From fa7d7a7f007b06ba4f9722e3226c50bded53649f Mon Sep 17 00:00:00 2001 From: Jesse Brandeburg Date: Thu, 10 Aug 2023 16:51:10 -0700 Subject: [PATCH] ice: fix receive buffer size miscalculation [ Upstream commit 10083aef784031fa9f06c19a1b182e6fad5338d9 ] The driver is misconfiguring the hardware for some values of MTU such that it could use multiple descriptors to receive a packet when it could have simply used one. Change the driver to use a round-up instead of the result of a shift, as the shift can truncate the lower bits of the size, and result in the problem noted above. It also aligns this driver with similar code in i40e. The insidiousness of this problem is that everything works with the wrong size, it's just not working as well as it could, as some MTU sizes end up using two or more descriptors, and there is no way to tell that is happening without looking at ice_trace or a bus analyzer. Fixes: efc2214b6047 ("ice: Add support for XDP") Reviewed-by: Przemek Kitszel Signed-off-by: Jesse Brandeburg Reviewed-by: Leon Romanovsky Tested-by: Pucha Himasekhar Reddy (A Contingent worker at Intel) Signed-off-by: Tony Nguyen Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/ice/ice_base.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c index 1929847b8c40..59df4c9bd8f9 100644 --- a/drivers/net/ethernet/intel/ice/ice_base.c +++ b/drivers/net/ethernet/intel/ice/ice_base.c @@ -353,7 +353,8 @@ int ice_setup_rx_ctx(struct ice_ring *ring) /* Receive Packet Data Buffer Size. * The Packet Data Buffer Size is defined in 128 byte units. */ - rlan_ctx.dbuf = ring->rx_buf_len >> ICE_RLAN_CTX_DBUF_S; + rlan_ctx.dbuf = DIV_ROUND_UP(ring->rx_buf_len, + BIT_ULL(ICE_RLAN_CTX_DBUF_S)); /* use 32 byte descriptors */ rlan_ctx.dsize = 1;