-----Original Message-----
From: Andrew Lunn <andrew@lunn.ch>
Sent: Thursday, September 29, 2022 8:24 AM
To: Shenwei Wang <shenwei.wang@nxp.com>
Cc: Joakim Zhang <redacted>; David S. Miller
[off-list ref]; Eric Dumazet [off-list ref]; Jakub
Kicinski [off-list ref]; Paolo Abeni [off-list ref]; Alexei
Starovoitov [off-list ref]; Daniel Borkmann [off-list ref];
Jesper Dangaard Brouer [off-list ref]; John Fastabend
[off-list ref]; netdev@vger.kernel.org; linux-
kernel@vger.kernel.org; imx@lists.linux.dev
Subject: Re: [EXT] Re: [PATCH 1/1] net: fec: add initial XDP support

Caution: EXT Email

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+struct fec_enet_xdp_stats {
+     u64     xdp_pass;
+     u64     xdp_drop;
+     u64     xdp_xmit;
+     u64     xdp_redirect;
+     u64     xdp_xmit_err;
+     u64     xdp_tx;
+     u64     xdp_tx_err;
+};
+
+     switch (act) {
+     case XDP_PASS:
+             rxq->stats.xdp_pass++;

Since the stats are u64, and most machines using the FEC are 32 bit,
you cannot just do an increment. Took a look at u64_stats_sync.h.

quoted

As this increment is only executed under the NAPI kthread context, is
the protection still required?

Are the statistics values read by ethtool under NAPI kthread context?

You are right. The read is not under NAPI context.

Thanks,
Shenwei

    Andrew