iwlwifi: mvm: don't capture firmware coredump for D3->D0 reconfig

The code to capture firmware errors works during the reconfiguration
phase after an error. As the D3->D0 transition uses the same flow to
get the D0 image reconfigured, this triggered and caused a firmware
coredump to be collected. This in turn, if it isn't picked up by
userspace, can cause module unloading to fail, which is how the bug
was detected.

To fix this issue, introduce a new status flag (D3_RECONFIG) and use
it to detect that during reconfiguration no coredump should be taken
and reported.
Reported-by: NAvi Kraif <avix.kraif@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/d3.c

@@ -1651,6 +1651,7 @@ static int __iwl_mvm_resume(struct iwl_mvm *mvm, bool test)
 
 	/* return 1 to reconfigure the device */
 	set_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status);
+	set_bit(IWL_MVM_STATUS_D3_RECONFIG, &mvm->status);
 	return 1;
 }
 

drivers/net/wireless/iwlwifi/mvm/mac80211.c

@@ -839,7 +839,12 @@ void iwl_mvm_fw_error_dump(struct iwl_mvm *mvm)
 
 static void iwl_mvm_restart_cleanup(struct iwl_mvm *mvm)
 {
-	iwl_mvm_fw_error_dump(mvm);
+	/* clear the D3 reconfig, we only need it to avoid dumping a
+	 * firmware coredump on reconfiguration, we shouldn't do that
+	 * on D3->D0 transition
+	 */
+	if (!test_and_clear_bit(IWL_MVM_STATUS_D3_RECONFIG, &mvm->status))
+		iwl_mvm_fw_error_dump(mvm);
 
 	iwl_trans_stop_device(mvm->trans);
 

drivers/net/wireless/iwlwifi/mvm/mvm.h

@@ -750,6 +750,7 @@ enum iwl_mvm_status {
 	IWL_MVM_STATUS_IN_HW_RESTART,
 	IWL_MVM_STATUS_IN_D0I3,
 	IWL_MVM_STATUS_ROC_AUX_RUNNING,
+	IWL_MVM_STATUS_D3_RECONFIG,
 };
 
 static inline bool iwl_mvm_is_radio_killed(struct iwl_mvm *mvm)