| 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
| ||
|
Message-ID:
<MN0PR12MB595376E110FB44EEBCF9C7C3B79E2@MN0PR12MB5953.namprd12.prod.outlook.com>
Date: Fri, 6 Sep 2024 17:44:23 +0000
From: "Pandey, Radhey Shyam" <radhey.shyam.pandey@....com>
To: Sean Anderson <sean.anderson@...ux.dev>, "David S . Miller"
<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski
<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, "netdev@...r.kernel.org"
<netdev@...r.kernel.org>
CC: "Simek, Michal" <michal.simek@....com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
<linux-kernel@...r.kernel.org>, Andy Chiu <andy.chiu@...ive.com>, Daniel
Borkmann <daniel@...earbox.net>, "Gupta, Suraj" <Suraj.Gupta2@....com>,
"Katakam, Harini" <harini.katakam@....com>
Subject: RE: [PATCH net v2] net: xilinx: axienet: Fix packet counting
> -----Original Message-----
> From: Sean Anderson <sean.anderson@...ux.dev>
> Sent: Friday, September 6, 2024 10:12 PM
> To: Pandey, Radhey Shyam <radhey.shyam.pandey@....com>; David S .
> Miller <davem@...emloft.net>; Eric Dumazet <edumazet@...gle.com>;
> Jakub Kicinski <kuba@...nel.org>; Paolo Abeni <pabeni@...hat.com>;
> netdev@...r.kernel.org
> Cc: Simek, Michal <michal.simek@....com>; linux-arm-
> kernel@...ts.infradead.org; linux-kernel@...r.kernel.org; Andy Chiu
> <andy.chiu@...ive.com>; Daniel Borkmann <daniel@...earbox.net>; Sean
> Anderson <sean.anderson@...ux.dev>
> Subject: [PATCH net v2] net: xilinx: axienet: Fix packet counting
>
> axienet_free_tx_chain returns the number of DMA descriptors it's
> handled. However, axienet_tx_poll treats the return as the number of
> packets. When scatter-gather SKBs are enabled, a single packet may use
> multiple DMA descriptors, which causes incorrect packet counts. Fix this
> by explicitly keepting track of the number of packets processed as
> separate from the DMA descriptors.
>
> Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet
Isn't it Fixes: 9e2bc267e780 ("net: axienet: Use NAPI for TX completion path")?
> driver")
> Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
+ Harini, Suraj to review and run this patch to ensure data path sanity.
> ---
>
> Changes in v2:
> - Only call napi_consume_skb with non-zero budget when force is false
>
> .../net/ethernet/xilinx/xilinx_axienet_main.c | 31 +++++++++++--------
> 1 file changed, 18 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index 9aeb7b9f3ae4..556033849d55 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -670,21 +670,21 @@ static int axienet_device_reset(struct net_device
> *ndev)
> * @force: Whether to clean descriptors even if not complete
> * @sizep: Pointer to a u32 filled with the total sum of all bytes
> * in all cleaned-up descriptors. Ignored if NULL.
> - * @budget: NAPI budget (use 0 when not called from NAPI poll)
> + * @budget: NAPI budget (use INT_MAX when not called from NAPI poll)
> *
> * Would either be called after a successful transmit operation, or after
> * there was an error when setting up the chain.
> - * Returns the number of descriptors handled.
> + * Returns the number of packets handled.
> */
> static int axienet_free_tx_chain(struct axienet_local *lp, u32 first_bd,
> int nr_bds, bool force, u32 *sizep, int
> budget)
> {
> struct axidma_bd *cur_p;
> unsigned int status;
> + int i, packets = 0;
> dma_addr_t phys;
> - int i;
>
> - for (i = 0; i < nr_bds; i++) {
> + for (i = 0; i < nr_bds && packets < budget; i++) {
> cur_p = &lp->tx_bd_v[(first_bd + i) % lp->tx_bd_num];
> status = cur_p->status;
>
> @@ -701,8 +701,10 @@ static int axienet_free_tx_chain(struct axienet_local
> *lp, u32 first_bd,
> (cur_p->cntrl &
> XAXIDMA_BD_CTRL_LENGTH_MASK),
> DMA_TO_DEVICE);
>
> - if (cur_p->skb && (status &
> XAXIDMA_BD_STS_COMPLETE_MASK))
> - napi_consume_skb(cur_p->skb, budget);
> + if (cur_p->skb && (status &
> XAXIDMA_BD_STS_COMPLETE_MASK)) {
> + napi_consume_skb(cur_p->skb, force ? 0 : budget);
> + packets++;
> + }
>
> cur_p->app0 = 0;
> cur_p->app1 = 0;
> @@ -718,7 +720,13 @@ static int axienet_free_tx_chain(struct axienet_local
> *lp, u32 first_bd,
> *sizep += status &
> XAXIDMA_BD_STS_ACTUAL_LEN_MASK;
> }
>
> - return i;
> + if (!force) {
Is tx_bd_ci increment dependent on force state and not done if force == true ?
> + lp->tx_bd_ci += i;
> + if (lp->tx_bd_ci >= lp->tx_bd_num)
> + lp->tx_bd_ci %= lp->tx_bd_num;
> + }
> +
> + return packets;
> }
>
> /**
> @@ -891,13 +899,10 @@ static int axienet_tx_poll(struct napi_struct *napi,
> int budget)
> u32 size = 0;
> int packets;
>
> - packets = axienet_free_tx_chain(lp, lp->tx_bd_ci, budget, false,
> &size, budget);
> + packets = axienet_free_tx_chain(lp, lp->tx_bd_ci, lp->tx_bd_num,
Why do we need to pass tx_bd_num here? Is budget not sufficient?
> false,
> + &size, budget);
>
> if (packets) {
> - lp->tx_bd_ci += packets;
> - if (lp->tx_bd_ci >= lp->tx_bd_num)
> - lp->tx_bd_ci %= lp->tx_bd_num;
> -
> u64_stats_update_begin(&lp->tx_stat_sync);
> u64_stats_add(&lp->tx_packets, packets);
> u64_stats_add(&lp->tx_bytes, size);
> @@ -1003,7 +1008,7 @@ axienet_start_xmit(struct sk_buff *skb, struct
> net_device *ndev)
> netdev_err(ndev, "TX DMA mapping
> error\n");
> ndev->stats.tx_dropped++;
> axienet_free_tx_chain(lp, orig_tail_ptr, ii + 1,
> - true, NULL, 0);
> + true, NULL, INT_MAX);
> return NETDEV_TX_OK;
> }
> desc_set_phys_addr(lp, phys, cur_p);
> --
> 2.35.1.1320.gc452695387.dirty
Powered by blists - more mailing lists