[PATCH net v3 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.

bnge_adjust_pow_two() also sizes the RX, RX aggregation, TX and
completion ring pages. For the default 511-entry rings their page
counts do not change. The completion ring is sized from more than
the default depth, so its page count changes where the old code
dropped a partial page. With 8K ring pages, TPA off and the default
rings, its budget is 1533 entries and the page count goes from 2 to 4.
With 4K ring pages and TPA on, when the firmware reports a
max_aggs_supported of 260 to 387, it goes from 16 to 32.
In these cases the old completion ring held fewer entries than
its budget.

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_resc.h | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnge/bnge_resc.h b/drivers/net/ethernet/broadcom/bnge/bnge_resc.h
index b62a634669f6..c0b6992d7f82 100644
--- a/drivers/net/ethernet/broadcom/bnge/bnge_resc.h
+++ b/drivers/net/ethernet/broadcom/bnge/bnge_resc.h
@@ -81,13 +81,10 @@ bnge_adjust_pow_two(u32 total_ent, u16 ent_per_blk)
 {
 	u32 blks = total_ent / ent_per_blk;
 
-	if (blks == 0 || blks == 1)
-		return ++blks;
+	if (!blks)
+		return 1;
 
-	if (!is_power_of_2(blks))
-		blks = roundup_pow_of_two(blks);
-
-	return blks;
+	return roundup_pow_of_two(blks + 1);
 }
 
 #define BNGE_MAX_ROCE_MSIX		64
-- 
2.52.0