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

From: Manoj Vishwanathan
Date: Mon Aug 26 2024 - 14:11:00 EST


From: David Decotigny <decot@xxxxxxxxxx>

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@xxxxxxxxxx>
---
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