linux-kernel - [PATCH net-next 1/2] i40e: remove dead stores on XSK hotpath

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-next>] [day] [month] [year] [list]

Message-Id: <20211130183649.1166842-1-alexandr.lobakin@intel.com>
Date:   Tue, 30 Nov 2021 19:36:48 +0100
From:   Alexander Lobakin <alexandr.lobakin@...el.com>
To:     intel-wired-lan@...ts.osuosl.org
Cc:     Alexander Lobakin <alexandr.lobakin@...el.com>,
        Tony Nguyen <anthony.l.nguyen@...el.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        Magnus Karlsson <magnus.karlsson@...el.com>,
        Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        Cristian Dumitrescu <cristian.dumitrescu@...el.com>,
        bpf@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH net-next 1/2] i40e: remove dead stores on XSK hotpath

The 'if (ntu == rx_ring->count)' block in i40e_alloc_rx_buffers_zc()
was previously residing in the loop, but after introducing the
batched interface it is used only to wrap-around the NTU descriptor,
thus no more need to assign 'xdp'.

'cleaned_count' in i40e_clean_rx_irq_zc() was previously being
incremented in the loop, but after commit f12738b6ec06
("i40e: remove unnecessary cleaned_count updates") it gets
assigned only once after it, so the initialization can be dropped.

Fixes: 6aab0bb0c5cd ("i40e: Use the xsk batched rx allocation interface")
Fixes: f12738b6ec06 ("i40e: remove unnecessary cleaned_count updates")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@...el.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
---
 drivers/net/ethernet/intel/i40e/i40e_xsk.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index ea06e957393e..f08d19b8c554 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -218,7 +218,6 @@ bool i40e_alloc_rx_buffers_zc(struct i40e_ring *rx_ring, u16 count)
 	ntu += nb_buffs;
 	if (ntu == rx_ring->count) {
 		rx_desc = I40E_RX_DESC(rx_ring, 0);
-		xdp = i40e_rx_bi(rx_ring, 0);
 		ntu = 0;
 	}
 
@@ -324,11 +323,11 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
 int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 {
 	unsigned int total_rx_bytes = 0, total_rx_packets = 0;
-	u16 cleaned_count = I40E_DESC_UNUSED(rx_ring);
 	u16 next_to_clean = rx_ring->next_to_clean;
 	u16 count_mask = rx_ring->count - 1;
 	unsigned int xdp_res, xdp_xmit = 0;
 	bool failure = false;
+	u16 cleaned_count;
 
 	while (likely(total_rx_packets < (unsigned int)budget)) {
 		union i40e_rx_desc *rx_desc;
-- 
2.33.1