[Intel-wired-lan] [next PATCH S83-V5 2/9] i40e: avoid divide by zero
Alice Michael
alice.michael at intel.com
Mon Dec 18 10:15:25 UTC 2017
From: Mitch Williams <mitch.a.williams at intel.com>
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 <mitch.a.williams at intel.com>
---
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 4f74156..7a882d7 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -10839,8 +10839,13 @@ 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)
--
2.9.5
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