2021-03-26 10:31:53

by Luca Coelho

Subject: [PATCH for v5.12 4/7] iwlwifi: fw: fix notification wait locking

From: Johannes Berg <[email protected]>

Since we now call iwl_notification_wait_notify() from the
NAPI poll in soft-IRQ, we get a (valid) lockdep complaint
that we could get a deadlock by taking the spinlock from
sleeping context and then getting the soft-IRQ that also
tries to take it (in NAPI polling).

Fix this by disabling soft-IRQs for this lock.

Change-Id: Ic56f351d04674df70567bab0269cba91bdbc853c
Signed-off-by: Johannes Berg <[email protected]>
Fixes: 25edc8f259c7 ("iwlwifi: pcie: properly implement NAPI")
Signed-off-by: Luca Coelho <[email protected]>
---
drivers/net/wireless/intel/iwlwifi/fw/notif-wait.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/notif-wait.c b/drivers/net/wireless/intel/iwlwifi/fw/notif-wait.c
index 3dbc6f3f92cc..231d2517f398 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/notif-wait.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/notif-wait.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
- * Copyright (C) 2005-2014 Intel Corporation
+ * Copyright (C) 2005-2014, 2021 Intel Corporation
* Copyright (C) 2015-2017 Intel Deutschland GmbH
*/
#include <linux/sched.h>
@@ -26,7 +26,7 @@ bool iwl_notification_wait(struct iwl_notif_wait_data *notif_wait,
if (!list_empty(&notif_wait->notif_waits)) {
struct iwl_notification_wait *w;

- spin_lock(&notif_wait->notif_wait_lock);
+ spin_lock_bh(&notif_wait->notif_wait_lock);
list_for_each_entry(w, &notif_wait->notif_waits, list) {
int i;
bool found = false;
@@ -59,7 +59,7 @@ bool iwl_notification_wait(struct iwl_notif_wait_data *notif_wait,
triggered = true;
}
}
- spin_unlock(&notif_wait->notif_wait_lock);
+ spin_unlock_bh(&notif_wait->notif_wait_lock);
}

return triggered;
@@ -70,10 +70,10 @@ void iwl_abort_notification_waits(struct iwl_notif_wait_data *notif_wait)
{
struct iwl_notification_wait *wait_entry;

- spin_lock(&notif_wait->notif_wait_lock);
+ spin_lock_bh(&notif_wait->notif_wait_lock);
list_for_each_entry(wait_entry, &notif_wait->notif_waits, list)
wait_entry->aborted = true;
- spin_unlock(&notif_wait->notif_wait_lock);
+ spin_unlock_bh(&notif_wait->notif_wait_lock);

wake_up_all(&notif_wait->notif_waitq);
}
--
2.31.0