net/mlx5e: XDP, Fix XDP_REDIRECT mpwqe page fragment leaks on shutdown

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: 5e0d2ee ("net/mlx5e: XDP, Support Enhanced Multi-Packet TX WQE")
Signed-off-by: Dragos Tatulea <[email protected]>
Reviewed-by: Tariq Toukan <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>

Author: dtatulea

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;
 }