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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,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Shwetha Nagaraju <shwetha.nagaraju@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 190/285] ice: clear cmd_type_offset_bsz for TX rings
Date:   Tue, 12 Apr 2022 08:30:47 +0200
Message-Id: <20220412062949.146312296@linuxfoundation.org>
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From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

[ Upstream commit e19778e6c911691856447c3bf9617f00b3e1347f ]

Currently when XDP rings are created, each descriptor gets its DD bit
set, which turns out to be the wrong approach as it can lead to a
situation where more descriptors get cleaned than it was supposed to,
e.g. when AF_XDP busy poll is run with a large batch size. In this
situation, the driver would request for more buffers than it is able to
handle.

Fix this by not setting the DD bits in ice_xdp_alloc_setup_rings(). They
should be initialized to zero instead.

Fixes: 9610bd988df9 ("ice: optimize XDP_TX workloads")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Shwetha Nagaraju <shwetha.nagaraju@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ice/ice_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index cd2fb24c3005..65742f296b0d 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -2528,7 +2528,7 @@ static int ice_xdp_alloc_setup_rings(struct ice_vsi *vsi)
 		spin_lock_init(&xdp_ring->tx_lock);
 		for (j = 0; j < xdp_ring->count; j++) {
 			tx_desc = ICE_TX_DESC(xdp_ring, j);
-			tx_desc->cmd_type_offset_bsz = cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE);
+			tx_desc->cmd_type_offset_bsz = 0;
 		}
 	}
 
-- 
2.35.1