i40e: Fix interface init with MSI interrupts (no MSI-X)

[ Upstream commit 5fcbb711024aac6d4db385623e6f2fdf019f7782 ] Fix the inability to bring an interface up on a setup with only MSI interrupts enabled (no MSI-X). Solution is to add a default number of QPs = 1. This is enough, since without MSI-X support driver enables only a basic feature set. Fixes: bc6d33c ("i40e: Fix the number of queues available to be mapped for use") Signed-off-by: Dawid Lukwinski <dawid.lukwinski@intel.com> Signed-off-by: Michal Maloszewski <michal.maloszewski@intel.com> Tested-by: Dave Switzer <david.switzer@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com> Link: https://lore.kernel.org/r/20220722175401.112572-1-anthony.l.nguyen@intel.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: mmalosze

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -1908,11 +1908,15 @@ static void i40e_vsi_setup_queue_map(struct i40e_vsi *vsi,
  * non-zero req_queue_pairs says that user requested a new
  * queue count via ethtool's set_channels, so use this
  * value for queues distribution across traffic classes
+ * We need at least one queue pair for the interface
+ * to be usable as we see in else statement.
  */
 if (vsi->req_queue_pairs > 0)
 vsi->num_queue_pairs = vsi->req_queue_pairs;
 else if (pf->flags & I40E_FLAG_MSIX_ENABLED)
 vsi->num_queue_pairs = pf->num_lan_msix;
+else
+vsi->num_queue_pairs = 1;
 }
 
 /* Number of queues per enabled TC */