netdev - [net 07/10] net/mlx5e: XDP, Fix XDP_REDIRECT mpwqe page fragment leaks on shutdown

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Message-ID: <20231012195127.129585-8-saeed@kernel.org>
Date: Thu, 12 Oct 2023 12:51:24 -0700
From: Saeed Mahameed <saeed@...nel.org>
To: "David S. Miller" <davem@...emloft.net>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Eric Dumazet <edumazet@...gle.com>
Cc: Saeed Mahameed <saeedm@...dia.com>,
	netdev@...r.kernel.org,
	Tariq Toukan <tariqt@...dia.com>,
	Dragos Tatulea <dtatulea@...dia.com>
Subject: [net 07/10] net/mlx5e: XDP, Fix XDP_REDIRECT mpwqe page fragment leaks on shutdown

From: Dragos Tatulea <dtatulea@...dia.com>

When mlx5e_xdp_xmit is called without the XDP_XMIT_FLUSH set it is
possible that it leaves a mpwqe session open. That is ok during runtime:
the session will be closed on the next call to mlx5e_xdp_xmit. But
having a mpwqe session still open at XDP sq close time is problematic:
the pc counter is not updated before flushing the contents of the
xdpi_fifo. This results in leaking page fragments.

The fix is to always close the mpwqe session at the end of
mlx5e_xdp_xmit, regardless of the XDP_XMIT_FLUSH flag being set or not.

Fixes: 5e0d2eef771e ("net/mlx5e: XDP, Support Enhanced Multi-Packet TX WQE")
Signed-off-by: Dragos Tatulea <dtatulea@...dia.com>
Reviewed-by: Tariq Toukan <tariqt@...dia.com>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
index 12f56d0db0af..8bed17d8fe56 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
@@ -874,11 +874,11 @@ int mlx5e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
 	}
 
 out:
-	if (flags & XDP_XMIT_FLUSH) {
-		if (sq->mpwqe.wqe)
-			mlx5e_xdp_mpwqe_complete(sq);
+	if (sq->mpwqe.wqe)
+		mlx5e_xdp_mpwqe_complete(sq);
+
+	if (flags & XDP_XMIT_FLUSH)
 		mlx5e_xmit_xdp_doorbell(sq);
-	}
 
 	return nxmit;
 }
-- 
2.41.0