[PATCH V3 net] net: mana: Fix error handling in mana_create_txq/rxq's NAPI cleanup

[Souradeep Chakrabarti <schakrabarti@xxxxxxxxxxxxxxxxxxx>]

Currently napi_disable() gets called during rxq and txq cleanup,
even before napi is enabled and hrtimer is initialized. It causes
kernel panic.

? page_fault_oops+0x136/0x2b0
  ? page_counter_cancel+0x2e/0x80
  ? do_user_addr_fault+0x2f2/0x640
  ? refill_obj_stock+0xc4/0x110
  ? exc_page_fault+0x71/0x160
  ? asm_exc_page_fault+0x27/0x30
  ? __mmdrop+0x10/0x180
  ? __mmdrop+0xec/0x180
  ? hrtimer_active+0xd/0x50
  hrtimer_try_to_cancel+0x2c/0xf0
  hrtimer_cancel+0x15/0x30
  napi_disable+0x65/0x90
  mana_destroy_rxq+0x4c/0x2f0
  mana_create_rxq.isra.0+0x56c/0x6d0
  ? mana_uncfg_vport+0x50/0x50
  mana_alloc_queues+0x21b/0x320
  ? skb_dequeue+0x5f/0x80

Cc: stable@xxxxxxxxxxxxxxx
Fixes: e1b5683ff62e ("net: mana: Move NAPI from EQ to CQ")
Signed-off-by: Souradeep Chakrabarti <schakrabarti@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Reviewed-by: Shradha Gupta <shradhagupta@xxxxxxxxxxxxxxxxxxx>
---
V3 -> V2:
Instead of using napi internal attribute, using an atomic
attribute to verify napi is initialized for a particular txq / rxq.

V2 -> V1:
Addressed the comment on cleaning up napi for the queues,
where queue creation was successful.
---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 30 ++++++++++++-------
 include/net/mana/mana.h                       |  4 +++
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 39f56973746d..bd303c89cfa6 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -1872,10 +1872,12 @@ static void mana_destroy_txq(struct mana_port_context *apc)
 
 	for (i = 0; i < apc->num_queues; i++) {
 		napi = &apc->tx_qp[i].tx_cq.napi;
-		napi_synchronize(napi);
-		napi_disable(napi);
-		netif_napi_del(napi);
-
+		if (atomic_read(&apc->tx_qp[i].txq.napi_initialized)) {
+			napi_synchronize(napi);
+			napi_disable(napi);
+			netif_napi_del(napi);
+			atomic_set(&apc->tx_qp[i].txq.napi_initialized, 0);
+		}
 		mana_destroy_wq_obj(apc, GDMA_SQ, apc->tx_qp[i].tx_object);
 
 		mana_deinit_cq(apc, &apc->tx_qp[i].tx_cq);
@@ -1931,6 +1933,7 @@ static int mana_create_txq(struct mana_port_context *apc,
 		txq->ndev = net;
 		txq->net_txq = netdev_get_tx_queue(net, i);
 		txq->vp_offset = apc->tx_vp_offset;
+		atomic_set(&txq->napi_initialized, 0);
 		skb_queue_head_init(&txq->pending_skbs);
 
 		memset(&spec, 0, sizeof(spec));
@@ -1997,6 +2000,7 @@ static int mana_create_txq(struct mana_port_context *apc,
 
 		netif_napi_add_tx(net, &cq->napi, mana_poll);
 		napi_enable(&cq->napi);
+		atomic_set(&txq->napi_initialized, 1);
 
 		mana_gd_ring_cq(cq->gdma_cq, SET_ARM_BIT);
 	}
@@ -2023,14 +2027,18 @@ static void mana_destroy_rxq(struct mana_port_context *apc,
 
 	napi = &rxq->rx_cq.napi;
 
-	if (validate_state)
-		napi_synchronize(napi);
+	if (atomic_read(&rxq->napi_initialized)) {
 
-	napi_disable(napi);
+		if (validate_state)
+			napi_synchronize(napi);
 
-	xdp_rxq_info_unreg(&rxq->xdp_rxq);
+		napi_disable(napi);
 
-	netif_napi_del(napi);
+		netif_napi_del(napi);
+		atomic_set(&rxq->napi_initialized, 0);
+	}
+
+	xdp_rxq_info_unreg(&rxq->xdp_rxq);
 
 	mana_destroy_wq_obj(apc, GDMA_RQ, rxq->rxobj);
 
@@ -2199,6 +2207,7 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 	rxq->num_rx_buf = RX_BUFFERS_PER_QUEUE;
 	rxq->rxq_idx = rxq_idx;
 	rxq->rxobj = INVALID_MANA_HANDLE;
+	atomic_set(&rxq->napi_initialized, 0);
 
 	mana_get_rxbuf_cfg(ndev->mtu, &rxq->datasize, &rxq->alloc_size,
 			   &rxq->headroom);
@@ -2286,6 +2295,8 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 
 	napi_enable(&cq->napi);
 
+	atomic_set(&rxq->napi_initialized, 1);
+
 	mana_gd_ring_cq(cq->gdma_cq, SET_ARM_BIT);
 out:
 	if (!err)
@@ -2336,7 +2347,6 @@ static void mana_destroy_vport(struct mana_port_context *apc)
 		rxq = apc->rxqs[rxq_idx];
 		if (!rxq)
 			continue;
-
 		mana_destroy_rxq(apc, rxq, true);
 		apc->rxqs[rxq_idx] = NULL;
 	}
diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
index 7caa334f4888..be75abd63dc8 100644
--- a/include/net/mana/mana.h
+++ b/include/net/mana/mana.h
@@ -98,6 +98,8 @@ struct mana_txq {
 
 	atomic_t pending_sends;
 
+	atomic_t napi_initialized;
+
 	struct mana_stats_tx stats;
 };
 
@@ -335,6 +337,8 @@ struct mana_rxq {
 	bool xdp_flush;
 	int xdp_rc; /* XDP redirect return code */
 
+	atomic_t napi_initialized;
+
 	struct page_pool *page_pool;
 
 	/* MUST BE THE LAST MEMBER:
-- 
2.34.1