From 2572a0b29ad51c47428acf8219daec74b244a582 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Fri, 11 Dec 2020 15:57:11 +0100 Subject: [PATCH] ice, xsk: clear the status bits for the next_to_use descriptor MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit BugLink: https://bugs.launchpad.net/bugs/1910111 [ Upstream commit 8d14768a7972b92c73259f0c9c45b969d85e3a60 ] On the Rx side, the next_to_use index points to the next item in the HW ring to be refilled/allocated, and next_to_clean points to the next item to potentially be processed. When the HW Rx ring is fully refilled, i.e. no packets has been processed, the next_to_use will be next_to_clean - 1. When the ring is fully processed next_to_clean will be equal to next_to_use. The latter case is where a bug is triggered. If the next_to_use bits are not cleared, and the "fully processed" state is entered, a stale descriptor can be processed. The skb-path correctly clear the status bit for the next_to_use descriptor, but the AF_XDP zero-copy path did not do that. This change adds the status bits clearing of the next_to_use descriptor. Fixes: 2d4238f55697 ("ice: Add support for AF_XDP") Signed-off-by: Björn Töpel Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin Signed-off-by: Paolo Pisati --- drivers/net/ethernet/intel/ice/ice_xsk.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c index 797886524054..98101a8e2952 100644 --- a/drivers/net/ethernet/intel/ice/ice_xsk.c +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c @@ -446,8 +446,11 @@ bool ice_alloc_rx_bufs_zc(struct ice_ring *rx_ring, u16 count) } } while (--count); - if (rx_ring->next_to_use != ntu) + if (rx_ring->next_to_use != ntu) { + /* clear the status bits for the next_to_use descriptor */ + rx_desc->wb.status_error0 = 0; ice_release_rx_desc(rx_ring, ntu); + } return ret; } -- 2.39.5