netdev - [[PATCH v2 iwl-next] v2 1/4] idpf: address an rtnl lock splat in tx timeout recovery path

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Message-ID: <20240826181032.3042222-2-manojvishy@google.com>
Date: Mon, 26 Aug 2024 18:10:29 +0000
From: Manoj Vishwanathan <manojvishy@...gle.com>
To: Tony Nguyen <anthony.l.nguyen@...el.com>, 
	Przemek Kitszel <przemyslaw.kitszel@...el.com>, "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, intel-wired-lan@...ts.osuosl.org
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	google-lan-reviews@...glegroups.com, David Decotigny <decot@...gle.com>, 
	Manoj Vishwanathan <manojvishy@...gle.com>
Subject: [[PATCH v2 iwl-next] v2 1/4] idpf: address an rtnl lock splat in tx
 timeout recovery path

From: David Decotigny <decot@...gle.com>

Adopt the same pattern as in other places in the code to take the rtnl
lock during hard resets.
Tested the patch by injecting tx timeout in IDPF , observe that idpf
recovers and IDPF comes back reachable

Without this patch causes there is a splat:
[  270.145214] WARNING: CPU:  PID:  at net/sched/sch_generic.c:534 dev_watchdog

Fixes: d4d5587182664 (idpf: initialize interrupts and enable vport)
Signed-off-by: Manoj Vishwanathan <manojvishy@...gle.com>
---
 drivers/net/ethernet/intel/idpf/idpf_txrx.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
index af2879f03b8d..806a8b6ea5c5 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
@@ -4326,6 +4326,7 @@ int idpf_vport_intr_alloc(struct idpf_vport *vport)
  */
 int idpf_vport_intr_init(struct idpf_vport *vport)
 {
+	bool hr_reset_in_prog;
 	char *int_name;
 	int err;
 
@@ -4334,8 +4335,19 @@ int idpf_vport_intr_init(struct idpf_vport *vport)
 		return err;
 
 	idpf_vport_intr_map_vector_to_qs(vport);
+	/** 
+	 * If we're in normal up path, the stack already takes the
+	 * rtnl_lock for us, however, if we're doing up as a part of a
+	 * hard reset, we'll need to take the lock ourself before
+	 * touching the netdev.
+	 */
+	hr_reset_in_prog = test_bit(IDPF_HR_RESET_IN_PROG,
+					vport->adapter->flags);
+	if (hr_reset_in_prog)
+		rtnl_lock();
 	idpf_vport_intr_napi_add_all(vport);
-
+	if (hr_reset_in_prog)
+		rtnl_unlock();
 	err = vport->adapter->dev_ops.reg_ops.intr_reg_init(vport);
 	if (err)
 		goto unroll_vectors_alloc;
-- 
2.46.0.295.g3b9ea8a38a-goog