From b356dac8ab9e5e5954e550f2e2501b28511e90b8 Mon Sep 17 00:00:00 2001 From: Mitch Williams Date: Mon, 18 Dec 2017 05:15:25 -0500 Subject: [PATCH] i40e: avoid divide by zero In some weird circumstances with DCB enabled, the firmware can fail to configure the VSI, leaving us with zero traffic classes. Check for this state when we configure RSS to avoid a panic. Signed-off-by: Mitch Williams Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e_main.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index e29d42c67fa9..db7dd812c1df 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -10783,8 +10783,13 @@ static int i40e_pf_config_rss(struct i40e_pf *pf) /* Determine the RSS size of the VSI */ if (!vsi->rss_size) { u16 qcount; - - qcount = vsi->num_queue_pairs / vsi->tc_config.numtc; + /* If the firmware does something weird during VSI init, we + * could end up with zero TCs. Check for that to avoid + * divide-by-zero. It probably won't pass traffic, but it also + * won't panic. + */ + qcount = vsi->num_queue_pairs / + (vsi->tc_config.numtc ? vsi->tc_config.numtc : 1); vsi->rss_size = min_t(int, pf->alloc_rss_size, qcount); } if (!vsi->rss_size) -- 2.11.0