i40e: fix endless loop under rtnl
The loop in i40e_get_capabilities can never end. The problem is that although i40e_aq_discover_capabilities returns with an error if there's a firmware problem, the returned error is not checked. There is a check for pf->hw.aq.asq_last_status but that value is set to I40E_AQ_RC_OK on most firmware problems. When i40e_aq_discover_capabilities encounters a firmware problem, it will encounter the same problem on its next invocation. As the result, the loop becomes endless. We hit this with I40E_ERR_ADMIN_QUEUE_TIMEOUT but looking at the code, it can happen with a range of other firmware errors. I don't know what the correct behavior should be: whether the firmware should be retried a few times, or whether pf->hw.aq.asq_last_status should be always set to the encountered firmware error (but then it would be pointless and can be just replaced by the i40e_aq_discover_capabilities return value). However, the current behavior with an endless loop under the rtnl mutex(!) is unacceptable and Intel has not submitted a fix, although we explained the bug to them 7 months ago. This may not be the best possible fix but it's better than hanging the whole system on a firmware bug. Fixes: 56a62fc8 ("i40e: init code and hardware support") Tested-by:Stefan Assmann <sassmann@redhat.com> Signed-off-by:
Jiri Benc <jbenc@redhat.com> Reviewed-by:
Jesse Brandeburg <jesse.brandeburg@intel.com> Tested-by:
Dave Switzer <david.switzer@intel.com> Signed-off-by:
Tony Nguyen <anthony.l.nguyen@intel.com>
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