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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Alexander Lobakin <alexandr.lobakin@intel.com>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Magnus Karlsson <magnus.karlsson@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 23/86] ice: xsk: Force rings to be sized to power of 2
Date:   Mon, 29 Aug 2022 12:58:49 +0200
Message-Id: <20220829105757.479967257@linuxfoundation.org>
In-Reply-To: <20220829105756.500128871@linuxfoundation.org>
References: <20220829105756.500128871@linuxfoundation.org>
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From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

[ Upstream commit 296f13ff3854535009a185aaf8e3603266d39d94 ]

With the upcoming introduction of batching to XSK data path,
performance wise it will be the best to have the ring descriptor count
to be aligned to power of 2.

Check if ring sizes that user is going to attach the XSK socket fulfill
the condition above. For Tx side, although check is being done against
the Tx queue and in the end the socket will be attached to the XDP
queue, it is fine since XDP queues get the ring->count setting from Tx
queues.

Suggested-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20220125160446.78976-3-maciej.fijalkowski@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ice/ice_xsk.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index 5733526fa245c..4bb62950d92de 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -371,6 +371,13 @@ int ice_xsk_pool_setup(struct ice_vsi *vsi, struct xsk_buff_pool *pool, u16 qid)
 	bool if_running, pool_present = !!pool;
 	int ret = 0, pool_failure = 0;
 
+	if (!is_power_of_2(vsi->rx_rings[qid]->count) ||
+	    !is_power_of_2(vsi->tx_rings[qid]->count)) {
+		netdev_err(vsi->netdev, "Please align ring sizes to power of 2\n");
+		pool_failure = -EINVAL;
+		goto failure;
+	}
+
 	if_running = netif_running(vsi->netdev) && ice_is_xdp_ena_vsi(vsi);
 
 	if (if_running) {
@@ -393,6 +400,7 @@ int ice_xsk_pool_setup(struct ice_vsi *vsi, struct xsk_buff_pool *pool, u16 qid)
 			netdev_err(vsi->netdev, "ice_qp_ena error = %d\n", ret);
 	}
 
+failure:
 	if (pool_failure) {
 		netdev_err(vsi->netdev, "Could not %sable buffer pool, error = %d\n",
 			   pool_present ? "en" : "dis", pool_failure);
-- 
2.35.1