From: Arthur Kiyanovski <akiyano@amazon.com>
To: David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, <netdev@vger.kernel.org>
Cc: Arthur Kiyanovski <akiyano@amazon.com>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
David Woodhouse <dwmw@amazon.com>,
Zorik Machulsky <zorik@amazon.com>,
Alexander Matushevsky <matua@amazon.com>,
Saeed Bshara <saeedb@amazon.com>, Matt Wilson <msw@amazon.com>,
Anthony Liguori <aliguori@amazon.com>,
Nafea Bshara <nafea@amazon.com>,
Evgeny Schmeilin <evgenys@amazon.com>,
Netanel Belgazal <netanel@amazon.com>,
Ali Saidi <alisaidi@amazon.com>,
Benjamin Herrenschmidt <benh@amazon.com>,
Noam Dagan <ndagan@amazon.com>,
David Arinzon <darinzon@amazon.com>,
Evgeny Ostrovsky <evostrov@amazon.com>,
Ofir Tabachnik <ofirt@amazon.com>,
Amit Bernstein <amitbern@amazon.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
Saeed Bishara <saeed.bishara.os@gmail.com>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH v2,net] net: ena: PHC: Add missing barrier
Date: Thu, 4 Jun 2026 08:07:04 +0000 [thread overview]
Message-ID: <20260604080706.19366-1-akiyano@amazon.com> (raw)
Add dma_rmb() barrier after req_id completion check in
ena_com_phc_get_timestamp(). On weakly-ordered architectures,
payload fields may be read before req_id is observed as updated.
Fixes: e0ea34158ee8 ("net: ena: Add PHC support in the ENA driver")
Closes: https://sashiko.dev/#/patchset/20260430032507.11586-1-akiyano%40amazon.com
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
---
drivers/net/ethernet/amazon/ena/ena_com.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c
index 8c86789d867a..297fb36ab8c1 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -1880,6 +1880,11 @@ int ena_com_phc_get_timestamp(struct ena_com_dev *ena_dev, u64 *timestamp)
continue;
}
+ /* Ensure PHC payload (timestamp, error_flags) is read
+ * after req_id update is observed
+ */
+ dma_rmb();
+
/* req_id was updated by the device which indicates that
* PHC timestamp and error_flags are updated too,
* checking errors before retrieving timestamp
--
2.47.3
next reply other threads:[~2026-06-04 8:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 8:07 Arthur Kiyanovski [this message]
2026-06-06 1:50 ` [PATCH v2,net] net: ena: PHC: Add missing barrier patchwork-bot+netdevbpf
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