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From: Larysa Zaremba <larysa.zaremba@intel.com>
To: intel-wired-lan@lists.osuosl.org
Cc: Larysa Zaremba <larysa.zaremba@intel.com>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
	netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	bpf@vger.kernel.org,
	magnus.karlsson@intel.com,
	Michal Kubiak <michal.kubiak@intel.com>,
	Igor Bagnucki <igor.bagnucki@intel.com>
Subject: [PATCH iwl-net 3/3] ice: make NAPI setting code aware that rtnl-locked request is waiting
Date: Mon, 10 Jun 2024 17:37:15 +0200
Message-ID: <20240610153716.31493-4-larysa.zaremba@intel.com>
In-Reply-To: <20240610153716.31493-1-larysa.zaremba@intel.com>
References: <20240610153716.31493-1-larysa.zaremba@intel.com>
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ice_vsi_rebuild() is a critical section in the reset path. Sometimes,
rtnl-locked callbacks have to wait for it to finish. However, it is
possible they will wait for an eternity, because the critical section
contains calls to ice_queue_set_napi() that try to take rtnl_lock.

Make ice_queue_set_napi() aware that some rtnl-locked code is waiting and
skip taking the lock, if this is the case.

Fixes: 080b0c8d6d26 ("ice: Fix ASSERT_RTNL() warning during certain scenarios")
Reviewed-by: Igor Bagnucki <igor.bagnucki@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
---
 drivers/net/ethernet/intel/ice/ice.h      |  1 +
 drivers/net/ethernet/intel/ice/ice_lib.c  | 18 +++++++++++++++---
 drivers/net/ethernet/intel/ice/ice_main.c |  5 ++++-
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
index 76590cfcaf68..7c1e24afa34b 100644
--- a/drivers/net/ethernet/intel/ice/ice.h
+++ b/drivers/net/ethernet/intel/ice/ice.h
@@ -307,6 +307,7 @@ enum ice_pf_state {
 	ICE_PHY_INIT_COMPLETE,
 	ICE_FD_VF_FLUSH_CTX,		/* set at FD Rx IRQ or timeout */
 	ICE_AUX_ERR_PENDING,
+	ICE_RTNL_WAITS_FOR_RESET,
 	ICE_STATE_NBITS		/* must be last */
 };
 
diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 4774bcc4d5a8..a5dc6fc6e63d 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -2740,12 +2740,24 @@ ice_queue_set_napi(struct ice_vsi *vsi, unsigned int queue_index,
 	if (current_work() == &pf->serv_task ||
 	    test_bit(ICE_PREPARED_FOR_RESET, pf->state) ||
 	    test_bit(ICE_DOWN, pf->state) ||
-	    test_bit(ICE_SUSPENDED, pf->state))
+	    test_bit(ICE_SUSPENDED, pf->state)) {
+		bool rtnl_held_here = true;
+
+		while (!rtnl_trylock()) {
+			if (test_bit(ICE_RTNL_WAITS_FOR_RESET, pf->state)) {
+				rtnl_held_here = false;
+				break;
+			}
+			usleep_range(1000, 2000);
+		}
 		__ice_queue_set_napi(vsi->netdev, queue_index, type, napi,
-				     false);
-	else
+				     true);
+		if (rtnl_held_here)
+			rtnl_unlock();
+	} else {
 		__ice_queue_set_napi(vsi->netdev, queue_index, type, napi,
 				     true);
+	}
 }
 
 /**
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index cd8be3c3b956..37b3dd22cdc2 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -3103,8 +3103,11 @@ static int ice_xdp(struct net_device *dev, struct netdev_bpf *xdp)
 		return -EINVAL;
 	}
 
-	while (test_and_set_bit(ICE_CFG_BUSY, pf->state))
+	while (test_and_set_bit(ICE_CFG_BUSY, pf->state)) {
+		set_bit(ICE_RTNL_WAITS_FOR_RESET, pf->state);
 		usleep_range(1000, 2000);
+	}
+	clear_bit(ICE_RTNL_WAITS_FOR_RESET, pf->state);
 
 	switch (xdp->command) {
 	case XDP_SETUP_PROG:
-- 
2.43.0