From: Mitch Williams Date: Mon, 18 Dec 2017 10:15:25 +0000 (-0500) Subject: i40e: avoid divide by zero X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b356dac8ab9e5e5954e550f2e2501b28511e90b8;p=linux.git 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 --- diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index e29d42c67fa91..db7dd812c1dfc 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)