wifi: iwlwifi: pcie: allocate dummy net_device dynamically

struct net_device shouldn't be embedded into any structure, instead,
the owner should use the priv space to embed their state into net_device.

Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_device from struct iwl_trans_pcie by converting it
into a pointer. Then use the leverage alloc_netdev() to allocate the
net_device object at iwl_trans_pcie_alloc.

The private data of net_device becomes a pointer for the struct
iwl_trans_pcie, so, it is easy to get back to the iwl_trans_pcie parent
given the net_device object.

[1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://msgid.link/20240501165417.3406039-1-leitao@debian.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
index 7805a42948afe9992687ab4244bc44d626f51317..a7eebe400b5b97ed182a2fcd9465b424d113e7d7 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
@@ -386,7 +386,7 @@ struct iwl_trans_pcie {
        dma_addr_t iml_dma_addr;
        struct iwl_trans *trans;
 
-       struct net_device napi_dev;
+       struct net_device *napi_dev;
 
        /* INT ICT Table */
        __le32 *ict_tbl;

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index 9c2461ba13c588e3ecd99a285b8b432a6e3f9787..984d7bcd381fa7448370269397a95e2570862592 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -1000,6 +1000,11 @@ void iwl_pcie_rx_init_rxb_lists(struct iwl_rxq *rxq)
 
 static int iwl_pcie_rx_handle(struct iwl_trans *trans, int queue, int budget);
 
+static inline struct iwl_trans_pcie *iwl_netdev_to_trans_pcie(struct net_device *dev)
+{
+       return *(struct iwl_trans_pcie **)netdev_priv(dev);
+}
+
 static int iwl_pcie_napi_poll(struct napi_struct *napi, int budget)
 {
        struct iwl_rxq *rxq = container_of(napi, struct iwl_rxq, napi);
@@ -1007,7 +1012,7 @@ static int iwl_pcie_napi_poll(struct napi_struct *napi, int budget)
        struct iwl_trans *trans;
        int ret;
 
-       trans_pcie = container_of(napi->dev, struct iwl_trans_pcie, napi_dev);
+       trans_pcie = iwl_netdev_to_trans_pcie(napi->dev);
        trans = trans_pcie->trans;
 
        ret = iwl_pcie_rx_handle(trans, rxq->id, budget);
@@ -1034,7 +1039,7 @@ static int iwl_pcie_napi_poll_msix(struct napi_struct *napi, int budget)
        struct iwl_trans *trans;
        int ret;
 
-       trans_pcie = container_of(napi->dev, struct iwl_trans_pcie, napi_dev);
+       trans_pcie = iwl_netdev_to_trans_pcie(napi->dev);
        trans = trans_pcie->trans;
 
        ret = iwl_pcie_rx_handle(trans, rxq->id, budget);
@@ -1131,7 +1136,7 @@ static int _iwl_pcie_rx_init(struct iwl_trans *trans)
                        if (trans_pcie->msix_enabled)
                                poll = iwl_pcie_napi_poll_msix;
 
-                       netif_napi_add(&trans_pcie->napi_dev, &rxq->napi,
+                       netif_napi_add(trans_pcie->napi_dev, &rxq->napi,
                                       poll);
                        napi_enable(&rxq->napi);
                }

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 6c76b2dd6878f5a8a69d3fba44650da86442afe9..d5a887b3a4bbca249924e81569493cf66edbca2a 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -1986,13 +1986,6 @@ static void iwl_trans_pcie_configure(struct iwl_trans *trans,
        trans->command_groups = trans_cfg->command_groups;
        trans->command_groups_size = trans_cfg->command_groups_size;
 
-       /* Initialize NAPI here - it should be before registering to mac80211
-        * in the opmode but after the HW struct is allocated.
-        * As this function may be called again in some corner cases don't
-        * do anything if NAPI was already initialized.
-        */
-       if (trans_pcie->napi_dev.reg_state != NETREG_DUMMY)
-               init_dummy_netdev(&trans_pcie->napi_dev);
 
        trans_pcie->fw_reset_handshake = trans_cfg->fw_reset_handshake;
 }
@@ -2074,6 +2067,8 @@ void iwl_trans_pcie_free(struct iwl_trans *trans)
                iwl_pcie_free_ict(trans);
        }
 
+       free_netdev(trans_pcie->napi_dev);
+
        iwl_pcie_free_invalid_tx_cmd(trans);
 
        iwl_pcie_free_fw_monitor(trans);
@@ -3594,7 +3589,7 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
                               const struct pci_device_id *ent,
                               const struct iwl_cfg_trans_params *cfg_trans)
 {
-       struct iwl_trans_pcie *trans_pcie;
+       struct iwl_trans_pcie *trans_pcie, **priv;
        struct iwl_trans *trans;
        int ret, addr_size;
        const struct iwl_trans_ops *ops = &trans_ops_pcie_gen2;
@@ -3623,6 +3618,18 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
 
        trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 
+       /* Initialize NAPI here - it should be before registering to mac80211
+        * in the opmode but after the HW struct is allocated.
+        */
+       trans_pcie->napi_dev = alloc_netdev_dummy(sizeof(struct iwl_trans_pcie *));
+       if (!trans_pcie->napi_dev) {
+               ret = -ENOMEM;
+               goto out_free_trans;
+       }
+       /* The private struct in netdev is a pointer to struct iwl_trans_pcie */
+       priv = netdev_priv(trans_pcie->napi_dev);
+       *priv = trans_pcie;
+
        trans_pcie->trans = trans;
        trans_pcie->opmode_down = true;
        spin_lock_init(&trans_pcie->irq_lock);
@@ -3637,7 +3644,7 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
                                                   WQ_HIGHPRI | WQ_UNBOUND, 0);
        if (!trans_pcie->rba.alloc_wq) {
                ret = -ENOMEM;
-               goto out_free_trans;
+               goto out_free_ndev;
        }
        INIT_WORK(&trans_pcie->rba.rx_alloc, iwl_pcie_rx_allocator_work);
 
@@ -3757,6 +3764,8 @@ out_free_ict:
        iwl_pcie_free_ict(trans);
 out_no_pci:
        destroy_workqueue(trans_pcie->rba.alloc_wq);
+out_free_ndev:
+       free_netdev(trans_pcie->napi_dev);
 out_free_trans:
        iwl_trans_free(trans);
        return ERR_PTR(ret);