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From:   gregory.greenman@intel.com
To:     johannes@sipsolutions.net
Cc:     linux-wireless@vger.kernel.org,
        Johannes Berg <johannes.berg@intel.com>,
        Gregory Greenman <gregory.greenman@intel.com>
Subject: [PATCH 01/15] wifi: iwlwifi: pcie: rescan bus if no parent
Date:   Wed, 13 Sep 2023 14:56:37 +0300
Message-Id: <20230913145231.f7795a1ccdab.I2b84810a743469a1bcabf3628262cf54311593f4@changeid>
In-Reply-To: <20230913115651.190558-1-gregory.greenman@intel.com>
References: <20230913115651.190558-1-gregory.greenman@intel.com>
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From: Johannes Berg <johannes.berg@intel.com>

If the bus has no parent due to the topology, platform level device
reset (PLDR) wouldn't work. On the other hand, some platforms appear
to require scanning the parent, though it's not clear why.

However if there's no parent, then we skip the rescan, which isn't a
good idea. Change the code to go to the parent only if that exists,
and rescan the bus itself where it doesn't.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index a9e00a2cd9ba..51012435e39b 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -2112,8 +2112,11 @@ static void iwl_trans_pcie_removal_wk(struct work_struct *wk)
 	pci_lock_rescan_remove();
 	pci_dev_put(pdev);
 	pci_stop_and_remove_bus_device(pdev);
-	if (removal->rescan)
-		pci_rescan_bus(bus->parent);
+	if (removal->rescan && bus) {
+		if (bus->parent)
+			bus = bus->parent;
+		pci_rescan_bus(bus);
+	}
 	pci_unlock_rescan_remove();
 
 	kfree(removal);
-- 
2.38.1