netdev - [PATCH iwl-net v2 5/6] ice: remove ICE_CFG_BUSY locking from AF

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Message-ID: <20240724164840.2536605-6-larysa.zaremba@intel.com>
Date: Wed, 24 Jul 2024 18:48:36 +0200
From: Larysa Zaremba <larysa.zaremba@...el.com>
To: intel-wired-lan@...ts.osuosl.org
Cc: Larysa Zaremba <larysa.zaremba@...el.com>,
	Tony Nguyen <anthony.l.nguyen@...el.com>,
	"David S. Miller" <davem@...emloft.net>,
	Jacob Keller <jacob.e.keller@...el.com>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Jesper Dangaard Brouer <hawk@...nel.org>,
	John Fastabend <john.fastabend@...il.com>,
	Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	bpf@...r.kernel.org,
	magnus.karlsson@...el.com,
	Michal Kubiak <michal.kubiak@...el.com>,
	Wojciech Drewek <wojciech.drewek@...el.com>,
	Amritha Nambiar <amritha.nambiar@...el.com>
Subject: [PATCH iwl-net v2 5/6] ice: remove ICE_CFG_BUSY locking from AF_XDP code

Locking used in ice_qp_ena() and ice_qp_dis() does pretty much nothing,
because ICE_CFG_BUSY is a state flag that is supposed to be set in a PF
state, not VSI one. Therefore it does not protect the queue pair from
e.g. reset.

Despite being useless, it still can deadlock the unfortunate functions that
have fell into the same ICE_CFG_BUSY-VSI trap. This happens if ice_qp_ena
returns an error.

Remove ICE_CFG_BUSY locking from ice_qp_dis() and ice_qp_ena().

Fixes: 2d4238f55697 ("ice: Add support for AF_XDP")
Reviewed-by: Wojciech Drewek <wojciech.drewek@...el.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@...el.com>
---
 drivers/net/ethernet/intel/ice/ice_xsk.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index 5dd50a2866cc..d23fd4ea9129 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -163,7 +163,6 @@ static int ice_qp_dis(struct ice_vsi *vsi, u16 q_idx)
 	struct ice_q_vector *q_vector;
 	struct ice_tx_ring *tx_ring;
 	struct ice_rx_ring *rx_ring;
-	int timeout = 50;
 	int err;
 
 	if (q_idx >= vsi->num_rxq || q_idx >= vsi->num_txq)
@@ -173,13 +172,6 @@ static int ice_qp_dis(struct ice_vsi *vsi, u16 q_idx)
 	rx_ring = vsi->rx_rings[q_idx];
 	q_vector = rx_ring->q_vector;
 
-	while (test_and_set_bit(ICE_CFG_BUSY, vsi->state)) {
-		timeout--;
-		if (!timeout)
-			return -EBUSY;
-		usleep_range(1000, 2000);
-	}
-
 	ice_qvec_dis_irq(vsi, rx_ring, q_vector);
 	ice_qvec_toggle_napi(vsi, q_vector, false);
 
@@ -250,7 +242,6 @@ static int ice_qp_ena(struct ice_vsi *vsi, u16 q_idx)
 	ice_qvec_ena_irq(vsi, q_vector);
 
 	netif_tx_start_queue(netdev_get_tx_queue(vsi->netdev, q_idx));
-	clear_bit(ICE_CFG_BUSY, vsi->state);
 
 	return 0;
 }
-- 
2.43.0