netdev - [PATCH net-next v2 01/10] nfp: calculate ring masks without conditionals

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 21 Mar 2022 11:42:00 +0100
From:   Simon Horman <simon.horman@...igine.com>
To:     David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     Yinjun Zhang <yinjun.zhang@...igine.com>, netdev@...r.kernel.org,
        oss-drivers@...igine.com
Subject: [PATCH net-next v2 01/10] nfp: calculate ring masks without conditionals

From: Jakub Kicinski <jakub.kicinski@...ronome.com>

Ring enable masks are 64bit long.  Replace mask calculation from:
  block_cnt == 64 ? 0xffffffffffffffffULL : (1 << block_cnt) - 1
with:
  (U64_MAX >> (64 - block_cnt))
to simplify the code.

Signed-off-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
Signed-off-by: Fei Qin <fei.qin@...igine.com>
Signed-off-by: Simon Horman <simon.horman@...igine.com>
---
 drivers/net/ethernet/netronome/nfp/nfp_net_common.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index ef8645b77e79..50f7ada0dedd 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -2959,11 +2959,11 @@ static int nfp_net_set_config_and_enable(struct nfp_net *nn)
 	for (r = 0; r < nn->dp.num_rx_rings; r++)
 		nfp_net_rx_ring_hw_cfg_write(nn, &nn->dp.rx_rings[r], r);
 
-	nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE, nn->dp.num_tx_rings == 64 ?
-		  0xffffffffffffffffULL : ((u64)1 << nn->dp.num_tx_rings) - 1);
+	nn_writeq(nn, NFP_NET_CFG_TXRS_ENABLE,
+		  U64_MAX >> (64 - nn->dp.num_tx_rings));
 
-	nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE, nn->dp.num_rx_rings == 64 ?
-		  0xffffffffffffffffULL : ((u64)1 << nn->dp.num_rx_rings) - 1);
+	nn_writeq(nn, NFP_NET_CFG_RXRS_ENABLE,
+		  U64_MAX >> (64 - nn->dp.num_rx_rings));
 
 	if (nn->dp.netdev)
 		nfp_net_write_mac_addr(nn, nn->dp.netdev->dev_addr);
-- 
2.30.2