size never receive default RSS traffic.
bnxt_calc_nr_ring_pages() always adds one, which is correct.

Make bnge_adjust_pow_two() always add one block before rounding up.
The same helper also sized the ring pages; to keep the ring size
calculation unchanged, move that to a separate bnge_calc_nr_ring_pages()
helper that retains the original rounding.

Fixes: 627c67f038d2 ("bng_en: Add resource management support")
Signed-off-by: Dharmender Garg <dharmender.garg@broadcom.com>
Reviewed-by: Vikas Gupta <vikas.gupta@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnge/bnge_netdev.c | 10 +++++-----
 drivers/net/ethernet/broadcom/bnge/bnge_resc.h   | 11 +++++++++++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c b/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c
index a4288f0258f8..ecba8aff3052 100644
--- a/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c
+++ b/drivers/net/ethernet/broadcom/bnge/bnge_netdev.c
@@ -3339,8 +3339,8 @@ void bnge_set_ring_params(struct bnge_dev *bd)
 		}
 		agg_ring_size = ring_size * agg_factor;
 
-		bn->rx_agg_nr_pages = bnge_adjust_pow_two(agg_ring_size,
-							  RX_DESC_CNT);
+		bn->rx_agg_nr_pages = bnge_calc_nr_ring_pages(agg_ring_size,
+							      RX_DESC_CNT);
 		if (bn->rx_agg_nr_pages > MAX_RX_AGG_PAGES) {
 			u32 tmp = agg_ring_size;
 
@@ -3363,11 +3363,11 @@ void bnge_set_ring_params(struct bnge_dev *bd)
 	bn->rx_buf_use_size = rx_size;
 	bn->rx_buf_size = rx_space;
 
-	bn->rx_nr_pages = bnge_adjust_pow_two(ring_size, RX_DESC_CNT);
+	bn->rx_nr_pages = bnge_calc_nr_ring_pages(ring_size, RX_DESC_CNT);
 	bn->rx_ring_mask = (bn->rx_nr_pages * RX_DESC_CNT) - 1;
 
 	ring_size = bn->tx_ring_size;
-	bn->tx_nr_pages = bnge_adjust_pow_two(ring_size, TX_DESC_CNT);
+	bn->tx_nr_pages = bnge_calc_nr_ring_pages(ring_size, TX_DESC_CNT);
 	bn->tx_ring_mask = (bn->tx_nr_pages * TX_DESC_CNT) - 1;
 
 	max_rx_cmpl = bn->rx_ring_size;
@@ -3377,7 +3377,7 @@ void bnge_set_ring_params(struct bnge_dev *bd)
 	ring_size = max_rx_cmpl * 2 + agg_ring_size + bn->tx_ring_size;
 	bn->cp_ring_size = ring_size;
 
-	bn->cp_nr_pages = bnge_adjust_pow_two(ring_size, CP_DESC_CNT);
+	bn->cp_nr_pages = bnge_calc_nr_ring_pages(ring_size, CP_DESC_CNT);
 	if (bn->cp_nr_pages > MAX_CP_PAGES) {
 		bn->cp_nr_pages = MAX_CP_PAGES;
 		bn->cp_ring_size = MAX_CP_PAGES * CP_DESC_CNT - 1;
diff --git a/drivers/net/ethernet/broadcom/bnge/bnge_resc.h b/drivers/net/ethernet/broadcom/bnge/bnge_resc.h
index b62a634669f6..58462524939f 100644
--- a/drivers/net/ethernet/broadcom/bnge/bnge_resc.h
+++ b/drivers/net/ethernet/broadcom/bnge/bnge_resc.h
@@ -81,6 +81,17 @@ bnge_adjust_pow_two(u32 total_ent, u16 ent_per_blk)
 {
 	u32 blks = total_ent / ent_per_blk;
 
+	if (!blks)
+		return 1;
+
+	return roundup_pow_of_two(blks + 1);
+}
+
+static inline u32
+bnge_calc_nr_ring_pages(u32 total_ent, u16 ent_per_blk)
+{
+	u32 blks = total_ent / ent_per_blk;
+
 	if (blks == 0 || blks == 1)
 		return ++blks;
 
-- 
2.52.0