6.4-stable review patch. If anyone has any objections, please let me know.
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From: Jesse Brandeburg jesse.brandeburg@intel.com
[ 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 przemyslaw.kitszel@intel.com Signed-off-by: Jesse Brandeburg jesse.brandeburg@intel.com Reviewed-by: Leon Romanovsky leonro@nvidia.com Tested-by: Pucha Himasekhar Reddy himasekharx.reddy.pucha@intel.com (A Contingent worker at Intel) Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 619cb07a40691..25e09ab708ca1 100644 --- a/drivers/net/ethernet/intel/ice/ice_base.c +++ b/drivers/net/ethernet/intel/ice/ice_base.c @@ -393,7 +393,8 @@ static int ice_setup_rx_ctx(struct ice_rx_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;