net: mana: Fix potential deadlocks in mana napi ops

When net_shaper_ops are enabled for MANA, netdev_ops_lock
becomes active.

MANA VF setup/teardown by netvsc follows this call chain:

netvsc_vf_setup()
        dev_change_flags()
		...
         __dev_open() OR __dev_close()

dev_change_flags() holds the netdev mutex via netdev_lock_ops.

Meanwhile, mana_create_txq() and mana_create_rxq() in mana_open()
path call NAPI APIs (netif_napi_add_tx(), netif_napi_add_weight(),
napi_enable()), which also try to acquire the same lock, risking
deadlock.

Similarly in the teardown path (mana_close()), netif_napi_disable()
and netif_napi_del(), contend for the same lock.

Switch to the _locked variants of these APIs to avoid deadlocks
when the netdev_ops_lock is held.

Fixes: d4c22ec680c8 ("net: hold netdev instance lock during ndo_open/ndo_stop")
Signed-off-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Saurabh Singh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Link: https://patch.msgid.link/1750144656-2021-2-git-send-email-ernis@linux.microsoft.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index e68b8190bb7a83827a3c86bdc36344f400be2034..bcc33ea7aca3a90299a7bc192931e993abaf5356 100644 (file)
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -1912,8 +1912,10 @@ static void mana_destroy_txq(struct mana_port_context *apc)
                napi = &apc->tx_qp[i].tx_cq.napi;
                if (apc->tx_qp[i].txq.napi_initialized) {
                        napi_synchronize(napi);
-                       napi_disable(napi);
-                       netif_napi_del(napi);
+                       netdev_lock_ops_to_full(napi->dev);
+                       napi_disable_locked(napi);
+                       netif_napi_del_locked(napi);
+                       netdev_unlock_full_to_ops(napi->dev);
                        apc->tx_qp[i].txq.napi_initialized = false;
                }
                mana_destroy_wq_obj(apc, GDMA_SQ, apc->tx_qp[i].tx_object);
@@ -2065,8 +2067,11 @@ static int mana_create_txq(struct mana_port_context *apc,
 
                mana_create_txq_debugfs(apc, i);
 
-               netif_napi_add_tx(net, &cq->napi, mana_poll);
-               napi_enable(&cq->napi);
+               set_bit(NAPI_STATE_NO_BUSY_POLL, &cq->napi.state);
+               netdev_lock_ops_to_full(net);
+               netif_napi_add_locked(net, &cq->napi, mana_poll);
+               napi_enable_locked(&cq->napi);
+               netdev_unlock_full_to_ops(net);
                txq->napi_initialized = true;
 
                mana_gd_ring_cq(cq->gdma_cq, SET_ARM_BIT);
@@ -2102,9 +2107,10 @@ static void mana_destroy_rxq(struct mana_port_context *apc,
        if (napi_initialized) {
                napi_synchronize(napi);
 
-               napi_disable(napi);
-
-               netif_napi_del(napi);
+               netdev_lock_ops_to_full(napi->dev);
+               napi_disable_locked(napi);
+               netif_napi_del_locked(napi);
+               netdev_unlock_full_to_ops(napi->dev);
        }
        xdp_rxq_info_unreg(&rxq->xdp_rxq);
 
@@ -2355,14 +2361,18 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 
        gc->cq_table[cq->gdma_id] = cq->gdma_cq;
 
-       netif_napi_add_weight(ndev, &cq->napi, mana_poll, 1);
+       netdev_lock_ops_to_full(ndev);
+       netif_napi_add_weight_locked(ndev, &cq->napi, mana_poll, 1);
+       netdev_unlock_full_to_ops(ndev);
 
        WARN_ON(xdp_rxq_info_reg(&rxq->xdp_rxq, ndev, rxq_idx,
                                 cq->napi.napi_id));
        WARN_ON(xdp_rxq_info_reg_mem_model(&rxq->xdp_rxq, MEM_TYPE_PAGE_POOL,
                                           rxq->page_pool));
 
-       napi_enable(&cq->napi);
+       netdev_lock_ops_to_full(ndev);
+       napi_enable_locked(&cq->napi);
+       netdev_unlock_full_to_ops(ndev);
 
        mana_gd_ring_cq(cq->gdma_cq, SET_ARM_BIT);
 out: